| 1. |
- Agostini, Marco, 1987, et al.
(författare)
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Designing Highly Conductive Functional Groups Improving Guest-Host Interactions in Li/S Batteries
- 2020
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- Li-sulfur batteries are of great interest due to their potential to surpass the energy densities of other battery types, but the low electronic conductivity of both sulfur and its discharge products requires the use of a conductive host material. The most common is the use of different porous carbons which normally are hydrophobic and hardly retain the polar discharge products of the Li/S reaction, such as Li2S and lithium polysulfides (LiPs), at the working electrode. Functionalized hosts have been proposed as a strategy to improve LiPs interactions, including the use of heteroatom doping, organic frameworks, metals, metal oxides, sulfide particles, and conductive polymers. Despite demonstrating an improved cycle life, the functionalized structures often have an intrinsic limitation related to a low electronic conductivity resulting in slow kinetics and poor rate capability of Li/S cells. Herein, recent research trends aimed at designing sulfur electrodes with highly conductive functional groups on nanostructured hosts surface are reviewed. The main concepts, key developments, and parameters for building 3D hosts architectures that enable fast charge rates and long cycle life at high sulfur loadings are discussed.
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| 2. |
- Ahsan, Aisha, et al.
(författare)
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Phase Transitions in Confinements: Controlling Solid to Fluid Transitions of Xenon Atoms in an On-Surface Network
- 2019
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Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829. ; 15:3
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Tidskriftsartikel (refereegranskat)abstract
- This study reports on "phase" transitions of Xe condensates in on-surface confinements induced by temperature changes and local probe excitation. The pores of a metal-organic network occupied with 1 up to 9 Xe atoms are investigated in their propensity to undergo "condensed solid" to "confined fluid" transitions. Different transition temperatures are identified, which depend on the number of Xe atoms in the condensate and relate to the stability of the Xe clustering in the condensed "phase." This work reveals the feature-rich behavior of transitions of confined planar condensates, which provide a showcase toward future "phase-transition" storage media patterned by self-assembly. This work is also of fundamental interest as it paves the way to real space investigations of reversible solid to fluid transitions of magic cluster condensates in an array of extremely well-defined quantum confinements.
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| 3. |
- Aili, Daniel, 1977-, et al.
(författare)
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Colorimetric Protein Sensing by Controlled Assembly of Gold Nanoparticles Functionalized with Synthetic Receptors
- 2009
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 5:21, s. 2445-2452
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Tidskriftsartikel (refereegranskat)abstract
- A novel strategy is described for the colorimetric sensing of proteins, based on polypeptide-functionalized gold nanoparticles. Recognition is accomplished using a polypeptide sensor scaffold designed to specifically bind to the model analyte, human carbonic anhydrase II (HCAII). The extent of particle aggregation, induced by the Zn2+-triggered dimerization and folding of a second polypeptide also present on the surface of the gold nanoparticle, gives a readily detectable colorimetric shift that is dependent on the concentration of the target protein. In the absence of HCAII, particle aggregation results in a major redshift of the plasmon peak, whereas analyte binding prevented the formation of dense aggregates, significantly reducing the magnitude of the redshift. The versatility of the technique is demonstrated using a second model system based on the recognition of a peptide sequence from the tobacco mosaic virus coat protein (TMVP) by a recombinant antibody fragment (Fab57P). Concentrations down to approximate to 10 nM and approximate to 25 nM are detected for HCAII and Fab57P, respectively. This strategy is proposed as a generic platform for robust and specific protein analysis that can be further developed to monitor a wide range of target proteins.
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| 4. |
- Aili, Daniel, et al.
(författare)
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Colorimetric sensing: Small 21/2009
- 2009
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Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 5:21
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The cover picture illustrates a novel concept for colorimetric protein sensing based on the controllable assembly of polypeptide-functionalized gold nanoparticles. Recognition of the analyte is accomplished by polypeptide-based synthetic receptors immobilized on gold nanoparticles. Also present on the particle surface is a de novo-designed helix-loop-helix polypeptide that homodimerizes and folds into four-helix bundles in the presence of Zn2+, resulting in particle aggregation. Analyte binding interferes with the folding-induced aggregation, giving rise to a clearly detectable colorimetric response.
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| 5. |
- Andersson, Per Ola, et al.
(författare)
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Polymorph and size dependent uptake and toxicity of TiO2 nanoparticles in living lung epithelial cells
- 2011
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 7:4, s. 514-523
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Tidskriftsartikel (refereegranskat)abstract
- The cellular uptake and distribution of five types of well-characterized anatase and rutile TiO(2) nanoparticles (NPs) in A549 lung epithelial cells is reported. Static light scattering (SLS), in-vitro Raman microspectroscopy (mu-Raman) and transmission electron spectroscopy (TEM) reveal an intimate correlation between the intrinsic physicochemical properties of the NPs, particle agglomeration, and cellular NP uptake. It is shown that mu-Raman facilitates chemical-, polymorph-, and size-specific discrimination of endosomal-particle cell uptake and the retention of particles in the vicinity of organelles, including the cell nucleus, which quantitatively correlates with TEM and SLS data. Depth-profiling mu-Raman coupled with hyperspectral data analysis confirms the location of the NPs in the cells and shows that the NPs induce modifications of the biological matrix. NP uptake is found to be kinetically activated and strongly dependent on the hard agglomeration size-not the primary particle size-which quantitatively agrees with the measured intracellular oxidative stress. Pro-inflammatory responses are also found to be sensitive to primary particle size.
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| 6. |
- Andõn, F. T., et al.
(författare)
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Biodegradation of Single-Walled Carbon Nanotubes by Eosinophil Peroxidase
- 2013
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Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 9:16, s. 2721-2729
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Tidskriftsartikel (refereegranskat)abstract
- Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H2O 2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H2O2 alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials. Human eosinophil peroxidase (EPO) is able to degrade SWCNTs in vitro in the presence of H2O2. EPO is one of the major oxidant-generating enzymes present in human lungs during inflammatory states. The biodegradation of SWCNTs is evidenced also in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. These results are relevant to potential respiratory exposure to carbon nanotubes.
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| 7. |
- Ao, Xianyu, et al.
(författare)
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Broadband Metallic Absorber on a Non-Planar Substrate
- 2015
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 11:13, s. 1526-1530
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Tidskriftsartikel (refereegranskat)abstract
- Absorbers for visible and near-infrared light are realized by depositing a thin iron layer on arrays of cones which are replicated from a porous template. The replicated conic structure itself is of several micrometers and ineffective at antireflection, but the subsequent deposition of iron on top generates nanometer-size columnar structures, and thus broadband absorption enhancement is achieved.
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| 8. |
- Baldwin, William J., et al.
(författare)
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Dynamic Local Structure in Caesium Lead Iodide: Spatial Correlation and Transient Domains
- 2023
-
Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829.
-
Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites are multifunctional semiconductors with tunable structures and properties. They are highly dynamic crystals with complex octahedral tilting patterns and strongly anharmonic atomic behavior. In the higher temperature, higher symmetry phases of these materials, several complex structural features are observed. The local structure can differ greatly from the average structure and there is evidence that dynamic 2D structures of correlated octahedral motion form. An understanding of the underlying complex atomistic dynamics is, however, still lacking. In this work, the local structure of the inorganic perovskite CsPbI3 is investigated using a new machine learning force field based on the atomic cluster expansion framework. Through analysis of the temporal and spatial correlation observed during large-scale simulations, it is revealed that the low frequency motion of octahedral tilts implies a double-well effective potential landscape, even well into the cubic phase. Moreover, dynamic local regions of lower symmetry are present within both higher symmetry phases. These regions are planar and the length and timescales of the motion are reported. Finally, the spatial arrangement of these features and their interactions are investigated and visualized, providing a comprehensive picture of local structure in the higher symmetry phases.
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| 9. |
- Bally, Marta, 1981, et al.
(författare)
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Liposome and lipid bilayer arrays towards biosensing applications
- 2010
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 6:22, s. 2481-2497
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Tidskriftsartikel (refereegranskat)abstract
- Sensitive and selective biosensors for high-throughput screening are having an increasing impact in modern medical care. The establishment of robust protein biosensing platforms however remains challenging, especially when membrane proteins are involved. Although this type of proteins is of enormous relevance since they are considered in >60% of the pharmaceutical drug targets, their fragile nature (i.e., the requirement to preserve their natural lipid environment to avoid denaturation and loss of function) puts strong additional prerequisites onto a successful biochip. In this review, the leading approaches to create lipid membrane-based arrays towards the creation of membrane protein biosensing platforms are described. Liposomes assembled in micro- and nanoarrays and the successful set-ups containing functional membrane proteins, as well as the use of liposomes in networks, are discussed in the first part. Then, the complementary approaches to create cell-mimicking supported membrane patches on a substrate in an array format will be addressed. Finally, the progress in assembling free-standing (functional) lipid bilayers over nanopore arrays for ion channel sensing will be reported. This review illustrates the rapid pace by which advances are being made towards the creation of a heterogeneous biochip for the high-throughput screening of membrane proteins for diagnostics, drug screening, or drug discovery purposes.
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| 10. |
- Bansal, Akshaya, et al.
(författare)
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Quasi-Continuous Wave Near-Infrared Excitation of Upconversion Nanoparticles for Optogenetic Manipulation of C. elegans
- 2016
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 12:13, s. 1732-1743
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Tidskriftsartikel (refereegranskat)abstract
- Optogenetics is an emerging powerful tool to investigate workings of the nervous system. However, the use of low tissue penetrating visible light limits its therapeutic potential. Employing deep penetrating near-infrared (NIR) light for optogenetics would be beneficial but it cannot be used directly. This issue can be tackled with upconversion nanoparticles (UCNs) acting as nanotransducers emitting at shorter wavelengths extending to the UV range upon NIR light excitation. Although attractive, implementation of such NIR-optogenetics is hindered by the low UCN emission intensity that necessitates high NIR excitation intensities, resulting in overheating issues. A novel quasi-continuous wave (quasi-CW) excitation approach is developed that significantly enhances multiphoton emissions from UCNs, and for the first time NIR light-triggered optogenetic manipulations are implemented in vitro and in C. elegans. The approach developed here enables the activation of channelrhodopsin-2 with a significantly lower excitation power and UCN concentration along with negligible phototoxicity as seen with CW excitation, paving the way for therapeutic optogenetics.
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| 11. |
- Behi, Mohammadreza, et al.
(författare)
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Nanoassembled Peptide Biosensors for Rapid Detection of Matrilysin Cancer Biomarker
- 2020
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 16:16
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Tidskriftsartikel (refereegranskat)abstract
- Early detection of cancer is likely to be one of the most effective means of reducing the cancer mortality rate. Hence, simple and ultra-quick methods for noninvasive detection of early-stage tumors are highly sought-after. In this study, a nanobiosensing platform with a rapid response time of nearly 30 s is introduced for the detection of matrilysin—the salivary gland cancer biomarker—with a limit of detection as low as 30 nm. This sensing platform is based on matrilysin-digestible peptides that bridge gold nanoparticle (AuNPs) cores (≈30–50 nm) and carbon quantum dot (CDs) satellites (≈9 nm). A stepwise synthesis procedure is used for self-assembly of AuNP-peptide-CDs, ensuring their long-term stability. The AuNP-peptide-CDs produce ideal optical signals, with noticeable fluorescence quenching effects. Upon peptide cleavage by matrilysin, CDs leave the surface of AuNPs, resulting in ultra-fast detectable violet and visible fluorescent signals.
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| 12. |
- Ben Romdhane, Ferdaous, et al.
(författare)
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Quasi-2D Cu2S Crystals on Graphene : In-situ Growth and ab-initio Calculations
- 2015
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 11:11, s. 1253-1257
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional crystals of beta-copper sulfide are synthesized in an in-situ electron microscopy experiment. Copper crystals are deposited on an amorphous carbon film containing sulfur. The carbon film graphitizes upon heating and electron irradiation and allows the reaction of Cu and S towards two-dimensional Cu2S crystals. These are energetically favourable and bonded via van der Waals interactions to the graphitic substrate.
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| 13. |
- Benetti, Daniele, et al.
(författare)
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Direct Measurement of Electronic Band Structure in Single Quantum Dots of Metal Chalcogenide Composites
- 2018
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Ingår i: Small (Weinheim an der Bergstrasse, Germany). - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 14:51
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Tidskriftsartikel (refereegranskat)abstract
- Metal chalcogenide quantum dots (QDs) are among the most promising materials as light harvesters in all-inorganic systems for applications in solar cells and production of solar fuels. The electronic band structure of composite QDs formed by lead and cadmium chalcogenides directly grafted on highly oriented pyrolytic graphite surfaces through successive ionic layer absorption and reaction is investigated. Atomic force microscopy and Kelvin probe force microscopy (KPFM) are applied to investigate PbS, CdS, and PbS/CdS QD systems. The variation of the surface potential of individual QDs is measured, investigating the evolution of the electronic band structure as a function of QD size and composition. A shift of the Fermi level toward more negative values occurs when QD size is increased. The shift is more pronounced in CdS than in PbS, while the composite PbS/CdS exhibits an intermediate behavior. The calculated shift is in good agreement with the experiments. These results highlight the ability of KPFM to directly measure the electronic band structure in individual QDs of metal chalcogenide composites. This feature regulates charge dynamics in composite systems, thereby affecting device performance. This work provides valuable insights for applications in several fields, in which charge injection plays a major role.
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| 14. |
- Bernacka Wojcik, Iwona, et al.
(författare)
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Implantable Organic Electronic Ion Pump Enables ABA Hormone Delivery for Control of Stomata in an Intact Tobacco Plant
- 2019
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Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 15:43
-
Tidskriftsartikel (refereegranskat)abstract
- Electronic control of biological processes with bioelectronic devices holds promise for sophisticated regulation of physiology, for gaining fundamental understanding of biological systems, providing new therapeutic solutions, and digitally mediating adaptations of organisms to external factors. The organic electronic ion pump (OEIP) provides a unique means for electronically-controlled, flow-free delivery of ions, and biomolecules at cellular scale. Here, a miniaturized OEIP device based on glass capillary fibers (c-OEIP) is implanted in a biological organism. The capillary form factor at the sub-100 mu m scale of the device enables it to be implanted in soft tissue, while its hyperbranched polyelectrolyte channel and addressing protocol allows efficient delivery of a large aromatic molecule. In the first example of an implantable bioelectronic device in plants, the c-OEIP readily penetrates the leaf of an intact tobacco plant with no significant wound response (evaluated up to 24 h) and effectively delivers the hormone abscisic acid (ABA) into the leaf apoplast. OEIP-mediated delivery of ABA, the phytohormone that regulates plants tolerance to stress, induces closure of stomata, the microscopic pores in leafs epidermis that play a vital role in photosynthesis and transpiration. Efficient and localized ABA delivery reveals previously unreported kinetics of ABA-induced signal propagation.
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| 15. |
- Björk, Per, et al.
(författare)
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Oligothiophene Assemblies Defined by DNA Interaction : From Single Chains to Disordered Clusters
- 2009
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Ingår i: SMALL. - : Wiley. - 1613-6810 .- 1613-6829. ; 5:1, s. 96-103
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Tidskriftsartikel (refereegranskat)abstract
- The organization of conjugated polyelectrolytes (CPEs) interacting with biomolecules sets conditions for the biodetection of biological processes and identity, through the use of optical emission from the CPE. Herein, a well-defined CPE and its binding to DNA is studied. By using dynamic light scattering and circular dichroism spectroscopy, it is shown that the CPE forms a multimolecule ensemble in aqueous solution that is more than doubled it? size when interacting with a small DNA chain, while single chains are evident in ethanol. The related changes in the fluorescence spectra upon polymer aggregation are assigned to oscillator strength redistribution between vibronic transitions in weakly coupled H-aggregates. An enhanced single-molecule spectroscopy technique that allows full control of excitation and emission light polarization is applied to combed and decorated;,DNA chains. It is found that the organization of combed CPE-lambda DNA complexes (when dry on the surface) allows considerable variation of CPE distances and direction relative to the DNA chain. By analysis of the polarization data. energy transfer between the polymer chains in individual complexes is confirmed and their sizes estimated.
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| 16. |
- Björk, Per, et al.
(författare)
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Soft lithographic printing of patterns of stretched DNA and DNA/electronic polymer wires by surface-energy modification and transfer
- 2006
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 2:8-9, s. 1068-1074
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Tidskriftsartikel (refereegranskat)abstract
- Aligned and stretched λ DNA is directed to specific locations on solid substrates. Surface-energy modification of glass substrates by using patterned polydimethylsiloxane (PDMS) stamps is used to direct DNA onto the surface-energy-modified micrometer-scale pattern through molecular combing. As an alternative, patterned and nonpatterned PDMS stamps modified with polymethylmethacrylate (PMMA) are utilized to direct the stretched DNA to the desired location and the results are compared. The DNA is elongated through molecular combing on the stamp and transfer printed onto the surfaces. PMMA-modified stamps show a more defined length of the stretched DNA, as compared to bare PDMS stamps. A combination of these two methods is also demonstrated. As an application example, transfer printing of DNA decorated with a semiconducting conjugated polyelectrolyte is shown. The resulting patterned localization of stretched DNA can be utilized for functional nanodevice structures, as well as for biological applications.
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| 17. |
- Boraschi, Diana, et al.
(författare)
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Addressing Nanomaterial Immunosafety by Evaluating Innate Immunity across Living Species
- 2020
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Ingår i: Small. - Weinheim : Wiley - VCH Verlag GmbH. - 1613-6810 .- 1613-6829. ; 16:21
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Forskningsöversikt (refereegranskat)abstract
- The interaction of a living organism with external foreign agents is a central issue for its survival and adaptation to the environment. Nanosafety should be considered within this perspective, and it should be examined that how different organisms interact with engineered nanomaterials (NM) by either mounting a defensive response or by physiologically adapting to them. Herein, the interaction of NM with one of the major biological systems deputed to recognition of and response to foreign challenges, i.e., the immune system, is specifically addressed. The main focus is innate immunity, the only type of immunity in plants, invertebrates, and lower vertebrates, and that coexists with adaptive immunity in higher vertebrates. Because of their presence in the majority of eukaryotic living organisms, innate immune responses can be viewed in a comparative context. In the majority of cases, the interaction of NM with living organisms results in innate immune reactions that eliminate the possible danger with mechanisms that do not lead to damage. While in some cases such interaction may lead to pathological consequences, in some other cases beneficial effects can be identified.
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| 18. |
- Bordag, Michael, et al.
(författare)
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Shear stress measurements on InAs nanowires by AFM manipulation
- 2007
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Ingår i: Small. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 3:8, s. 1398-1401
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Tidskriftsartikel (refereegranskat)abstract
- On an upward curve? The curvature of an elastically deformed nanowire pinned to a flat surface contains information about the maximum static friction force, and hence the shear stress, between the nanowire and the surface. Here, InAs nanowires are bent in a controlled manner using the tip of an atomic force microscope (see image). The shear stress can be obtained from a simple analysis according to the standard theory of elasticity.
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| 19. |
- Boschi, Alex, et al.
(författare)
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Mesoscopic 3D Charge Transport in Solution-Processed Graphene-Based Thin Films: A Multiscale Analysis
- 2023
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Ingår i: Small. - 1613-6810 .- 1613-6829. ; 19:42
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Tidskriftsartikel (refereegranskat)abstract
- Graphene and related 2D material (GRM) thin films consist of 3D assembly of billions of 2D nanosheets randomly distributed and interacting via van der Waals forces. Their complexity and the multiscale nature yield a wide variety of electrical characteristics ranging from doped semiconductor to glassy metals depending on the crystalline quality of the nanosheets, their specific structural organization ant the operating temperature. Here, the charge transport (CT) mechanisms are studied that are occurring in GRM thin films near the metal-insulator transition (MIT) highlighting the role of defect density and local arrangement of the nanosheets. Two prototypical nanosheet types are compared, i.e., 2D reduced graphene oxide and few-layer-thick electrochemically exfoliated graphene flakes, forming thin films with comparable composition, morphology and room temperature conductivity, but different defect density and crystallinity. By investigating their structure, morphology, and the dependence of their electrical conductivity on temperature, noise and magnetic-field, a general model is developed describing the multiscale nature of CT in GRM thin films in terms of hopping among mesoscopic bricks, i.e., grains. The results suggest a general approach to describe disordered van der Waals thin films.
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| 20. |
- Carlberg, Björn, 1983, et al.
(författare)
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Surface-Confined Synthesis of Silver Nanoparticle Composite Coating on Electrospun Polyimide Nanofibers
- 2011
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 7:21, s. 3057-3066
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Tidskriftsartikel (refereegranskat)abstract
- A methodology for fabricating hierarchical nanostructures by surface-confined synthesis of silver nanoparticles on electrospun polyimide nanofibers is reported. Through surface-confined imide cleavage at the dianhydride domain via immersion in an aqueous KOH solution, potassium polyamate coatings of accurately defined thickness are formed (at a rate of 25 nm h(-1)). By utilizing the ion-exchange capability of the polyamate resin, silver ions are introduced through immersion in an aqueous AgNO(3) solution. Subsequent reduction of the metal ion species leads to the formation of nanoparticles at the fiber surface. Two modes of reduction, chemical and thermal, are investigated in the report, each leading to distinct morphologies of the nanoparticle coatings. Via thermal reduction, a composite surface layer consisting of monodisperse silver nanoparticles (average diameter 5.2 nm) embedded in a re-imidized polyimide matrix is achieved. In the case of chemical reduction, the reduction process occurs preferentially at the surface of the fiber, leading to the formation of silver nanoparticles anchored at the surface, though not embedded, in a polyamic acid matrix. By regulating the modification depth, control of the particle density on the fiber surface is established. In both reduction approaches, the polyimide nanofiber core exhibits maintained integrity.
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| 21. |
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| 22. |
- Caselli, Lucrezia, et al.
(författare)
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Boosting Membrane Interactions and Antimicrobial Effects of Photocatalytic Titanium Dioxide Nanoparticles by Peptide Coating
- 2024
-
Ingår i: Small. - : John Wiley and Sons Inc. - 1613-6810 .- 1613-6829.
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Tidskriftsartikel (refereegranskat)abstract
- Photocatalytic nanoparticles offer antimicrobial effects under illumination due to the formation of reactive oxygen species (ROS), capable of degrading bacterial membranes. ROS may, however, also degrade human cell membranes and trigger toxicity. Since antimicrobial peptides (AMPs) may display excellent selectivity between human cells and bacteria, these may offer opportunities to effectively “target” nanoparticles to bacterial membranes for increased selectivity. Investigating this, photocatalytic TiO2 nanoparticles (NPs) are coated with the AMP LL-37, and ROS generation is found by C11-BODIPY to be essentially unaffected after AMP coating. Furthermore, peptide-coated TiO2 NPs retain their positive ζ-potential also after 1–2 h of UV illumination, showing peptide degradation to be sufficiently limited to allow peptide-mediated targeting. In line with this, quartz crystal microbalance measurements show peptide coating to promote membrane binding of TiO2 NPs, particularly so for bacteria-like anionic and cholesterol-void membranes. As a result, membrane degradation during illumination is strongly promoted for such membranes, but not so for mammalian-like membranes. The mechanisms of these effects are elucidated by neutron reflectometry. Analogously, LL-37 coating promoted membrane rupture by TiO2 NPs for Gram-negative and Gram-positive bacteria, but not for human monocytes. These findings demonstrate that AMP coating may selectively boost the antimicrobial effects of photocatalytic NPs. © 2024 The Authors.
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| 23. |
- Cautela, J., et al.
(författare)
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Sphere–Tubule Superstructures through Supramolecular and Supracolloidal Assembly Pathways
- 2018
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 14:50
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Tidskriftsartikel (refereegranskat)abstract
- While colloids have been widely employed as models for atoms and molecules, the current study proposes to extend their use as building blocks for supracolloidal frameworks. Hereby, the self-assembly between highly anisotropic supramolecular microtubules and soft spherical fluorescent microgels is explored using confocal laser scanning microscopy. The influence of the particle size and charge with respect to the catanionic tubule composition, which consists of two oppositely charged bile salt derivatives, is investigated. Under certain conditions, microgel particles are found to specifically interact with the extremities of the tubular aggregates and hierarchically self-assemble into various superstructures varying from virus-like assemblies to supracolloidal networks. The reported approach is envisioned to open new self-assembly routes toward ordered hybrid superstructures where the spherical colloids act as responsive linkers of tubular structures.
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| 24. |
- Cavallaro, Sara, et al.
(författare)
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Multiparametric Profiling of Single Nanoscale Extracellular Vesicles by Combined Atomic Force and Fluorescence Microscopy : Correlation and Heterogeneity in Their Molecular and Biophysical Features
- 2021
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 17:14
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Tidskriftsartikel (refereegranskat)abstract
- Being a key player in intercellular communications, nanoscale extracellular vesicles (EVs) offer unique opportunities for both diagnostics and therapeutics. However, their cellular origin and functional identity remain elusive due to the high heterogeneity in their molecular and physical features. Here, for the first time, multiple EV parameters involving membrane protein composition, size and mechanical properties on single small EVs (sEVs) are simultaneously studied by combined fluorescence and atomic force microscopy. Furthermore, their correlation and heterogeneity in different cellular sources are investigated. The study, performed on sEVs derived from human embryonic kidney 293, cord blood mesenchymal stromal and human acute monocytic leukemia cell lines, identifies both common and cell line-specific sEV subpopulations bearing distinct distributions of the common tetraspanins (CD9, CD63, and CD81) and biophysical properties. Although the tetraspanin abundances of individual sEVs are independent of their sizes, the expression levels of CD9 and CD63 are strongly correlated. A sEV population co-expressing all the three tetraspanins in relatively high abundance, however, having average diameters of <100 nm and relatively low Young moduli, is also found in all cell lines. Such a multiparametric approach is expected to provide new insights regarding EV biology and functions, potentially deciphering unsolved questions in this field.
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| 25. |
- Chen, Hualong, et al.
(författare)
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Direct Observation of Photon Induced Giant Band Renormalization in 2D PdSe2 Dichalcogenide by Transient Absorption Spectroscopy
- 2023
-
Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 19:46
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Tidskriftsartikel (refereegranskat)abstract
- Insight into fundamental light-matter interaction as well as underlying photo-physical processes is crucial for the development of novel optoelectronic devices. Palladium diselenide (PdSe2), an important representative of emerging 2D noble metal dichalcogenides, has gain considerable attention owing to its unique optical, physical, and chemical properties. In this study, 2D PdSe2 nanosheets (NSs) are prepared using the liquid-phase exfoliation method. A broadband carrier relaxation dynamics from visible to near-infrared bands are revealed using a time-resolved transient absorption spectrometer, giving results that indicate band filling and bandgap renormalization (BGR) effects in the 2D PdSe2 NSs. The observed blue-shift of the transient absorption spectra at the primary stage and the subsequent red-shift can be ascribed to this BGR effect. These findings reveal the many-body character of the 2D TMDs material and may hold keys for applications in the field of optoelectronics and ultrafast photonics.
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| 26. |
- Chen, Jun, et al.
(författare)
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Novel Intrinsic Self-Healing Poly-Silicone-Urea with Super-Low Ice Adhesion Strength
- 2022
-
Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 18:22
-
Tidskriftsartikel (refereegranskat)abstract
- Accumulation of snow and ice often causes problems and even dangerous situations for both industry and the general population. Passive de-icing technologies, e.g., hydrophobic, liquid-infused bionic surfaces, have attracted more and more attention compared with active de-icing technologies, e.g., electric heating, hot air heating, due to the passive de-icing technology's lower energy consumption and sustainability footprint. Using passive de-icing coatings seems to be one of the most promising solutions. However, the previously reported de-icing coatings suffer from high ice adhesion strength or short service life caused by wear. An intrinsic self-healing material based on poly-silicone-urea is developed in this work to address these problems. The material is prepared by introducing dynamic disulfide bonds into the hard phase of the polymer. Experimental results indicate that this poly-silicone-urea has a self-healing efficiency of close to 99%. More interestingly, it is found that the coating prepared from this poly-silicone-urea has a super low ice adhesion force, only 7 ± 1 kPa, which is almost the lowest value compared with previous intrinsic self-healing de-/anti-icing reports. This material can maintain low ice adhesion strength after healing. This intrinsic self-healing poly-silicone-urea can meet several practical applications, opening the door for future sustainable anti-/de-icing technologies.
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| 27. |
- Chen, Jianing, et al.
(författare)
-
Plasmonic Nickel Nanoantennas
- 2011
-
Ingår i: SMALL. - : Wiley. - 1613-6810 .- 1613-6829. ; 7:16, s. 2341-2347
-
Tidskriftsartikel (refereegranskat)abstract
- The fundamental optical properties of pure nickel nanostructures are studied by far-field extinction spectroscopy and optical near-field microscopy, providing direct experimental evidence of the existence of particle plasmon resonances predicted by theory. Experimental and calculated near-field maps allow for unambiguous identification of dipolar plasmon modes. By comparing calculated near-field and far-field spectra, dramatic shifts are found between the near-field and far-field plasmon resonances, which are much stronger than in gold nanoantennas. Based on a simple damped harmonic oscillator model to describe plasmonic resonances, it is possible to explain these shifts as due to plasmon damping.
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| 28. |
- Chen, Mengyun, et al.
(författare)
-
Kinetically Controlled Synthesis of Quasi-Square CsPbI3 Nanoplatelets with Excellent Stability
- 2023
-
Ingår i: Small. - : WILEY-V C H VERLAG GMBH. - 1613-6810 .- 1613-6829.
-
Tidskriftsartikel (refereegranskat)abstract
- Nanoplatelets (NPLs) share excellent luminescent properties with their symmetric quantum dots counterparts and entail special characters benefiting from the shape, like the thickness-dependent bandgap and anisotropic luminescence. However, perovskite NPLs, especially those based on iodide, suffer from poor spectral and phase stability. Here, stable CsPbI3 NPLs obtained by accelerating the crystallization process in ambient-condition synthesis are reported. By this kinetic control, the rectangular NPLs into quasi-square NPLs are tuned, where enlarged width endows the NPLs with a lower surface-area-to-volume ratio (S/V ratio), leading to lower surficial energy and thus improved endurance against NPL fusion (cause for spectral shift or phase transformation). The accelerated crystallization, denoting the fast nucleation and short period of growth in this report, is enabled by preparing a precursor with complete transformation of PbI2 into intermediates (PbI3-), through an additional iodide supplier (e.g., zinc iodide). The excellent color stability of the materials remains in the light-emitting diodes under various bias stresses.
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| 29. |
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| 30. |
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| 31. |
- Cisneros, David A., et al.
(författare)
-
Creating ultrathin nanoscopic collagen matrices for biological and biotechnological applications
- 2007
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 3:6, s. 956-963
-
Tidskriftsartikel (refereegranskat)abstract
- The biofunctionalization of materials creates interfaces on which proteins, cells, or tissues can fulfill native or desired tasks. Here we report how to control the assembly of type I collagen into well-defined nanoscopic matrices of different patterns. Collagen fibrils in these ultrathin (approximately 3 nm) matrices maintained their native structure as observed in vivo. This opens up the possibility to create programmable biofunctionalized matrices using collagen-binding proteins or proteins fused with collagen-binding domains. Applied to eukaryotic cells, these nanostructured matrices can direct cellular processes such as adhesion, orientation and migration.
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| 32. |
- Conache, Gabriela, et al.
(författare)
-
Friction measurements of InAs nanowires on Silicon nitride by AFM manipulation
- 2009
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Ingår i: Small. - Weinheim, Germany : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 5:2, s. 203-207
-
Tidskriftsartikel (refereegranskat)abstract
- A study was conducted to perform friction measurements of InAs nanowires (NW) on silicon nitride (Si 3N 4) through atomic force microscopy (AFM) manipulation. The investigations revealed the friction force per unit length for sliding and static friction over a range of nanowire diameters. It was found that there is a significant difference between the coefficients of the two sliding modes for large wires. It was also found that the difference between the two sliding modes disappears at smaller diameters and the sliding friction becomes equal with the static friction. The AFM investigations were performed on a Nanoscope IIIa Dimension 3100, using rectangular cantilevers, with a nominal spring constant of 30 N m -1. The nanowires were manipulated, using the 'Retrace Lift' mode of the AFM controller. The friction force per unit length was gathered from the local curvature of the NWs, using standard elasticity theory.
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| 33. |
- Concina, Isabella, et al.
(författare)
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Metal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells
- 2015
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 11:15, s. 1744-1774
-
Tidskriftsartikel (refereegranskat)abstract
- This Review provides a brief summary of the most recent research developments in the synthesis and application of nanostructured metal oxide semiconductors for dye sensitized and quantum dot sensitized solar cells. In these devices, the wide bandgap semiconducting oxide acts as the photoanode, which provides the scaffold for light harvesters (either dye molecules or quantum dots) and electron collection. For this reason, proper tailoring of the optical and electronic properties of the photoanode can significantly boost the functionalities of the operating device. Optimization of the functional properties relies with modulation of the shape and structure of the photoanode, as well as on application of different materials (TiO2, ZnO, SnO2) and/or composite systems, which allow fine tuning of electronic band structure. This aspect is critical because it determines exciton and charge dynamics in the photoelectrochemical system and is strictly connected to the photoconversion efficiency of the solar cell. The different strategies for increasing light harvesting and charge collection, inhibiting charge losses due to recombination phenomena, are reviewed thoroughly, highlighting the benefits of proper photoanode preparation, and its crucial role in the development of high efficiency dye sensitized and quantum dot sensitized solar cells.
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| 34. |
- Concina, Isabella, et al.
(författare)
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Solar Cells : Metal Oxide Semiconductors for Dye- and Quantum-Dot-Sensitized Solar Cells
- 2015
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 11:15, s. 1743-
-
Tidskriftsartikel (refereegranskat)abstract
- Metal oxide semiconductors are an appealing class of material, extensively used as photoanodes in excitonic solar cells such as dye- and quantum dot-sensitized solar cells. On page 1744, I. Concina and A. Vomiero describe how proper tailoring of the shape, composition, and crystalline structure of these materials can significantly boost the performances of these solar energy converting devices by ameliorating the processes of exciton separation, charge transport, and collection, while reducing charge losses due to recombination and back reactions.
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| 35. |
- Cronholm, Pontus, et al.
(författare)
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Intracellular Uptake and Toxicity of Ag and CuO Nanoparticles : A Comparison Between Nanoparticles and their Corresponding Metal Ions
- 2013
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 9:7, s. 970-982
-
Tidskriftsartikel (refereegranskat)abstract
- An increased understanding of nanoparticle toxicity and its impact on human health is essential to enable a safe use of nanoparticles in our society. The aim of this study is to investigate the role of a Trojan horse type mechanism for the toxicity of Ag-nano and CuO-nano particles and their corresponding metal ionic species (using CuCl2 and AgNO3), i.e., the importance of the solid particle to mediate cellular uptake and subsequent release of toxic species inside the cell. The human lung cell lines A549 and BEAS-2B are used and cell death/membrane integrity and DNA damage are investigated by means of trypan blue staining and the comet assay, respectively. Chemical analysis of the cellular dose of copper and silver is performed using atomic absorption spectroscopy. Furthermore, transmission electron microscopy, laser scanning confocal microscopy, and confocal Raman microscopy are employed to study cellular uptake and particle-cell interactions. The results confirm a high uptake of CuO-nano and Ag-nano compared to no, or low, uptake of the soluble salts. CuO-nano induces both cell death and DNA damage whereas CuCl2 induces no toxicity. The opposite is observed for silver, where Ag-nano does not cause any toxicity, whereas AgNO3 induces a high level of cell death. In conclusion: CuO-nano toxicity is predominantly mediated by intracellular uptake and subsequent release of copper ions, whereas no toxicity is observed for Ag-nano due to low release of silver ions within short time periods.
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| 36. |
- De Sloovere, Dries, et al.
(författare)
-
Phase Engineering via Aluminum Doping Enhances the Electrochemical Stability of Lithium-Rich Cobalt-Free Layered Oxides for Lithium-Ion Batteries
- 2024
-
Ingår i: Small. - 1613-6810 .- 1613-6829.
-
Tidskriftsartikel (refereegranskat)abstract
- Lithium-rich, cobalt-free oxides are promising potential positive electrode materials for lithium-ion batteries because of their high energy density, lower cost, and reduced environmental and ethical concerns. However, their commercial breakthrough is hindered because of their subpar electrochemical stability. This work studies the effect of aluminum doping on Li1.26Ni0.15Mn0.61O2 as a lithium-rich, cobalt-free layered oxide. Al doping suppresses voltage fade and improves the capacity retention from 46% for Li1.26Ni0.15Mn0.61O2 to 67% for Li1.26Ni0.15Mn0.56Al0.05O2 after 250 cycles at 0.2 C. The undoped material has a monoclinic Li2MnO3-type structure with spinel on the particle edges. In contrast, Al-doped materials (Li1.26Ni0.15Mn0.61-xAlxO2) consist of a more stable rhombohedral phase at the particle edges, with a monoclinic phase core. For this core-shell structure, the formation of Mn3+ is suppressed along with the material's decomposition to a disordered spinel, and the amount of the rhombohedral phase content increases during galvanostatic cycling. Whereas previous studies generally provided qualitative insight into the degradation mechanisms during electrochemical cycling, this work provides quantitative information on the stabilizing effect of the rhombohedral shell in the doped sample. As such, this study provides fundamental insight into the mechanisms through which Al doping increases the electrochemical stability of lithium-rich cobalt-free layered oxides.
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| 37. |
- Do, Xuan Huy, et al.
(författare)
-
Membrane Assemblies with Soft Protective Layers : Dense and Gel-Type Polybenzimidazole Membranes and Their Use in Vanadium Redox Flow Batteries
- 2022
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 18:50
-
Tidskriftsartikel (refereegranskat)abstract
- Polybenzimidazole (PBI) membranes show excellent chemical stability and low vanadium crossover in vanadium redox flow batteries (VRFBs), but their high resistance is challenging. This work introduces a concept, membrane assemblies of a highly selective 2 µm thin PBI membrane between two 60 µm thick highly conductive PBI gel membranes, which act as soft protective layers against external mechanical forces and astray carbon fibers from the electrode. The soft layers are produced by casting phosphoric acid solutions of commercial PBI powder into membranes and exchanging the absorbed acid into sulfuric acid. A conductivity of 565 mS cm−1 is achieved. A stability test indicates that gel mPBI and dense PBI-OO have higher stability than dense mPBI and dense py-PBI, and gel/PBI-OO/gel is successfully tested for 1070 cycles (ca. 1000 h) at 100 mA cm−2 in the VRFB. The initial energy efficiency (EE) for the first 50 cycles is 90.5 ± 0.2%, and after a power outage stabilized at 86.3 ± 0.5% for the following 500 cycles. The initial EE is one of the highest published so far, and the materials cost for a membrane assembly is 12.35 U.S. dollars at a production volume of 5000 m2, which makes these membranes very attractive for commercialization.
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| 38. |
- Dobrovolsky, Alexandr, et al.
(författare)
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Energy Upconversion in GaP/GaNP Core/Shell Nanowires for Enhanced Near-Infrared Light Harvesting
- 2014
-
Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 10:21, s. 4403-4408
-
Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires (NWs) have recently gained increasing interest due to their great potential for photovoltaics. A novel material system based on GaNP NWs is considered to be highly suitable for applications in efficient multi-junction and intermediate band solar cells. This work shows that though the bandgap energies of GaNx P1-x alloys lie within the visible spectral range (i.e., within 540-650 nm for the currently achievable x < 3%), coaxial GaNP NWs grown on Si substrates can also harvest infrared light utilizing energy upconversion. This energy upconversion can be monitored via anti-Stokes near-band-edge photoluminescence (PL) from GaNP, visible even from a single NW. The dominant process responsible for this effect is identified as being due to two-step two-photon absorption (TS-TPA) via a deep level lying at about 1.28 eV above the valence band, based on the measured dependences of the anti-Stokes PL on excitation power and wavelength. The formation of the defect participating in the TS-TPA process is concluded to be promoted by nitrogen incorporation. The revealed defect-mediated TS-TPA process can boost efficiency of harvesting solar energy in GaNP NWs, beneficial for applications of this novel material system in third-generation photovoltaic devices.
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| 39. |
- Dobrovolsky, Alexander, et al.
(författare)
-
Fabry-Perot Microcavity Modes in Single GaP/GaNP Core/Shell Nanowires
- 2015
-
Ingår i: Small. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 11:47, s. 6331-6337
-
Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires (NWs) are attracting increasing interest as nanobuilding blocks for optoelectronics and photonics. A novel material system that is highly suitable for these applications are GaNP NWs. In this article, we show that individual GaP/GaNP core/shell nanowires (NWs) grown by molecular beam epitaxy on Si substrates can act as Fabry-Perot (FP) microcavities. This conclusion is based on results of microphotoluminescence (μ-PL) measurements performed on individual NWs, which reveal periodic undulations of the PL intensity that follow an expected pattern of FP cavity modes. The cavity is concluded to be formed along the NW axis with the end facets acting as reflecting mirrors. The formation of the FP modes is shown to be facilitated by an increasing index contrast with the surrounding media. Spectral dependence of the group refractive index is also determined for the studied NWs. The observation of the FP microcavity modes in the GaP/GaNP core/shell NWs can be considered as a first step toward achieving lasing in this quasidirect bandgap semiconductor in the NW geometry.
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| 40. |
- Duznovic, I., et al.
(författare)
-
Ultrasensitive and Selective Protein Recognition with Nanobody-Functionalized Synthetic Nanopores
- 2021
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 17:33
-
Tidskriftsartikel (refereegranskat)abstract
- The development of flexible and reconfigurable sensors that can be readily tailored toward different molecular analytes constitutes a key goal and formidable challenge in biosensing. In this regard, synthetic nanopores have emerged as potent physical transducers to convert molecular interactions into electrical signals. Yet, systematic strategies to functionalize their surfaces with receptor proteins for the selective detection of molecular analytes remain scarce. Addressing these limitations, a general strategy is presented to immobilize nanobodies in a directional fashion onto the surface of track-etched nanopores exploiting copper-free click reactions and site-specific protein conjugation systems. The functional immobilization of three different nanobodies is demonstrated in ligand binding experiments with green fluorescent protein, mCherry, and α-amylase (α-Amy) serving as molecular analytes. Ligand binding is resolved using a combination of optical and electrical recordings displaying quantitative dose–response curves. Furthermore, a change in surface charge density is identified as the predominant molecular factor that underlies quantitative dose–responses for the three different protein analytes in nanoconfined geometries. The devised strategy should pave the way for the systematic functionalization of nanopore surfaces with biological receptors and their ability to detect a variety of analytes for diagnostic purposes. © 2021 The Authors. Small published by Wiley-VCH GmbH
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| 41. |
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| 42. |
- Eklöf, Johnas, 1988, et al.
(författare)
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Parallel Fabrication of Self‐Assembled Nanogaps for Molecular Electronic Devices
- 2018
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 14:50
-
Tidskriftsartikel (refereegranskat)abstract
- Single molecule electronics might be a way to add additional function to nanoscale devices and continue miniaturization beyond current state of the art. Here, a combined top‐down and bottom‐up strategy is employed to assemble single molecules onto prefabricated electrodes. Protodevices, which are self‐assembled nanogaps composed by two gold nanoparticles linked by a single or a few molecules, are guided onto top‐down prefabricated nanosized nickel electrodes with sandwiched palladium layers. It is shown that an optimized geometry of multilayered metallic (top‐down) electrodes facilitates the assembly of (bottom‐up) nanostructures by surface charge interactions. Moreover, such assembly process results in an electrode–nanoparticle interface free from linking molecules that enable electrical measurements to probe electron transport properties of the nanoparticle–molecule–nanoparticle protodevices.
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| 43. |
- Fan, Ke, et al.
(författare)
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Sacrificial W Facilitates Self-Reconstruction with Abundant Active Sites for Water Oxidation
- 2022
-
Ingår i: Marine and Petroleum Geology. - : Wiley. - 0264-8172 .- 1873-4073. ; 138
-
Tidskriftsartikel (refereegranskat)abstract
- Water oxidation is an important reaction for multiple renewable energy conversion and storage-related devices and technologies. High-performance and stable electrocatalysts for the oxygen evolution reaction (OER) are urgently required. Bimetallic (oxy)hydroxides have been widely used in alkaline OER as electrocatalysts, but their activity is still not satisfactory due to insufficient active sites. In this research, A unique and efficient approach of sacrificial W to prepare CoFe (oxy)hydroxides with abundant active species for OER is presented. Multiple ex situ and operando/in situ characterizations have validated the self-reconstruction of the as-prepared CoFeW sulfides to CoFe (oxy) hydroxides in alkaline OER with synchronous W etching. Experiments and theoretical calculations show that the sacrificial W in this process induces metal cation vacancies, which facilitates the in situ transformation of the intermediate metal hydroxide to CoFe-OOH with more high-valence Co(III), thus creating abundant active species for OER. The Co(III)-rich environment endows the in situ formed CoFe oxyhydroxide with high catalytic activity for OER on a simple flat glassy carbon electrode, outperforming those not treated by the sacrificial W procedure. This research demonstrates the influence of etching W on the electrocatalytic performance, and provides a low-cost means to improve the active sites of the in situ self-reconstructed bimetallic oxyhydroxides for OER.
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| 44. |
- Frykholm, Karolin, 1977, et al.
(författare)
-
Probing Physical Properties of a DNA- Protein Complex Using Nanofluidic Channels
- 2014
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 10:5, s. 884-887
-
Tidskriftsartikel (refereegranskat)abstract
- A method to investigate physical properties of a DNA-protein complex in solution is demonstrated. By using tapered nanochannels and lipid passivation the persistence length of a RecA filament formed on double-stranded DNA is determined to 1.15 μm, in agreement with the literature, without attaching protein or DNA to any handles or surfaces.
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| 45. |
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| 46. |
- Gan, Z., et al.
(författare)
-
Ultraviolet Photoluminescence of Carbon Nanospheres and its Surface Plasmon-Induced Enhancement
- 2018
-
Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 14:16
-
Tidskriftsartikel (refereegranskat)abstract
- Ultraviolet (UV) light can be used in versatile applications ranging from photoelectronic devices to biomedical imaging. In the development of new UV light sources, in this study, stable UV emission at ≈350 nm is unprecedentedly obtained from carbon nanospheres (CNSs). The origin of the UV fluorescence is comprehensively investigated via various characterization methods, including Raman and Fourier transform infrared analyses, with comparison to the visible emission of carbon nanodots. Based on the density functional calculations, the UV fluorescence is assigned to the carbon nanostructures bonded to bridging O atoms and dangling –OH groups. Moreover, a twofold enhancement in the UV emission is acquired for Au-carbon core-shell nanospheres (Au-CNSs). This remarkable modification of the UV emission is primarily ascribed to charge transfer between the CNSs and the Au surface.
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| 47. |
- Gao, Lingfeng, et al.
(författare)
-
A Facile Approach for Elemental-Doped Carbon Quantum Dots and Their Application for Efficient Photodetectors
- 2021
-
Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 17:52
-
Tidskriftsartikel (refereegranskat)abstract
- The present work demonstrates a facile hydrothermal approach to synthesize lanthanide-doped carbon quantum dots (CQDs) with europium and/or gadolinium elements. Taking the advantage of broadband adsorption in the ultraviolet-visible region, the doped QDs are directly used as building blocks for photo-electrochemical (PEC)-type photodetectors (PDs) and their performance is systematically investigated under various conditions. The europium (Eu) and gadolinium (Gd) co-doped (C:EuGd) QDs exhibit better photo-response than the single-elemental doped ones and also show outstanding long-term stability. According to the apparent response to light from 350 to 400 nm, the C:EuGd QDs are demonstrated to hold great potential for narrow-band PDs. This work highlights the practical applications of lanthanide-doped CQDs for PDs, and the results are beneficial for the development of elemental-doped CQDs in general.
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| 48. |
- Gao, Lingfeng, et al.
(författare)
-
Ultra-Small 2D PbS Nanoplatelets : Liquid-Phase Exfoliation and Emerging Applications for Photo-Electrochemical Photodetectors
- 2021
-
Ingår i: Small. - : John Wiley & Sons. - 1613-6810 .- 1613-6829. ; 17:5
-
Tidskriftsartikel (refereegranskat)abstract
- 2D PbS nanoplatelets (NPLs) form an emerging class of photoactive materials and have been proposed as robust materials for high-performance optoelectronic devices. However, the main drawback of PbS NPLs is the large lateral size, which inhibits their further investigations and practical applications. In this work, ultra-small 2D PbS NPLs with uniform lateral size (11.2 +/- 1.7 nm) and thickness (3.7 +/- 0.9 nm, approximate to 6 layers) have been successfully fabricated by a facile liquid-phase exfoliation approach. Their transient optical response and photo-response behavior are evaluated by femtosecond-resolved transient absorption and photo-electrochemical (PEC) measurements. It is shown that the NPLs-based photodetectors (PDs) exhibit excellent photo-response performance from UV to the visible range, showing extremely high photo-responsivity (27.81 mA W-1) and remarkable detectivity (3.96 x 10(10) Jones), which are figures of merit outperforming currently reported PEC-type PDs. The outstanding properties are further analyzed based on the results of first-principle calculations, including electronic band structure and free energies for the oxygen evolution reaction process. This work highlights promising applications of ultra-small 2D PbS NPLs with the potential for breakthrough developments also in other fields of optoelectronic devices.
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| 49. |
- Garcia Fernandez, Alberto, et al.
(författare)
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Experimental and Theoretical Core Level and Valence Band Analysis of Clean Perovskite Single Crystal Surfaces
- 2022
-
Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 18:13
-
Tidskriftsartikel (refereegranskat)abstract
- A detailed understanding of the surface and interface properties of lead halide perovskites is of interest for several applications, in which these materials may be used. To develop this understanding, the study of clean crystalline surfaces can be an important stepping stone. In this work, the surface properties and electronic structure of two different perovskite single crystal compositions (MAPbI(3) and Cs(x)FA(1-)(x)PbI(3)) are investigated using synchrotron-based soft X-ray photoelectron spectroscopy (PES), molecular dynamics simulations, and density functional theory. The use of synchrotron-based soft X-ray PES enables high surface sensitivity and nondestructive depth-profiling. Core level and valence band spectra of the single crystals are presented. The authors find two carbon 1s contributions at the surface of MAPbI(3) and assign these to MA(+) ions in an MAI-terminated surface and to MA(+) ions below the surface. It is estimated that the surface is predominantly MAI-terminated but up to 30% of the surface can be PbI2-terminated. The results presented here can serve as reference spectra for photoelectron spectroscopy investigations of technologically relevant polycrystalline thin films, and the findings can be utilized to further optimize the design of device interfaces.
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| 50. |
- Gholamrezaie, Fatemeh, et al.
(författare)
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Charge Trapping by Self-Assembled Monolayers as the Origin of the Threshold Voltage Shift in Organic Field-Effect Transistors
- 2012
-
Ingår i: Small. - : Wiley-VCH Verlag. - 1613-6810 .- 1613-6829. ; 8:2, s. 241-245
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Tidskriftsartikel (refereegranskat)abstract
- The threshold voltage is an important property of organic field-effect transistors. By applying a self-assembled monolayer (SAM) on the gate dielectric, the value can be tuned. After electrical characterization, the semiconductor is delaminated. The surface potentials of the revealed SAM perfectly agree with the threshold voltages, which demonstrate that the shift is not due to the dipolar contribution, but due to charge trapping by the SAM.
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