| 1. |
- Geissel, Felix J., et al.
(författare)
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Nanostructured Ag-Bioglass Implant Coatings with Antibacterial and Osteogenic Activity
- 2023
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Ingår i: Advanced Materials Interfaces. - : Wiley-VCH Verlagsgesellschaft. - 2196-7350. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Bone implant failure due to aseptic loosening and biofilm infections is an increasing healthcare problem. Implants may be coated with nanoparticles to avoid bacterial colonization and promote osseointegration. However, these nanocoatings often require long, expensive, and complex manufacturing routes with limited clinical translation potential. Here, a multifunctional nanoparticle coating consisting of silver (Ag) and bioglass (BG) is investigated to overcome current limitations by providing synchronously antibacterial and osteogenic effect. Flame spray pyrolysis (FSP) is exploited as a scalable and reproducible process to synthesize large quantities of nanoparticles and deposit them on titanium (Ti) substrates. The deposited nanocoatings show a homogeneous morphology and biomineralize after soaking in simulated body fluid (SBF), while their adhesion on Ti substrates is promoted by in situ flame annealing. The Ag+ ion release from Ag containing BG samples inhibits Staphylococcus aureus biofilm formation up to 3 log units, while the osteogenic responses of pre-osteoblastic cells directly grown on AgBG samples show similar levels of alkaline phosphatase activity, calcium and collagen production when compared to pure Ti. The inexpensively synthesized multifunctional AgBG nanostructured implant coatings exert a high bioactivity and antibacterial response while maintaining high biocompatibility. The insights of this study can direct the development of multifunctional implant coatings.
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| 2. |
- Sotiriou, Georgios A., et al.
(författare)
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Thermal Energy Dissipation by SiO2-Coated Plasmonic-Superpararnagnetic Nanoparticles in Alternating Magnetic Fields
- 2013
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 25:22, s. 4603-4612
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Tidskriftsartikel (refereegranskat)abstract
- Multifunctional nanoparticles show great potential in the biomedical field and may help the diagnosis and therapy of diseases. Superparamagnetic nanoparticles are especially attractive because of their ability to dissipate thermal energy in an alternating magnetic field. Furthermore, plasmonic nanoparticles can be effectively used in non- or minimally invasive therapy of tumors exploiting their plasmonic photothermal effect. Here, hybrid plasmonicmagnetic Ag/Fe2O3 nanoparticles are made by flame aerosol technology. These nanoparticles can be in situ encapsulated with an amorphous nanothin SiO2 film to facilitate their dispersion and block any toxicity from Ag/Fe2O3. Detailed physicochemical characterization, including electron microscopy, electron dispersive X-ray spectroscopy, and X-ray diffraction, is performed. Furthermore, their magnetic properties are characterized in detail by monitoring their hysteresis, first-order-reversal-curves, and isothermal remanent magnetization. Finally, the effect of SiO2 and Agcontent on the specific absorption rate (SAR) of the hybrid Ag/Fe2O3 nanoparticles is investigated. The obtained understanding will help the rational design and engineering of multifunctional hybrid nanoprobes targeting specific biomedical applications.
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| 3. |
- Bletsa, Eleni, et al.
(författare)
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Highly durable photocatalytic titanium suboxide–polymer nanocomposite films with visible light-triggered antibiofilm activity
- 2023
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 454, part 1
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial biofilms on medical devices may result in infections with significant societal burden. One drug-free strategy against biofilms is photocatalysis, in which a semiconducting coating is applied on the medical device and irradiated with light to generate reactive oxygen species providing an on-demand disinfection approach. However, most photocatalytic materials are active in the harmful UV range rendering them unsuitable for biomedical applications. Furthermore, the main manufacturing bottleneck today for antibiofilm coatings is their poor durability. To address these challenges, here we produced silver/titanium-suboxide nanoparticles that are photocatalytically active in the visible-light range. Moreover, we directly deposited the nanoparticles as porous coatings on substrates in situ during their aerosol synthesis. To enhance their durability, we infused the fabricated porous coatings with a polymer solution barely covering the photocatalytic particle film, resulting in the formation of polymer nanocomposite coatings. The optimized polymer nanocomposite films exhibit several cycles of triggered, on-demand biofilm eradication activity under short visible light illumination of 15–90 min with no significant intrinsic cytotoxicity to mammalian cells. The developed films can be considered as a suitable coating material for medical devices, such as catheters, ventilators, wound meshes, and others, that may require repeated disinfection during use.
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| 4. |
- Hempel, Nele-Johanna, et al.
(författare)
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The Effect of the Molecular Weight of Polyvinylpyrrolidone and the Model Drug on Laser-Induced In Situ Amorphization
- 2021
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 26:13
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Tidskriftsartikel (refereegranskat)abstract
- Laser radiation has been shown to be a promising approach for in situ amorphization, i.e., drug amorphization inside the final dosage form. Upon exposure to laser radiation, elevated temperatures in the compacts are obtained. At temperatures above the glass transition temperature (T-g) of the polymer, the drug dissolves into the mobile polymer. Hence, the dissolution kinetics are dependent on the viscosity of the polymer, indirectly determined by the molecular weight (M-w) of the polymer, the solubility of the drug in the polymer, the particle size of the drug and the molecular size of the drug. Using compacts containing 30 wt% of the drug celecoxib (CCX), 69.25 wt% of three different M-w of polyvinylpyrrolidone (PVP: PVP12, PVP17 or PVP25), 0.25 wt% plasmonic nanoaggregates (PNs) and 0.5 wt% lubricant, the effect of the polymer M-w on the dissolution kinetics upon exposure to laser radiation was investigated. Furthermore, the effect of the model drug on the dissolution kinetics was investigated using compacts containing 30 wt% of three different drugs (CCX, indomethacin (IND) and naproxen (NAP)), 69.25 wt% PVP12, 0.25 wt% PN and 0.5 wt% lubricant. In perfect correlation to the Noyes-Whitney equation, this study showed that the use of PVP with the lowest viscosity, i.e., the lowest M-w (here PVP12), led to the fastest rate of amorphization compared to PVP17 and PVP25. Furthermore, NAP showed the fastest rate of amorphization, followed by IND and CCX in PVP12 due to its high solubility and small molecular size.
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| 5. |
- Hempel, Nele-Johanna, et al.
(författare)
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The Influence of Drug-Polymer Solubility on Laser-Induced In Situ Drug Amorphization Using Photothermal Plasmonic Nanoparticles
- 2021
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Ingår i: Pharmaceutics. - : MDPI. - 1999-4923. ; 13:6
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Tidskriftsartikel (refereegranskat)abstract
- In this study, laser-induced in situ amorphization (i.e., amorphization inside the final dosage form) of the model drug celecoxib (CCX) with six different polymers was investigated. The drug-polymer combinations were studied with regard to the influence of (i) the physicochemical properties of the polymer, e.g., the glass transition temperature (T-g) and (ii) the drug-polymer solubility on the rate and degree of in situ drug amorphization. Compacts were prepared containing 30 wt% CCX, 69.25 wt% polymer, 0.5 wt% lubricant, and 0.25 wt% plasmonic nanoparticles (PNs) and exposed to near-infrared laser radiation. Upon exposure to laser radiation, the PNs generated heat, which allowed drug dissolution into the polymer at temperatures above its T-g, yielding an amorphous solid dispersion. It was found that in situ drug amorphization was possible for drug-polymer combinations, where the temperature reached during exposure to laser radiation was above the onset temperature for a dissolution process of the drug into the polymer, i.e., T-DStart. The findings of this study showed that the concept of laser-induced in situ drug amorphization is applicable to a range of polymers if the drug is soluble in the polymer and temperatures during the process are above T-DStart.
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| 6. |
- Hempel, Nele-Johanna, et al.
(författare)
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Utilizing Laser Activation of Photothermal Plasmonic Nanoparticles to Induce On-Demand Drug Amorphization inside a Tablet
- 2021
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 18:6, s. 2254-2262
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Tidskriftsartikel (refereegranskat)abstract
- Poor aqueous drug solubility represents a major challenge in oral drug delivery. A novel approach to overcome this challenge is drug amorphization inside a tablet, that is, on-demand drug amorphization. The amorphous form is a thermodynamically instable, disordered solid-state with increased dissolution rate and solubility compared to its crystalline counterpart. During on-demand drug amorphization, the drug molecularly disperses into a polymer to form an amorphous solid at elevated temperatures inside a tablet. This study investigates, for the first time, the utilization of photothermal plasmonic nanoparticles for on-demand drug amorphization as a new pharmaceutical application. For this, near-IR photothermal plasmonic nanoparticles were tableted together with a crystalline drug (celecoxib) and a polymer (polyvinylpyrrolidone). The tablets were subjected to a near-IR laser at different intensities and durations to study the rate of drug amorphization under each condition. During laser irradiation, the plasmonic nanoparticles homogeneously heated the tablet. The temperature was directly related to the rate and degree of amorphization. Exposure times as low as 180 s at 1.12 W cm(-2) laser intensity with only 0.25 wt % plasmonic nanoparticles and up to 50 wt % drug load resulted in complete drug amorphization. Therefore, near-IR photothermal plasmonic nanoparticles are promising excipients for on-demand drug amorphization with laser irradiation.
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| 7. |
- Henning, Dorian F., et al.
(författare)
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Luminescent CeO2:Eu3+ nanocrystals for robust in situ H2O2 real-time detection in bacterial cell cultures
- 2019
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Ingår i: Biosensors & bioelectronics. - : ELSEVIER ADVANCED TECHNOLOGY. - 0956-5663 .- 1873-4235. ; 132, s. 286-293
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogen peroxide (H2O2) quantification in biomedicine is valuable as inflammation biomarker but also in assays employing enzymes that generate or consume H2O2 linked to a specific biomarker. Optical H2O2 detection is typically performed through peroxidase-coupled reactions utilizing organic dyes that suffer, however, from poor stability/reproducibility and also cannot be employed in situ in dynamic complex cell cultures to monitor H2O2 levels in real-time. Here, we utilize enzyme-mimetic CeO2 nanocrystals that are sensitive to H2O2 and study the effect of H2O2 presence on their electronic and luminescent properties. We produce and dope with Eu3+ these particles in a single-step by flame synthesis and directly deposit them on Si and glass substrates to fabricate nanoparticle layers to monitor in real-time and in situ the H2O2 concentrations generated by Streptococcus pneumoniae clinical isolates. Furthermore, the small CeO2:Eu3+ nanocrystals are combined in a single-step with larger, non-responsive Y2O3:Tb3+ nanoparticles during their double-nozzle flame synthesis to engineer hybrid luminescent nanoaggregates as ratiometric robust biosensors. We demonstrate the functionality of these biosensors by monitoring their response in the presence of a broad range of H2O2 concentrations in vitro from S. pneumoniae, highlighting their potential for facile real-time H2O2 detection in vitro in cell cultures.
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| 8. |
- Hirt, Ann M., et al.
(författare)
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Effect of size, composition, and morphology on magnetic performance : First-order reversal curves evaluation of iron oxide nanoparticles
- 2014
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 115:4
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Tidskriftsartikel (refereegranskat)abstract
- Superparamagnetic nanoparticles are employed in a broad range of applications that demand detailed magnetic characterization for superior performance, e. g., in drug delivery or cancer treatment. Magnetic hysteresis measurements provide information on saturation magnetization and coercive force for bulk material but can be equivocal for particles having a broad size distribution. Here, first-order reversal curves (FORCs) are used to evaluate the effective magnetic particle size and interaction between equally sized magnetic iron oxide (Fe2O3) nanoparticles with three different morphologies: (i) pure Fe2O3, (ii) Janus-like, and (iii) core/shell Fe2O3/SiO2 synthesized using flame technology. By characterizing the distribution in coercive force and interaction field from the FORC diagrams, we find that the presence of SiO2 in the core/shell structures significantly reduces the average coercive force in comparison to the Janus-like Fe2O3/SiO2 and pure Fe2O3 particles. This is attributed to the reduction in the dipolar interaction between particles, which in turn reduces the effective magnetic particle size. Hence, FORC analysis allows for a finer distinction between equally sized Fe2O3 particles with similar magnetic hysteresis curves that can significantly influence the final nanoparticle performance. (C) 2014 AIP Publishing LLC.
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| 9. |
- Li, Haipeng, et al.
(författare)
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Democratizing robust SERS nano-sensors for food safety diagnostics
- 2023
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Ingår i: Chemical Engineering Journal. - 1385-8947 .- 1873-3212. ; 470
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Tidskriftsartikel (refereegranskat)abstract
- Pesticide residues in food products cause human health concerns through food contamination, thereby necessitating their rapid and facile detection. Although surface-enhanced Raman scattering (SERS) technique can rapidly and reliably detect pesticide residues, its application in food safety diagnostics is restricted by its high expense, low scalability, and low reproducibility of the necessary sensors. Herein, we present a low-cost, large-scale, and highly reproducible nanofabrication route for SERS nano-sensors, based on the thermophoresis-assisted direct deposition of plasmonic core–shell structured Ag-SiO2 nanoparticles produced in the gas phase, on temperature-controlled inexpensive glass substrates. The high-performance SERS substrates were fabricated at a laboratory production rate of 100 samples/hour, demonstrating the scalability and cost-effectiveness of our aerosol manufacturing strategy. Our highly sensitive SERS substrates rapidly and quantitatively detected pesticide residues in fresh orange, indicating their practical applicability for food safety diagnostics.
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| 10. |
- Merkl, Padryk, et al.
(författare)
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Plasmonic Coupling in Silver Nanoparticle Aggregates and Their Polymer Composite Films for Near-Infrared Photothermal Biofilm Eradication
- 2021
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 4:5, s. 5330-5339
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Tidskriftsartikel (refereegranskat)abstract
- Plasmonic nanoparticles with near-IR (NIR) light absorption are highly attractive in biomedicine for minimally invasive photothermal treatments. However, these optical properties are typically exhibited by plasmonic nanostructures with complex, nonspherical geometries that may prohibit their broad commercialization and further integration into photothermal devices. Herein, we present the single-step aerosol self-assembly of plasmonic nanoaggregates that consisted of spherical silver nanoparticles with tunable extinction from visible to NIR wavelengths. This tunable extinction was achieved by the addition of SiO2 during the flame synthesis of the nanoparticles, which acted as a dielectric spacer between the spherical silver nanoparticles and was also computationally validated by simulating the extinction spectra of similar silver nanoaggregates. These plasmonic nanoaggregates were easily deposited on silicone polymeric surfaces and further encased with a top polymer layer, forming plasmonic photothermal nanocomposite films. The photothermal properties of the NIR nanocomposite films were utilized to eradicate the established biofilms of clinically relevant Escherichia coli and Staphylococcus aureus, with a relationship observed between the final surface temperature and biofilm eradication.
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| 11. |
- Sotiriou, Georgios A., et al.
(författare)
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Hybrid, Silica-Coated, Janus-Like Plasmonic-Magnetic Nanoparticles
- 2011
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 0897-4756 .- 1520-5002. ; 23:7, s. 1985-1992
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Tidskriftsartikel (refereegranskat)abstract
- Hybrid plasmonic-magnetic nanoparticles possess properties that are attractive in bioimaging, targeted drug delivery, in vivo diagnosis, and therapy. The stability and toxicity, however, of such nanoparticles challenge their safe use today. Here, biocompatible, SiO(2)-coated, Janus-like Ag/Fe(2)O(3) nanoparticles are prepared by one-step, scalable flame aerosol technology. A nanothin SiO(2) shell around these multifunctional nanoparticles leaves intact their morphology and magnetic and plasmonic properties but minimizes the release of toxic Ag(+) ions from the nanosilver surface and its direct contact with live cells. Furthermore, this silica shell hinders flocculation and allows for easy dispersion of such nanoparticles in aqueous and biological buffer (PBS) solutions without any extra fiinctionalization step. As a result, these hybrid particles exhibited no cytotoxicity during bioimaging and remained stable in suspension with no signs of agglomeration and sedimentation or settling. Their performance as biomarkers was explored by selectively binding them with live tagged Raji and HeLa cells enabling their detection under dark-field illumination. Therefore, these SiO(2)-coated Ag/Fe(2)O(3) nanoparticles do not exhibit the limiting physical properties of each individual component but retain their desired functionalities facilitating thus, the safe use of such hybrid nanoparticles in bioapplications.
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| 12. |
- Sotiriou, Georgios A., et al.
(författare)
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Nanosilver on nanostructured silica : Antibacterial activity and Ag surface area
- 2011
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 170:2-3, s. 547-554
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Tidskriftsartikel (refereegranskat)abstract
- Nanosilver is one of the first nanomaterials to be closely monitored by regulatory agencies worldwide motivating research to better understand the relationship between Ag characteristics and antibacterial activity. Nanosilver immobilized on nanostructured silica facilitates such investigations as the SiO2 support hinders the growth of nanosilver during its synthesis and, most importantly, its flocculation in bacterial suspensions. Here, such composite Ag/silica nanoparticles were made by flame spray pyrolysis of appropriate solutions of Ag-acetate or Ag-nitrate and hexamethyldisiloxane or tetraethylorthosilicate in ethanol, propanol, diethylene glucolmonobutyl ether, acetonitrile or ethylhexanoic acid. The effect of solution composition on nanosilver characteristics and antibacterial activity against the Gram negative Escherichia coli was investigated by monitoring their recombinantly synthesized green fluorescent protein. Suspensions with identical Ag mass concentration exhibited drastically different antibacterial activity pointing out that the nanosilver surface area concentration rather than its mass or molar or number concentration determine best its antibacterial activity. Nanosilver made from Ag-acetate showed a unimodal size distribution, while that made from inexpensive Ag-nitrate exhibited a bimodal one. Regardless of precursor composition or nanosilver size distribution, the antibacterial activity of nanosilver was correlated best with its surface area concentration in solution. (C) 2011 Elsevier B.V. All rights reserved.
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| 13. |
- Sotiriou, Georgios A., et al.
(författare)
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Non-Toxic Dry-Coated Nanosilver for Plasmonic Biosensors
- 2010
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 20:24, s. 4250-4257
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Tidskriftsartikel (refereegranskat)abstract
- The plasmonic properties of noble metals facilitate their use for in vivo bio-applications such as targeted drug delivery and cancer cell therapy. Nanosilver is best suited for such applications as it has the lowest plasmonic losses among all such materials in the UV-visible spectrum. Its toxicity, however, can destroy surrounding healthy tissues and thus, hinders its safe use. Here, that toxicity against a model biological system (Escherichia coli) is "cured" or blocked by coating nanosilver hermetically with a about 2 nm thin SiO(2) layer in one-step by a scalable flame aerosol method followed by swirl injection of a silica precursor vapor (hexamethyldisiloxane) without reducing the plasmonic performance of the enclosed or encapsulated silver nanoparticles (20-40 nm in diameter as determined by X-ray diffraction and microscopy). This creates the opportunity to safely use powerful nanosilver for intracellular bio-applications. The label-free biosensing and surface biofunctionalization of these ready-to-use, non-toxic (benign) Ag nanoparticles is presented by measuring the adsorption of bovine serum albumin (BSA) in a model sensing experiment. Furthermore, the silica coating around nanosilver prevents its agglomeration or flocculation (as determined by thermal annealing, optical absorption spectroscopy and microscopy) and thus, enhances its biosensitivity, including bioimaging as determined by dark field illumination.
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| 14. |
- Teleki, Alexandra, et al.
(författare)
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Highly scalable production of uniformly-coated superparamagnetic nanoparticles for triggered drug release from alginate hydrogels
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:26, s. 21503-21510
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Tidskriftsartikel (refereegranskat)abstract
- Intelligent, on-demand drug administration systems with controlled release kinetics may revolutionize the way diseases are treated. Typically, the release of the therapeutic payload from these systems is activated by stimuli-responsive nanofillers. However, limitations regarding large-scale nanomaterial production and poor reproducibility keep such systems in the labs and away from clinics. Here, we demonstrate the highly scalable and reproducible synthesis of uniform superparamagnetic Fe2O3 nanoparticles coated with a nanothin layer of amorphous SiO2, and evaluate their suitability as stimuli-responsive nanofillers in a drug-loaded biopolymer alginate matrix. The superior colloidal stability of the SiO2-coated Fe2O3 nanoparticles over their uncoated counterparts and their dispersibility in aqueous suspensions facilitates their incorporation in alginate hydrogel microbeads. We examine the hyperthermia performance of such multiscale particle structures in the presence of alternating magnetic fields and compare the release of dextran (a model biomolecule) in the presence and absence of external stimuli. The enhanced triggered release of dextran in the presence of magnetic fields further highlights the potential of such superparamagnetic SiO2-coated Fe2O3 nanoparticles as a functional transducer in such systems.
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| 15. |
- Ziesmer, Jill, et al.
(författare)
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Highly Efficient Near-IR Photothermal Microneedles with Flame-Made Plasmonic Nanoaggregates for Reduced Intradermal Nanoparticle Deposition
- 2022
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Ingår i: Advanced Materials Interfaces. - : Wiley. - 2196-7350. ; 9:34
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Tidskriftsartikel (refereegranskat)abstract
- Near-infrared (NIR) photothermal therapy by microneedles (MNs) exhibits high potential against skin diseases. However, high costs, photobleaching of organic agents, low long-term stability, and potential nanotoxicity limit the clinical translation of photothermal MNs. Here, photothermal MNs are developed by utilizing Au nanoaggregates made by flame aerosol technology and incorporated in water-insoluble polymer matrix to reduce intradermal nanoparticle (NP) deposition. The individual Au interparticle distance and plasmonic coupling within the nanoaggregates are controlled by the addition of a spacer during their synthesis rendering the Au nanoaggregates highly efficient NIR photothermal agents. In situ aerosol deposition of Au nanoaggregates on MN molds results in the fabrication of photothermal MNs with thin plasmonic layers. The photothermal performance of these MN arrays is compared to ones made by three methods utilizing NP dispersions, and it is found that similar temperatures are reached with 28-fold lower Au mass due to reduced light scattering losses of the thin layers. Finally, all developed photothermal MN arrays here cause clinically relevant hyperthermia at benign laser intensities while reducing intradermal NP deposition 127-fold compared to conventional MNs made with water-soluble polymers. Such rational design of photothermal MNs requiring low laser intensities and minimal NP intradermal accumulation sets the basis for their safe clinical translation.
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