| 1. |
- Zhdanov, Vladimir, 1952, et al.
(författare)
-
Virions and respiratory droplets in air: Diffusion, drift, and contact with the epithelium
- 2020
-
Ingår i: BioSystems. - : Elsevier BV. - 1872-8324 .- 0303-2647. ; 198
-
Forskningsöversikt (refereegranskat)abstract
- Some infections, including e.g. influenza and currently active COVID 19, may be transmitted via air during sneezing, coughing, and talking. This pathway occurs via diffusion and gravity-induced drift of single virions and respiratory droplets consisting primarily of water, including small fraction of nonvolatile matter, and containing virions. These processes are accompanied by water evaporation resulting in reduction of the droplet size. The manifold of information concerning these steps is presented in textbooks and articles not related to virology and the focus is there frequently on biologically irrelevant conditions and/or droplet sizes. In this brief review, we systematically describe the behavior of virions and virion-carrying droplets in air with emphasis on various regimes of diffusion, drift, and evaporation, and estimate the rates of all these steps under virologically relevant conditions. In addition, we discuss the kinetic aspects of the first steps of infection after attachment of virions or virion-carrying droplets to the epithelium, i.e., virion diffusion in the mucus and periciliary layers, penetration into the cells, and the early stage of replication. The presentation is oriented to virologists who are interested in the corresponding physics and to physicists who are interested in application of the physics to virology.
|
|
| 2. |
- Höök, Fredrik, et al.
(författare)
-
Nanopartiklar kan förbättra avbildningsteknik och diagnostik
- 2017
-
Ingår i: Läkartidningen. - 0023-7205 .- 1652-7518. ; 114
-
Forskningsöversikt (refereegranskat)abstract
- Nanotechnology can improve diagnostics The unique properties of nanoparticles make them tailorable into diagnostic agents on a molecular level, which allow more sensitive and precise in vitro diagnostics and in vivo imaging. While in vitro applications already have impact on diagnostics, in vivo use remains challenging due to difficulties in preparing nanoparticles with acceptable properties regarding toxicity, specific target accumulation and degradation. This article describes the innovative work of developing such platforms, and concludes that while nanotechnology-based diagnostics and imaging are still scarce at the clinical level, the rapid development of many new concepts, devices and processes that are now in the laboratory pipeline promises significant impact in the near future.
|
|
| 3. |
- Kamp, Carl Justin, 1982, et al.
(författare)
-
Nanofabricated catalyst particles for the investigation of catalytic carbon oxidation by oxygen spillover
- 2017
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 33:20, s. 4903-4912
-
Tidskriftsartikel (refereegranskat)abstract
- The catalytic oxidation of carbon by molecular oxygen was studied using C/Pt, Pt/C, Pt/Al2O3/C, Pt/CeO2/C, Al2O3/C and CeO2/C model samples prepared by hole-mask colloidal lithography. By this technique the degree of contact between platinum and carbon was controlled with high precision. The oxidation of carbon was monitored using atomic force microscopy and scanning electron microscopy. The results show that Pt in direct contact with carbon catalyzes the oxidation of carbon by spillover of dissociated oxygen from Pt to carbon. By physically separating Pt and carbon with a 10 nm thin spacer layer of Al2O3, the oxygen spillover was entirely blocked. However, through a corresponding spacer layer of CeO2, carbon oxidation was still observed, either by oxygen spillover from Pt to carbon or directly dissociated on the ceria, although at a slower rate compared to the case with no spacer layer between Pt and carbon.
|
|
| 4. |
- Kasemo, Bengt Herbert, 1942, et al.
(författare)
-
Nanopartiklar kan förbättra avbildningsteknik och diagnostik [Nanoparticles can improve imaging and diagnostics]
- 2017
-
Ingår i: Läkartidningen. - 1652-7518 .- 0023-7205. ; 114:27-29
-
Tidskriftsartikel (refereegranskat)abstract
- The unique properties of nanoparticles make them tailorable into diagnostic agents on a molecular level, which allow more sensitive and precise in vitro diagnostics and in vivo imaging. While in vitro applications already have impact on diagnostics, in vivo use remains challenging due to difficulties in preparing nanoparticles with acceptable properties regarding toxicity, specific target accumulation and degradation. This article describes the innovative work of developing such platforms, and concludes that while nanotechnology-based diagnostics and imaging are still scarce at the clinical level, the rapid development of many new concepts, devices and processes that are now in the laboratory pipeline promises significant impact in the near future. © 2017, Swedish Medical Association. All rights reserved.
|
|
| 5. |
- Satriano, C., et al.
(författare)
-
Ferritin-supported lipid bilayers for triggering the endothelial cell response
- 2017
-
Ingår i: Colloids and Surfaces B: Biointerfaces. - : Elsevier BV. - 0927-7765 .- 1873-4367. ; 149, s. 48-55
-
Tidskriftsartikel (refereegranskat)abstract
- Hybrid nanoassemblies of ferritin and silica-supported lipid bilayers (ferritin-SLBs) have been prepared and tested for the adhesion, spreading and proliferation of retinal microvascular endothelial cells (ECs). Lipid membranes with varying surface charge were obtained by mixing cationic 1-palmitoyl-2-oleoyl-sn-glycero-3-ethylphosphocholine (POEPC) with zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at increasing POPC/POEPC ratios. The supported bilayer formation and their subsequent interaction processes with ferritin were studied at the pH of 7.4 at different protein concentrations, by using the quartz crystal microbalance with dissipation monitoring and by atomic force microscopy. Both kinetics and viscoelastic parameters of the protein-lipid membrane interface were scrutinized, as well as surface coverage. Phase-contrast optical microscopy analyses of the ferritin-SLBs substrates after their interaction with endothelial cells evidenced the highest cell adhesion (2-4 h of incubation time) and proliferation (from 24 h to 5 days) for the membranes of POPC/POEPC (75:25 ratio). Moreover, ferritin increased both cell adhesion and proliferation in comparison to control glass (respectively 1.5- and 1.75-fold) as well as proliferation in comparison to bare POPC/POEPC (95:5 ratio) (2 fold). Results are very promising in the goal of modulating the endothelial cell response through the interplay of viscoelastic/charge properties of the solid-supported membranes and the SLB-conditioned ferritin activity.
|
|
| 6. |
- Cardenas, J. F., et al.
(författare)
-
Structural Raman Enhancement in Graphite Nano-Discs
- 2016
-
Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. - 9781510601284 ; 9883, s. Article Number: 98830L-
-
Konferensbidrag (refereegranskat)abstract
- Raman scattering in disc-shaped graphite nanostructures, etched out of bulk HOPG, are investigated using an excitation wavelength of 532 nm at different laser power. The G-band is fitted using two Lorentzian functions, G(L) and G(H). The difference of Raman shift between the two Lorentzian functions increase with laser power as a consequence of selective absorption and heating of the discs. Further, the G-band from the nanostructured HOPG reveal a Raman enhancement (R-E) of similar to 2.2 and similar to 1.5 for the components associated with the discs (G(L)) and the supporting substrate (G(H)), respectively. The quantitative agreement between the experimental results and performed finite difference time domain calculations make possible to conclude that electromagnetic energy penetrates considerably into the discs from the circular periphery probably due to multiple scattering. In addition, the dependence of R-E of the G(L) component on the laser power is attributed to a temperature dependent electron-phonon coupling.
|
|
| 7. |
- Dacic, M., et al.
(författare)
-
Influence of Divalent Cations on Deformation and Rupture of Adsorbed Lipid Vesicles
- 2016
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 32:25, s. 6486-6495
-
Tidskriftsartikel (refereegranskat)abstract
- The fate of adsorbed lipid vesicles on solid supports depends on numerous experimental parameters and typically results in the formation of a supported lipid bilayer (SLB) or an adsorbed vesicle layer. One of the poorly understood questions relates to how divalent cations appear to promote SLB formation in some cases. The complexity arises from the multiple ways in which divalent cations affect vesicle substrate and vesicle vesicle interactions as well as vesicle properties. These interactions are reflected, e.g., in the degree of deformation of adsorbed vesicles (if they do not rupture). It is, however, experimentally challenging to measure the extent of vesicle deformation in real-time. Herein, we investigated the effect of divalent cations (Mg2+, Ca2+, Sr2+) on the adsorption of zwitterionic 1,2-dioleoylsn-glycero-3-phosphocholine (DOPC) lipid vesicles onto silicon oxide- and titanium oxide coated substrates. The vesicle adsorption process was tracked using the quartz crystal microbalance-dissipation (QCM-D) and localized surface plasmon resonance (LSPR) measurement techniques. On silicon oxide, vesicle adsorption led to SLB formation in all cases, while vesicles adsorbed but did not rupture on titanium oxide. It was identified that divalent cations promote increased deformation of adsorbed vesicles on both substrates and enhanced rupture on silicon oxide in the order Ca2+ > Mg2+ > Sr2+. The influence of divalent cations on different factors in these systems is discussed, clarifying experimental observations on both substrates. Taken together, the findings in this work offer insight into how divalent cations modulate the interfacial science of supported membrane systems.
|
|
| 8. |
- Fang, Zhao, 1986, et al.
(författare)
-
TiO2 nanoparticle interactions with supported lipid membranes – an example of removal of membrane patches
- 2016
-
Ingår i: RSC Advances. - 2046-2069. ; 6:94, s. 91102-91110
-
Tidskriftsartikel (refereegranskat)abstract
- There is a need for different levels of model systems for effect studies of engineered nanoparticles and the development of nanoparticle structure–activity relationships in biological systems. Descriptors for nanoparticles based on their interactions in molecular model systems may become useful to predict toxicological responses of the nanoparticles in cells. Towards this end, we report on nanoparticle-induced formation of holes in supported model membranes. Specifically, TiO2 nanoparticle – lipid membrane interactions were studied under low ionic strength, basic conditions (pH 8), using different membrane compositions and several surface-sensitive analytical techniques. It was found that for mixed POPC/POPG (PG fractions ≥ 35%) membranes on silica supports, under conditions where electrostatic repulsion was expected, the addition of TiO2 nanoparticles resulted in transient interaction curves, consistent with the removal of part of the lipid membrane. The formation of holes was inferred from quartz crystal microbalance with dissipation (QCM-D) monitoring, as well as from optical measurements by reflectometry, and also verified by atomic force microscopy (AFM) imaging. The interaction between the TiO2 nanoparticles and the PG-containing membranes was dependent on the presence of Ca2+ ions. A mechanism is suggested where TiO2 nanoparticles act as scavengers of Ca2+ ions associated with the supported membrane, leading to weakening of the interaction between the membrane and the support and subsequent removal of lipid mass as TiO2 nanoparticles spontaneously leave the surface. This mechanism is consistent with the observed formation of holes in the supported lipid membranes.
|
|
| 9. |
- Frost, Rickard, 1979, et al.
(författare)
-
Graphene Oxide and Lipid Membranes: Size-Dependent Interactions
- 2016
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 32:11, s. 2708-2717
-
Tidskriftsartikel (refereegranskat)abstract
- We have investigated the interaction of graphene oxide (GO) sheets with supported lipid membranes with focus on how the interaction depends on GO sheet size (three samples in the range of 90-5000 nm) and how it differs between small and large liposomes. The layer by-layer assembly of these materials into multilamellar structures, as discovered in our previous research, is now further explored. The interaction processes were monitored by two complementary, real time, surface-sensitive analytical techniques: quartz crystal microbalance with dissipation monitoring (QCM-D, electroacoustic sensing) and indirect nanoplasmonic sensing (INPS, optical sensing). The results show that the sizes of each of the two components, graphene oxide and liposomes, are important parameters affecting the resulting multilayer structures. Spontaneous liposome rupture onto graphene oxide is obtained for large lateral dimensions of the graphene oxide sheets.
|
|
| 10. |
- JOHANSSON, DAVID, et al.
(författare)
-
Nanoplasmonic sensing of Pb-acid and Li-ion batteries
- 2016
-
Ingår i: Presented at the 2nd International Conference on Sensors and Electronic Instrumental Advances (SEIA), Barcelona, Spain, September 22 – 23, 2016. - : INT FREQUENCY SENSOR ASSOC-IFSA. ; , s. 57-59, s. 57-59
-
Konferensbidrag (refereegranskat)abstract
- The increasing sophistication and performance of batteries are connected with more complex chemical and physical battery processes and increase the need of more direct and informative measurements, both in the R&D phase and for monitoring and control during operation of vehicles. Todays potentiometric based measurement sensors are not sufficiently accurate for optimal battery sensing. To avoid the built in wide safety margins new, more informative monitoring signals are therefore desired or needed. In this study the optical technology NanoPlasmonic Sensing (NPS) has been used to in-situ monitor the charge and discharge processes of lead-acid and Li-ion batteries. The optical signals were found to correlate well with charging/discharging of both battery technologies.
|
|
