| 1. |
- Luo, Yifei, et al.
(författare)
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Technology Roadmap for Flexible Sensors
- 2023
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Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
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Forskningsöversikt (refereegranskat)abstract
- Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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| 2. |
- Fang, Zhao, 1986, et al.
(författare)
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TiO2 nanoparticle interactions with supported lipid membranes – an example of removal of membrane patches
- 2016
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Ingår i: RSC Advances. - 2046-2069. ; 6:94, s. 91102-91110
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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.
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| 3. |
- Kunze, Angelika, 1978, et al.
(författare)
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Ion-mediated changes of supported lipid bilayers and their coupling to the substrate. A case of bilayer slip?
- 2011
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-6848 .- 1744-683X. ; 7:18, s. 8582-8591
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Tidskriftsartikel (refereegranskat)abstract
- Ion-mediated (Ca(2+)) changes in viscoelastic, structural and optical properties of negatively charged solid supported lipid bilayers (SLBs) on SiO(2) surfaces were studied by means of quartz crystal microbalance with dissipation (QCM-D) monitoring and optical reflectometry. Despite the sensitivity of QCM-D to viscoeleastic/structural variations, it has not often been used to probe such changes for SLBs. SLBs were prepared from binary phospholipid mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC, neutral) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG, negatively charged) on SiO(2) sensor surfaces in a Ca(2+)-containing buffer. Interestingly, for bilayers containing POPG fractions above 35%, large QCM-D dissipation shifts occurred, when Ca(2+) was removed from buffer in contact with the SLB (while maintaining 100 mM NaCl). The accompanying frequency changes were small. These Ca(2+) mediated QCM-D responses are reversible, and a signal for considerable changes in the viscoelastic and structural properties of the SLB. Variation of Ca(2+)-concentration revealed a threshold concentration of around 0.4 mM for the changes in the SLB to occur. Below this value, at >35% POPG concentration in the SLB, the SLB appears to become more weakly attached to the SiO(2) substrate, which is partly attributed to a weakening of the POPG-substrate interaction in the absence of Ca(2+). A consequence of this is an oscillation-amplitude dependent dissipation, which we attribute to slip of the bilayer at higher oscillation amplitudes. Complementary experiments using a combined QCM-D/reflectometry instrument showed that the Ca(2+)-induced changes in the viscoelastic/structural properties of the SLB are accompanied by changes in the optical properties. We discuss different scenarios to explain the observed reversible effect of Ca(2+)-ions on the dissipative and optical properties of the mixed SLBs. Based on our results we propose the observed phenomenon to be a combination of geometric changes, internal structural changes, changes in the interfacial water layer, and a slip mechanism, i.e. friction between the SLB and the substrate.
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