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Optogenetic control of integrin-matrix interaction
摘要： Optogenetic approaches have gathered momentum in precisely modulating and interrogating cellular signalling and gene expression. The use of optogenetics on the outer cell surface to interrogate how cells receive stimuli from their environment, however, has so far not reached its full potential. Here we demonstrate the development of an optogenetically regulated membrane receptor-ligand pair exemplified by the optically responsive interaction of an integrin receptor with the extracellular matrix. The system is based on an integrin engineered with a phytochrome-interacting factor domain (OptoIntegrin) and a red light-switchable phytochrome B-functionalized matrix (OptoMatrix). This optogenetic receptor-ligand pair enables light-inducible and -reversible cell-matrix interaction, as well as the controlled activation of downstream mechanosensory signalling pathways. Pioneering the application of optogenetic switches in the extracellular environment of cells, this OptoMatrix–OptoIntegrin system may serve as a blueprint for rendering matrix–receptor interactions amendable to precise control with light.
关键词： Optogenetics,Mechanosensing,Extracellular matrix,Cell adhesion,Integrin
更新于2025-11-21 11:24:58
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Surface Coatings Modulate the Differences in the Adhesion Forces of Eukaryotic and Prokaryotic Cells as Detected by Single Cell Force Microscopy
摘要： Single cell force microscopy was used to investigate the maximum detachment force (MDF) of primary neuronal mouse cells (PNCs), osteoblastic cells (MC3T3), and prokaryotic cells (Staphylococcus capitis subsp. capitis) from different surfaces after contact times of 1 to 5 seconds. Positively charged silicon nitride surfaces were coated with positively charged polyethyleneimine (PEI) or poly-D-lysine. Laminin was used as the second coating. PEI induced MDFs of the order of 5 to 20 nN, slightly higher than silicon nitride did. Lower MDFs (1 to 5 nN) were detected on PEI/laminin with the lowest on PDL/laminin. To abstract from the individual cell properties, such as size, and to obtain cell type-specific MDFs, the MDFs of each cell on the different coatings were normalized to the silicon nitride reference for the longest contact time. The differences in MDF between prokaryotic and eukaryotic cells were generally of similar dimensions, except on PDL/laminin, which discriminated against the prokaryotic cells. We explain the lower MDFs on laminin by the spatial prevention of the electrostatic cell adhesion to the underlying polymers. However, PEI can form long flexible loops protruding from the surface-bound layer that may span the laminin layer and easily bind to cellular surfaces and the small prokaryotic cells. This was reflected in increased MDFs after two-second contact times on silicon nitride, whereas the two-second values were already observed after one second on PEI or PEI/laminin. We assume that the electrostatic charge interaction with the PEI loops is more important for the initial adhesion of the smaller prokaryotic cells than for eukaryotic cells.
关键词： prokaryotic cells,poly-D-lysine,silicon nitride,laminin,cell adhesion,single cell force microscopy,surface coatings,polyethyleneimine,eukaryotic cells,maximum detachment force
更新于2025-11-21 11:24:58
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Homogeneous Anodic TiO <sub/>2</sub> Nanotube Layers on Ti–6Al–4V Alloy with Improved Adhesion Strength and Corrosion Resistance
摘要： Hexagonal TiO2 nanotubes (TNTs) arrays are generally fabricated on Ti-based substrates for some biomedical purposes, but the TNT layers constructed on conventionally processed Ti alloys are usually inhomogeneous because the substrates typically contain both the α and β phases. In this work, high-pressure torsion (HPT) is applied to obtain a saturated single α-phase microstructure in Ti–6Al–4V alloys via strain-induced β phase dissolution. Homogeneous anodic TNT layers with three different morphologies, one-step nanoporous, one-step nanotubular, and two-step nanoporous structures, are electrochemically fabricated on the ultrafine-grained (UFG) Ti–6Al–4V alloy substrates after HPT processing, whereas the TNT layers prepared on coarse-grained substrates are normally inhomogeneous. More notably, the TNT layers show significantly improved adhesion strength to the UFG substrate as well as better corrosion resistance compared to those on the conventionally processed Ti–6Al–4V substrates. X-ray diffraction analysis, scanning electron microscopy in combination with electron backscatter diffraction, and transmission electron microscopy indicate that the improvement is due to a larger dislocation density in the UFG substrate as well as strain-induced β phase dissolution.
关键词： high-pressure torsion,homogeneity,TiO2 nanotubes,adhesion strength,strain-induced phase transformation
更新于2025-11-21 11:03:13
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Kinetic stabilization of cellulose nanocrystals in a photocurable prepolymer for application as an adhesion promoter in UV-curable coatings
摘要： Cellulose nanocrystals (CNC) at low loading levels were shown to reinforce a photocurable coating resulting in improved adhesion. A polyether polyol containing CNC at loading levels of up to 1.8 wt% was grafted with 3-isopropenyl-α,α-dimethylbenzyl isocyanate to functionalize it with a photocurable group. The nanoparticles were kinetically stabilized in the rapidly forming prepolymer of high viscosity. Photoinitiators and a difunctional reactive diluent were added to produce optically transparent coatings and free films upon irradiation by ultraviolet (UV) light. This allowed evaluation of the effects of CNC at low loading levels in a glassy polymer matrix obtained through a rapid cure system. Incorporation of CNC nanoparticles in the polymer matrix resulted in an average improvement in adhesive strength of 154% while enhancing tensile strength by an average of 16%. The technique described could be used as a new approach to reduce adhesive failure in UV-curable coatings without sacrificing their mechanical strength.
关键词： Coatings,Nanoreinforcement,UV curing,Nanocomposite,Adhesion promoter,Cellulose nanocrystals
更新于2025-11-21 11:01:37
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Study on the Adhesion Force Between Ga-Doped ZnO Thin Films and Polymer Substrates
摘要： Flexible Ga doped ZnO (GZO) transparent conductive thin films were prepared on polycarbonate (PC) substrates at room temperature by magnetron sputtering. The adhesive property between the GZO film and the PC substrate was investigated quantitatively by the scratch test, which is designed for the quantitative assessment of the mechanical integrity of coated surfaces. The effect of the sputtering pressures on the adhesion forces for the GZO films was investigated. When the sputtering pressure varied from 0.2 to 0.5 Pa, no obvious adhesion force alteration was observed. However, when the sputtering pressure was increased to 0.7 Pa, the adhesion force was decreased. The lowest square resistance of the GZO film was 18.6 Ω/sq. Regardless of the sputtering pressure, the transmittance in the visible light was about 90%. When the sputtering pressure was 0.4 Pa, the optimal figure of merit (ΦTC) was 2.5 × 10?2 Ω?1, indicating that the optimal pressure was 0.4 Pa.
关键词： Adhesion Force,Flexibility,ZnO Transparent Conductive Film
更新于2025-09-23 15:23:52
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Investigation of nanomechanical and adhesion behavior for AlN coating and AlN/Fe2-3N composite coatings created by Active Screen Plasma Nitriding on Al 1050
摘要： This study investigated the effect of nitriding time and temperature on the mechanical properties of the composite AlN/Fe2-3N coating deposited on the pure aluminium substrate using the novel Active Screen Plasma Nitriding (ASPN) method. ASPN treatment was performed for 2, 5, 10, 15 h at temperatures of 450,500, and 550 (cid:1)C and Conventional Plasma Nitriding (CPN) treatment was carried out for 5 h at 500 (cid:1)C. All treatments were performed at the 10 KHz frequency with 80% duty cycle on the Al1050 substrate under 20%H2t80%N2 atmosphere. Phase and microstructure studies were performed using, respectively, the grazing incidence x-ray diffraction (GIXRD) system and the ?eld emission - scanning electron microscopy (FE-SEM) system equipped with energy-dispersive spectroscopy (EDS) analyzer. The mechanical strength of the coating was evaluated by the roughness, nano-hardness, nano-scratch, and adhesion strength tests performed on coated and uncoated specimens. According to the results, the uncoated Al1050 specimen, the CPN-treated specimen, and the ASPN-treated specimen had a mean nano-hardness of 0.7 ± 0.1 GPa, 10.9 ± 0.6 GPa, and 9.6 ± 0.5 GPa, respectively. It was also found that the single-phase AlN coating has a better adhesion strength and scratch strength (LC3 ? 12 N) than the composite AlN/Fe2-3N coating (LC3 ? 10 N). Examination of scratch mechanisms in hard AlN and AlN t Fe2-3N coatings deposited on a soft aluminium substrate showed that the failures in these coatings are due to tensile-type Hertzian cracks. However, as the load increases, the substrate undergoes increasing deformation and failures shift to chipping and interfacial spallation.
关键词： Adhesion strength,Active screen plasma nitriding,Pure aluminium,Conventional plasma nitriding,Scratch resistance,Nanoindentation
更新于2025-09-23 15:23:52
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Effect of plasma treatment on adhesion strength and moisture absorption characteristics between epoxy molding compound/silicon chip (EMC/chip) interface
摘要： Reliability of interface between two dissimilar materials becomes an important issue due to increasing demands of high-density integrated circuits. Most of failures of semiconductor package occur at the interface between two dissimilar materials in high temperature reflow process, thus, adhesion strength under high temperature should be investigated. In this study, an adhesion shear test jig was newly devised to measure the adhesion strength of epoxy molding compound/Si chip (EMC/chip) interface at high temperature (200 °C). In order to investigate the effect of plasma treatment on adhesion strength and moisture absorption characteristics, the number of plasma treatments was varied. Also, moisture absorption time was varied to observe the moisture uptake and degradation of adhesion strength with respect to plasma treatment number. Atomic force microscope (AFM) was analyzed to verify the surface roughness of silicon chip, and scanning electron microscopy (SEM) was used to observe cross-sectional fractured morphology after adhesion strength test. From this study, it was found that the plasma treatments affect much the adhesion strength and moisture uptake at the interface between the EMC/Chip interface.
关键词： Semiconductor package,Moisture absorption,Adhesion strength,Plasma treatment
更新于2025-09-23 15:23:52
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Impact of Substrate Characteristics on Stretchable Polymer Semiconductor Behavior
摘要： Stretchable conductive polymer films are required to survive not only large tensile strain but also stay functional after the reduction in applied strain. In the deformation process, the elastomer substrate that is typically employed plays a critical role in the response of the polymer film. In this study, we examine the role of a PDMS elastomer substrate on the ability to achieve stretchable PDPP-4T films. Specifically, we consider the adhesion and near surface modulus of the PDMS tuned through UV/ozone treatment on the competition between film wrinkling and plastic deformation. We also consider the role of PDMS tension on the stability of films under cyclic strain. We find that increasing the near-surface modulus of the PDMS and maintaining the PDMS in tension throughout the cyclic strain process promotes plastic deformation over film wrinkling. In addition, the UV/ozone treatment increases film adhesion to the PDMS resulting in significantly reduced film folding and delamination. For 20 min UV/ozone treated PDMS, we show that a PDPP-4T film RMS roughness is consistently below 3 nm for up to 100 strain cycles with a strain range of 40 %. In addition, while the film is plastically deforming, the microstructural order is largely stable as probed with grazing incidence X-ray scattering and UV-visible spectroscopy. These results highlight the importance of the neighboring elastomer characteristics on the ability to achieve stretchable polymer semiconductors.
关键词： Yield strain,Stretchable electronics,Deformability,Polymer semiconductors,Adhesion energy
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Waikoloa Village, HI, USA (2018.6.10-2018.6.15)] 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC) - Effects of Solar-Glass Coatings on the Adhesion Forces Related to Soiling
摘要： We report on the impact that different coatings on solar glass have on the adhesion forces with SiO2 spheres, which are used to emulate real dust particles. We measured the forces in an atomic force microscope, using force versus distance measurements, and performed the investigation at different values of relative humidity, from 15% to 80%. We will show that, in general, bare solar glass has the largest adhesive forces, with a strong influence of RH. In contrast, some coatings result in much lower adhesion forces and little influence of humidity, which suggests that these coatings may help reduce soiling, and have an impact on soiling associated with dew formation and some cementation processes.
关键词： coatings,adhesion forces,Soiling
更新于2025-09-23 15:23:52
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Real-time profiling Anti-EpCAM Based Immune capture, from Molecules to Cells using MP-SPR
摘要： Antibodies of epithelial cell-adhesion-molecule (anti-EpCAM)-based interfaces have proven to be highly efficient at capturing circulating tumor cells (CTCs). To achieve the bonding of anti-EpCAM to the interface, biotin and streptavidin are used to modify the surface. These processes are critical to subsequent cell-capture efficiencies. However, quantitative research on the interactions between biotin, streptavidin and biotinylated anti-EpCAM on the interface is lacking. In this work, the thermodynamics and kinetics of biomolecular interactions were determined by using surface plasmon resonance. The equilibrium binding affinities for biotinylated anti-EpCAM to streptavidin and streptavidin to biotin (illustrated by biotin-PEG400-thiol) were found to be 2.75×10^6 M^-1 and 8.82×10^6 M^-1, respectively. Each streptavidin can bind up to 2.30 biotinylated anti-EpCAM under thermodynamic equilibrium. The findings provide useful information to optimize the modification of anti-EpCAM and improve the capture efficiency of CTCs.
关键词： surface plasmon resonance,antibodies of epithelial cell-adhesion-molecule,cell capture,biotin–streptavidin interaction,thermodynamics,kinetics
更新于2025-09-23 15:23:52