VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

Stretchable Electronic Platform for Soft and Smart Contact Lens Applications

“…The TPU Platilon U4201 AU from BAYER was of particular interest for this work thanks to its similar mechanical properties compared to soft lenses, mainly based on 2‐hydroxy‐ethyl methacrylate. For instance, TPU's elastic modulus is only five times higher (10 vs 2 MPa) and their hardness are alike (Shore A87 vs Shore A85.6), whereas its maximum elongation is fifteen times higher (550% vs 43%) . Hence these akin properties assure the platform's mechanical integrity when subjected to tensile, shear and/or bending forces.…”

“…The principal strain values (Figure d) remain the same during the relaxation period (5 to 60 s), due to the mechanical constriction provided by the shape of the mold. Although the maximum tensile deformation occurs at the supporting meanders (around 3.5%), this value is well below the maximum strain limit of TPU (>500%) . Strain relaxation occurred during the demolding process (60 to 65 s), generating a mechanically stable platform with a radius of curvature of 9 mm.…”

Mechanisms for low-temperature direct bonding of Si/Si and quartz/quartz via VUV/O3 activation

“…The energy of VUV rays with a wavelength of 172 nm is 695.49 kJ mol −1 , 30 while oxygen consists of O O covalent bonds with a bond energy of 494.4 kJ mol −1 . 31 Therefore, oxygen in the atmosphere absorbs the VUV radiation and generates highly reactive atomic oxygen.…”

Bone‐forming cells with pronounced spread into the third dimension in polymer scaffolds fabricated by two‐photon polymerization

“…The two‐photon polymerization technique employed in this work is better suited to create such small structures. The problem of limited spatial resolution in conventional techniques may be overcome by cyclic mechanical straining of cell scaffolds seeded with NBDS cells, which can also be expected to promote cell differentiation . As the PETG substrates are flexible, cyclic bending of the NBDS cells in the cell scaffolds would be possible in our case, which should have an additional stimulating effect.…”

“…The stiffness of the scaffold walls and/or the collagen matrix may also play an important role for cell differentiation into the osteogenic lineage . The close contact may be promoted by hydrophilic interaction between cell surface and scaffold walls (a similar effect was observed on polymer foils) or by the increased area for unspecific focal adhesion. The chemical composition of the walls and the geometrical shape of the cell–material interface may also be important for the interaction between cells and extracellular material and for cell differentiation .…”