Following studies of bulk behavior, the morphological evolution in thin films of linear TPUs with a high content of hard segment (HS) (from 70 to 100 wt %) on annealing is investigated. In contrast to melt-quenched bulk samples, a mixed phase was obtained for as-spin-cast films, and then, on annealing, a phase-separated mesophase domain, as previously observed by scattering and TEM in bulk samples, was observed by AFM to form directly from the mixed phase. In addition to this overall phase behavior, a crystallization behavior unique to thin films was observed: samples of thickness less than 120 nm and annealed at sufficiently high temperature developed large lamellar crystal blocks. Similar crystal blocks have also been found in thin films of a TPU with a more flexible chain extender, although in this case, with the greater HS/SS compatibility of this material, the phase separation behavior was not observed at all.
Biological structures control cell behavior via physical, chemical, electrical, and mechanical cues. Approaches that allow us to build devices that mimic these cues in a combinatorial way are lacking due to there being no suitable instructive materials and limited manufacturing procedures. This challenge is addressed by developing a new conductive composite material, allowing for the fabrication of 3D biomimetic structures in a single manufacturing method based on two‐photon polymerization. The approach induces a combinatorial biostimulative input that can be tailored to a specific application. Development of the 3D architecture is performed with a chemically actuating photocurable acrylate previously identified for cardiomyocyte attachment. The material is made conductive by impregnation with multiwalled carbon nanotubes. The bioinstructive effect of 3D nano‐ and microtopography is combined with electrical stimulation, incorporating biochemical, and electromechanical cues to stimulate cells in serum‐free media. The manufactured architecture is combined with cardiomyocytes derived from human pluripotent stem cells. It is demonstrated that by mimicking biological occurring cues, cardiomyocyte behavior can be modulated. This represents a step change in the ability to manufacture 3D multifunctional biomimetic modulatory architectures. This platform technology has implications in areas spanning regenerative medicine, tissue engineering to biosensing, and may lead to more accurate models for predicting toxicity.
Controlling supramolecular self-assembly across multiple length scales to prepare gels with localised properties is challenging. Most strategies concentrate on fabricating gels with heterogeneous components, where localised properties are generated by...
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