Physikalische Hydrogele auf Polyurethan-Basis
Physical hydrogels have gained recent attention as cell substrates, since viscoelasticity or stress relaxation is a powerful parameter in mechanotransduction, which has long been neglected. We designed multi-functional polyurethanes to form physical hydrogels via a unique tunable gelation mechanism. The anionic polyurethanes spontaneously form aggregates in water that are kept in a soluble state through electrostatic repulsion. Fast subsequent gelation can be triggered by charge shielding which allows the aggregation and network building to proceed. This can be induced by adding either acids or salts, resulting in acidic (pH 4-5) or pH-neutral hydrogels, respectively. Whereas conventional polyurethane-based hydrogels are commonly prepared from toxic isocyanate precursors, the physical hydrogelation mechanism described here does not involve chemically reactive species which is ideal for in situ applications in sensitive environments. Both stiffness and stress relaxation can be tuned independently over a broad range and the gels exhibit excellent stress recovery behavior.
Polyurethane, Hydrogele, physikalische Hydrogele, Kolloidchemie, Viskoelastizität, Stressrelaxation, Stressrelaxierung, Bulkgele, Mikrogele, Mechanotransduktion, polyurethanes, hydrogels, physical hydrogels, colloidal chemistry, viscoelasticity, stress-relaxation, stress relaxation, bulk gels, microgels, mechanotransduction
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