Search for: All records

Abstract As a model of the intestinal epithelium, intestinal stem cells (ISCs) are grown and differentiated as monolayers on materials where stochastic organization of the crypt and villi cells occurs. An allyl sulfide crosslinked photoresponsive hydrogel with a shear modulus of 1.6 kPa is developed and functionalized with GFOGER, Bm‐binder peptide ligands for monolayer growth of ISCs. The allyl sulfide chemistry allows in situ control of mechanics in the presence of growing ISC monolayers and structured irradiation affords spatial regulation of the hydrogel properties. Specifically, ISC monolayers grown on 1.6 kPa substrates are in situ softened to 0.29 kPa, using circular patterns 50, 75, and 100 µm in diameter, during differentiation, resulting in control over the size and arrangement of de novo crypts and monolayer cellularity. These photoresponsive materials should be useful in applications ranging from studying crypt evolution to drug screening and transport across tissues of changing cellular composition. Spatiotemporal softening enables control over the size and arrangement of de novo crypts within intestinal monolayers. 

Abstract Liquid crystalline elastomers (LCEs) are stimuli‐responsive materials capable of undergoing large deformations. The thermomechanical response of LCEs is attributable to the coupling of polymer network properties and disruption of order between liquid crystalline mesogens. Complex deformations have been realized in LCEs by either programming the nematic director via surface‐enforced alignment or localized mechanical deformation in materials incorporating dynamic covalent chemistries. Here, the preparation of LCEs via thiol‐Michael addition reaction is reported that are amenable to surface‐enforced alignment. Afforded by the thiol‐Michael addition reaction, dynamic covalent bonds are uniquely incorporated in chemistries subject to surface‐enforce alignment. Accordingly, LCEs prepared with complex director profiles are able to be programmed and reprogrammed by (re)activating the dynamic covalent chemistry to realize distinctive shape transformations.