Optomechanically Actuated Hydrogel Platform for Cell Stimulation with Spatial and Temporal Resolution

Cells exist in the body in mechanically dynamic environments,yetthe vast majority of in vitro cell culture is conductedon static materials such as plastic dishes and gels. To address thislimitation, we report an approach to transition widely used hydrogelsinto mechanically active substrates by doping optomechanical actuator(OMA) nanoparticles within the polymer matrix. OMAs are composed ofgold nanorods surrounded by a thermoresponsive polymer shell thatrapidly collapses upon near-infrared (NIR) illumination. As a proofof concept, we crosslinked OMAs into laminin-gelatin hydrogels, generatingup to 5 & mu;m deformations triggered by NIR pulsing. This responsewas tunable by NIR intensity and OMA density within the gel and isgeneralizable to other hydrogel materials. Hydrogel mechanical stimulationenhanced myogenesis in C2C12 myoblasts as evidenced by ERK signaling,myocyte fusion, and sarcomeric myosin expression. We also demonstraterescued differentiation in a chronic inflammation model as a resultof mechanical stimulation. This work establishes OMA-actuated biomaterialsas a powerful tool for in vitro mechanical manipulationwith broad applications in the field of mechanobiology.

Automated summary

In this study, hydrogels were transformed into mechanically active substrates by doping optomechanical actuator (OMA) nanoparticles. The response could be controlled by NIR intensity and OMA density within the gel and is applicable to other hydrogel materials. The mechanical stimulation of hydrogels enhanced myogenesis and rescued differentiation in a chronic inflammation model. The findings establish OMA-actuated biomaterials as a powerful tool for in vitro mechanical manipulation with broad applications in the field of mechanobiology.