Humidity-Triggered Relaxation of Polyelectrolyte Complexes as a Robust Approach to Generate Extracellular Matrix Biomimetic Films

Generating a biofunctional film that can mimic the extracellular matrix (ECM) in an efficient and robust technique that may have great potential for medical devices, tissue engineering, and regenerative medicines. Herein, a facile approach to generate ECM biomimetic films based on the humidity-triggered relaxation of polyelectrolyte complex (PEC) nanoparticles is reported. The poly(l-lysine) and hyaluronan are precomplexed and sprayed onto a substrate, which, via a trigger of vaporous water, can be transformed into an even and stable film. The spontaneous polymer chain interfusion (diffusion coefficient ≈1.01 × 10-9 cm2 s-1 ) under saturated humidity, allowing for the rapid reorganization (within 30 min) of film morphology and structure is demonstrated. A controllable and scalable way for the loading of diversified bioactive agents, as well as on-demand modulation of stiffness is further presented. Moreover, the high-throughput arrays and programmed patterns can be easily completed, suggesting huge potentials that surpass those of state-of-the-art methods. Combined with high efficiency and flexible functionalization, it is believed that this approach should be beneficial for extending the practical applications of PEC films, such as medical implants, chip detectors, and so on.