Controlling collagen fiber microstructure in three-dimensional hydrogels using ultrasound

摘要: Type I collagen is the primary fibrillar component of extracellular matrix, and functional properties arise from variations in fiber structure. This study investigated ability ultrasound to control microstructure during hydrogel fabrication. Under appropriate conditions, exposure type polymerization altered microstructure. Scanning electron microscopy second-harmonic generation revealed decreased diameters response compared sham-exposed samples. Results mechanistic investigations were consistent with a thermal mechanism for effects on To site-specifically, high frequency, 8.3-MHz, beam was directed within center large sample producing dense networks short, thin fibrils central core gel longer, thicker fibers outside area. Fibroblasts seeded onto these gels migrated rapidly into small, circularly arranged aggregates only area, clustered fibroblasts remodeled central, ultrasound-exposed sheets. These demonstrate capability spatially pattern various microstructures an engineered tissue noninvasively, thus enhancing level complexity matrix microenvironments cellular functions achievable three-dimensional tissues.