FRESH bioprinting of biodegradable chitosan thermosensitive hydrogels

Thermosensitive chitosan (CH)-based hydrogels prepared with a mix of sodium bicarbonate and ?-glycerophosphate as gelling agents rapidly pass from liquid at room temperature to mechanically strong solid body without any crosslinker. They show excellent potential for tissue engineering applications could be interesting candidates bioprinting. Unfortunately, since gelation is not instantaneous, formulations compatible cell encapsulation (chitosan concentrations around 2% or lower) lead very poor resolution fidelity due filament spreading. Here, we investigate the FRESH bioprinting approach warm sacrificial support bath, overcome these limitations enhance their bioprintability. First, made Pluronic including chloride salt rheology modifier agent, was designed meet specific physical state requirements (solid 37 °C temperature) rheological properties appropriate This bath presented yield stress over 100 Pa, shear thinning behavior, fast self-healing during cyclic recovery tests. Three different (CH2%w/v, CH3%w/v, mixture CH gelatin) were tested ability form 3D structures, bath. Both mechanical printed structure drastically enhanced using method, an approximate four fold decrease diameter which close needle diameter. The structures easily harvested altering shape by cooling down do swell when immersed in PBS. Live/dead assays confirmed that viability encapsulated mesenchymal stem cells highest CH2% bath-assisted process did adversely impact viability. study demonstrates FRESH-like enhances thermosensitive biodegradable opens up wide range models engineering.