Photocrosslinkable hyperbranched polyglycerol (HPG)-based bioink for 3D printing of soft tissue constructs

Abstract

Hyperbranched polyglycerol (HPG) is a branched polymer consisting of ethylene glycol backbone and hydroxyl terminal groups. It is increasingly utilized in biomedical applications due to the facile synthesis, hydrophilicity, and biocompatibility. Herein, the terminal hydroxyl groups are modified with acrylic functional groups to impart radical crosslinking. With the abundance of hydroxyl groups, the degree of acrylate substitution (DS) per HPG molecule can be easily controlled. The resulting acrylic hyperbranched polyglycerol (AHPG) could be used as a crosslinker to fabricate hydrogels with various gel-forming macromers via photoinitiated radical crosslinking reaction. The mechanical properties of the hydrogels could be controlled in a wide range by tuning the DS of AHPG, without the need to change the concentration. The in vitro cell culture studies have also demonstrated the biocompatibility of this AHPG-linked hydrogels. The suitability of this AHPG-linked hydrogel system as a 3D printing bioink to develop scaffold materials for tissue engineering applications was demonstrated by utilizing a DLP (digital light processing)-based 3D printer to generate cell-laden hydrogel constructs with varying size and shape with micron-scale resolution.