In Situ Crosslinkable Polyesters For Tissue Engineering And Drug Delivery
Gyawali, Dipendra Raj
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In situ crosslinkable elastic materials are increasingly being explored for various biomedical applications such as drug delivery and tissue engineering due to their site specific nature. The creation of an in situ crosslinkable elastomer rich in pendant chemistry has been a challenge in the field of biomaterials. Herein, we have developed two new in situ biodegradable materials: poly(octamethylene maleate citrates) (POMC) and poly(poly(ethylene glycol) maleate citrate) (PPEGMC). These materials are all low molecular weight in their pre-polymeric form, which shows their potential to be used as an injectable biomaterial. The preservation of pendant carboxylic and hydroxyl groups in these polymeric networks after crosslinking were confirmed by structural and physicochemical studies. These networks are amorphous at body temperature with a Tg below 0 °C confirmed by DSC. Both materials are highly elastic and show no permanent deformation. The ultimate tensile strength and initial modulus are between 0.22 and 0.90 MPa, and 0.07 to 1.3 MP respectively. In vitro degradation studies confirmed the slower degradation rate of POMC when compared to that of PPEGMC (<60% total mass loss within 3 month period and >60% total mass loss with in 1 month period respectively). These properties can be tuned by varying the monomer molar ratio, initiator and crosslinker concentrations, and polymer concentrations while crosslinking. Photopolymerized POMC networks demonstrated good in vitro and in vivo biocompatibility. The drug and cell encapsulation ability of PPEGMC shows its potential use as an injectable material. These novel in situ hydrogel elastomers could have potential for the conjugation and encapsulation of biomolecules and for wound bandage/healing applications.