Porous Elastic Composite Scaffolds Based on Enzymatically Synthesized Poly(Glycerol Adipate) and Bioglass: The Effect of L-Lysine Diisocyanate Content on Crosslinking Degree on Mechanical Properties

In this research, poly(glycerol adipate) prepolymer (pPGA) was synthesized using enzymatic polymerization of divinyl adipate (DVA) and glycerol in a reaction carried out in the presence of the enzyme Lipase B from a Candida Antarctica. The pPGA was then solved in 1,4-dioxane and reacted with L-lysine diisocyanate (LDI), then mixed with bioglass, poured into a mold with sodium chloride, cured, and freeze-dried. A novelty of this work is the use of LDI, which plays a dual role: it is a cross-linking agent and also a bioactive agent that is chemically bound to the polymer network of the scaffold. Three types of porous composite scaffolds having 20 wt.% of bioglass and different cross-linking degrees (25, 50 and 100 mol% of LDI) were investigated. The scaffolds were characterized by means of porosity, density, and morphology. All tested materials were subjected to a quasi-tatic compression test. Each material was compressed 10 times. It was shown that the materials exhibited a return to their original shape even with a large compression strain of 90%. An imaging study of the scaffolds before and after compression was conducted using computed tomography (CT). The CT study showed that the resulting materials were not significantly mechanically damaged in the multi-ompression process.