Antibiotic-releasing porous polymethylmethacrylate/gelatin/antibiotic constructs for craniofacial tissue engineering

An antibiotic-releasing porous polymethylmethacrylate (PMMA) construct was developed to maintain the bony space and prime the wound site in the initial step of a two-stage regenerative medicine approach toward reconstructing significant bony or composite craniofacial tissue defects. Porous PMMA constructs incorporating gelatin microparticles (GMPs) were fabricated by the sequential assembly of GMPs, the antibiotic colistin, and a clinically used bone cement formulation of PMMA powder and methylmethacrylate liquid. PMMA/gelatin/antibiotic constructs with varying gelatin incorporation and drug content were investigated to elucidate the relationship between material composition and construct properties (porosity and drug release kinetics). The porosity of PMMA/gelatin/antibiotic constructs ranged between 7.6 ± 1.8% and 38.4 ± 1.4% depending on the amount of gelatin incorporated and the drug solution added for gelatin swelling. The constructs released colistin over 10 or 14 days with an average release rate per day above 10 μg/ml. The porosity and in vitro colistin release kinetics of PMMA/gelatin/antibiotic constructs were tuned by varying the material composition and fabrication parameters. This study demonstrates the potential of gelatin-incorporating PMMA constructs as a functional space maintainer for both promoting tissue healing/coverage and addressing local infections, enabling better long-term success of the definitive regenerated tissue construct.