(730d) Elastin-Based Scaffolds for Local Delivery of Antibiotics and Proteins

Tissue engineering applications utilizing polymeric scaffolds benefit from the sustained and controlled release of signaling molecules, growth factors for cellular proliferation, and antibiotics essential for bactericidal activity to obtain optimal healing of tissues. Elastin-like polypeptides (ELPs) are biopolymers with pentapeptide repeat unit, VPGXGwhere V = valine, P = proline, G = glycine, and X, the guest residue, is any amino acid other than proline. ELPs can be genetically engineered, providing precise control over their molecular weight and structure. They possess good biocompatibility, are biodegradable, exhibit mechanical properties similar to natural elastin, and can be further cross-linked for additional manipulation of properties. This research investigated the release profiles of a model protein (albumin) and a commonly used antibiotic in periodontal therapy (doxycycline) from ELP hydrogel scaffolds. The amount of ELP, doxycycline, or albumin released was analyzed. Both albumin and doxycycline showed a gradual time dependent release over the 500h and 200h period, respectively. Albumin had a slower rate of release from ELP as compared to doxycycline and no burst release, suggesting that molecular size and weight are key factors in determining release rate. Both doxycycline and  albumin showed a trend of higher release fractions at higher loading doses. These experiments demonstrated that ELP scaffolds, the synthetic form of elastin, can provide for sustained and controlled release of proteins and antibiotics critical to tissue engineering.