Abstract: The present invention relates to a functionalized metallic implant comprising a metallic substrate having a covalently bound organic acid layer and a polymeric coating covalently attached thereto. The polymeric coating includes cationic, anionic, zwitterionic, and/or hydrophobic functional groups configured to associate therapeutic agents via electrostatic and/or hydrophobic interactions. Therapeutic agent release or availability is controlled as a function of surface charge, hydrophobicity, or both, enabling localized and sustained delivery in response to local biological conditions. In certain embodiments, the coating provides antibacterial activity through contact-based membrane disruption or inhibition of bacterial adhesion. In further embodiments, zwitterionic coatings exhibit pH-responsive charge behavior enabling selective loading and release of therapeutic agents.

Abstract: Collagen matrices of varying charge and cross-linking density are disclosed, and methods for preparing such collagen matrices. The cross-linking methods for collagen impart charge and allow for variable cross-linking density within the collagen device. Such variable cross-linking density imparts variable collagen resorption time, and the variable charge allows sequestering and then releasing therapeutics in a controlled manner. The techniques may be used to impact in vitro mineralization via the charged collagen platform by its interaction with rhBMP-2. The techniques can be used to create a positively charged collagen skin substitute that resists infection and supports wound closure.