Infection surrounding metal implants is a common and sometimes devastating cause of implant failure in a number of fields including oral, craniomaxillofacial (CMF), orthopedic, and cardiovascular surgery. These infections, which arise from the establishment of biofilms on device surfaces, not only necessitate new surgeries but in themselves present a significant threat to life and limb. New technologies that decrease microbial colonization of metal implants would reduce these infections, mitigating their severity. Affinergy has developed bifunctional affinity peptides, called interfacial biomaterials (IFBMs), that promote the attachment and retention of drugs, proteins, and cells on the surface of medical devices. Using phage display, we have identified specific peptide sequences that bind with high affinity to a number of metals and another specific set of peptide sequences that bind with high affinity to vancomycin. Linear synthesis of these sequences as a single IFBM permits the attachment of vancomycin directly to the surface of a metal implant at point-of-care. However, Affinergy's current drug delivery coatings are limited to stoichiometric interaction between a single peptide molecule and an antibiotic. To increase the amount of antibiotic loading per surface area, we have developed self-assembling peptides (SAPs) comprised of the lead parent metal-binding and vancomycin-binding peptides, which appear to assemble into higher-order nanostructures. SAPs enhance vancomycin loading on metal by 20-fold relative to IFBMs. The goal of this proposal is to use our lead SAPs to generate a three-dimensional surface coating from self-assembling affinity peptides, capable of binding and retaining significantly higher concentrations of a drug to a device surface. Our preliminary data suggests that SAPs show improved vancomycin loading and efficacy in antimicrobial assays. This research program is designed to further development of a prototype self assembling coating system, attaching vancomycin to metal at point of care.
In Aim 1, we will optimize the primary structure and formulation of the vancomycin- and metal-binding SAPs, as well as deveop a strategy for commercial scale synthesis.
In Aim 2, we will assess SAP stability in biological fluids and confirm the peptides'biocompatibility and retention of function following storage and sterilization. Finally, in Aim 3, we will characterize the in vivo antimicrobial activity of vancomycin linked to metals using our lead candidate SAP formulation. Successful completion of these aims will provide us with the data necessary to establish relationships with large medical device companies, whose resources will be leveraged to achieve Affinergy's goal of bringing an improved antimicrobial device coating system to market. In addition, the modular nature of this technology may lead to rapid development of follow-on products with SAPs for other drugs or binding materials.
Infection surrounding metal hardware is a common and sometimes devastating cause of implant failure in a number of medical fields including oral, craniomaxillofacial (CMF), orthopedic, and cardiovascular surgery. Infections arising from the establishment of pathogenic biofilms on device surfaces not only necessitate new surgeries but in themselves present a significant threat to life and limb. Bacteria established on metal hardware within a biofilm are essentially impossible to eradicate by means other than explanation. Methods that decrease infection rates associated with metal implants would clearly benefit society and significantly reduce healthcare costs. We propose to develop a self-assembling affinity peptide coating that will promote attachment of antibiotics at point of care to a wide range of metal implants to decrease microbial colonization on their surfaces.