This SBIR Phase I project addresses the unacceptable incidence of orthopedic device-related infections, as well as the dangerous rise of antibiotic resistant bacteria. More than 100,000 implanted orthopedic fixation devices (pins, plates, and screws) acquire bacterial infections each year in the US, accounting for approximately $1.5 trillion in associated medical and surgical treatment costs. Furthermore, the overuse and misuse of antibiotics to treat these infections has led to a dramatic rise in antibiotic resistance, which poses a severe risk to human health. This project aims to develop and optimize a commercially viable process to impart orthopedic fixation devices with a unique surface nanotexture designed to inhibit bacterial attachment and disrupt the biofilm cycle while simultaneously stimulating robust implant integration with adjacent bone. Importantly, this treatment acts via topography alone and does not incorporate antimicrobial agents or pharmaceuticals. Due to the ubiquity and gravity of the infection epidemic, this first-of-its-kind antibacterial surface technology is expected to rapidly infiltrate the orthopedic device market and drive a dramatic market shift towards the development of products with enhanced biological activity. Ultimately, this project has the potential to alleviate significant clinical and economic burdens while stimulating technological advances in a competitive market. The proposed work aims to create an antibacterial surface nanotexture by utilizing a proprietary modified atomic deposition technique. The fabrication parameters used during this deposition process are closely linked to the resulting surface characteristics (and thus its antimicrobial efficacy). However, the link between fabrication parameters and antimicrobial efficacy is inadequately understood currently. Therefore, the proposed work employs a systematic strategy to elucidate the relationships involved and establish control over the fabrication process and resulting surface properties. The project is separated into four stages, each designed to explore the effect of a specific fabrication parameter on performance outcomes, including bacterial colonization, bone cell functions, and trends in certain surface properties that often correlate with cell-substrate interactions (e.g. surface energy, roughness, skewness, etc.). The relationships revealed through testing will be used to build a set of equations that describe how the properties of the nanotextured surface vary as a function of the fabrication parameters. This set of equations will then be used to optimize the system, enabling consistent and controllable operation of the deposition process as manufacturing specifications evolve. In addition to advancing the development of a market-changing product, the proposed research will contribute to the growing understanding of cell and bacteria responses on nanostructured surfaces in an ongoing effort to mitigate infection associated with orthopedic implants.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
