The Food & Drug Administration (FDA) requires that manufacturers assure the safety of medical devices or products that contact body tissues/fluids. Therefore, it is vital to minimize the release of chemical species, commonly known as leachables and extractables, from medical devices. The presence of these species may be due not only to the chemical composition of the materials, but also from manufacturing processes. Leachables and extractables from medical device biomaterials may have a significant impact on biocompatibility and may pose significant risks to patient health. This project will minimize the release of leachables from several classes of common biomaterials, including (a) polyvinylchloride (used in intravenous tubing and blood storage bags), (b) additively manufactured polyetheretherketone (used in bone implants), and (c) nickel-titanium shape memory alloy (used in cardiovascular stents for vessel patency), by depositing hydrogenated diamond-like carbon (DLC) coatings on the surfaces of these materials. DLC is a material made up entirely of carbon atoms, it can serve as a cell-friendly permeation barrier that prevents the release of leachables. This inexpensive technology has been utilized to prevent oxygen permeation in the bottled beverage industry. A DLC coating that would be chemically-amenable on polymers or metal alloys used in medical devices would reduce leachable-associated health risks across many classes of materials.
The project has three aims. Aim 1: Deposition of DLC coatings on model biomaterials using plasma enhanced physical vapor deposition and physico-chemical characterization of the coatings. Scanning electron microscopy will be used to confirm the absence of pinholes in the coating, to confirm the coating thickness, and to evaluate the surface morphology. Aim 2: Chemical characterization and toxicological risk assessment of extractables and leachables from uncoated and DLC-coated biomaterials under physiologic and worst-case conditions. The milestone for this deliverable will be a comparison of the release of extractables and leachables from the DLC coated materials compared to uncoated materials. A toxicologic hazard identification assessment will be conducted to determine if any of the materials pose a toxicological risk. Aim 3: Biocompatibility testing of extractables/leachables from coated and uncoated/DLC-coated biomaterials using in vitro assays. The extractables and leachables from both uncoated and DLC-coated biomaterials will be used to treat mammalian cells in vitro for assessment of cell viability, reactive oxygen species (ROS) production, and pro-inflammatory cell markers. The goal is to confirm if DLC coatings reduce extractables/leachables from biomaterials that are commonly used in medical devices. If the proposed project is successful, the medical device industry will have a material (DLC) for application to a wide variety of metals and polymers.
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.
