Surface Engineering of Chemically Inert Polymers for Medical and Biomedical Applications

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Since the surface of medical use textiles and thermoplastic polymers is in contact with microorganisms, cells and biological systems, surface properties play an important role. Surface engineering of existing textiles and polymeric materials is an economical way to develop new materials to meet the rigorous requirements for medical applications and protection. For example, the majority of hospital privacy curtains are contaminated in the first week of use. Subsequently, healthcare workers touch curtains after hand washing, and then touch the patients. The curtains become a vehicle for hospital cross infection. A durable antimicrobial function on the surface of privacy curtains can help decrease the possibility of cross-infection in hospitals. The ultimate goal of this research is to develop novel approaches to durably and efficiently modify the surface of chemically inert polymeric materials for biomedical and medical applications with minimal impact on the physical properties. Within the previous NSERC DISCOVERY program, our research group has successfully developed a new non-destructive and effective surface modification technique for chemically inert thermoplastic polymers such as poly(ethylene terephthalate) (PET): surface modification by forming an interpenetrating network (IPN) of functional and substrate polymers. Such surface modification is durable except if the substrate polymer is dissolved or melted. This novel surface modification technique is easy-to-use, versatile (applicable on many thermoplastic polymers), has preserved mechanical strength of modified polymer substrates, and can achieve a high density of surface functional groups. Although the tensile strength of modified PET fabrics is well preserved, the flexibility of the modified substrate is compromised to a certain degree. To optimize the surface modification and minimize the negative impact on the flexibility of polymer substrates, essential for certain medical applications such as vascular grafts and wound care dressing, we propose to conduct fundamental research to characterize the interpenetrating network in a 3-dimensional fashion, to gain a deeper understanding of the process-structure-property relationship and to durably interlock the functional polymers (such as antibacterial polymers) onto thermoplastic polymers with a minimum of crosslinking. In addition, we will identify strategies to achieve more effective and selective antibacterial activity on medical textiles and implants, allowing fast inactivation of bacteria on medical textiles, and efficient and selective kill of bacteria on implants with minimum human cell toxicity. We anticipate that the proposed study will lead to a breakthrough in the science of surface modification of chemically inert thermoplastic polymers used as medical textiles, biomaterials, and medical devices. The results from this work can be used as tools for biomaterial scientists to devise next-generation biomaterials that can better meet the biological challenges at the tissue/blood–material interface and provide technical support to industries making personal protective equipment, biomaterials and medical devices. The study of strategies for achieving more effective antibacterial surfaces will lay a foundation for the fabrication of potent and selective biocidal PET and polyurethane used in privacy curtains, nurse uniforms and surgical drapes to minimize cross-infection, and in endoscopes and catheters for biofilm control. The proposed work will lead to the training of highly qualified personnel with interdisciplinary skills in Polymer Chemistry, Analytic Chemistry, Medical Textile and Biomaterial Science.