Economical and Convenient Fabrication of Antifouling Hydrogels for Implantable Medical Devices

Hydrogels garnered special attention as a biomaterial because these soft materials can mimic the natural environment of human tissues and are compatible with the human body. Poly(2-hydroxyethyl methacrylate)-based [poly(HEMA)-based] hydrogels have been used for biomedical applications such as soft contact lenses for decades. Despite the versatile applications of poly(HEMA)-based hydrogels attributed to their excellent biological, chemical, and mechanical properties, they show poor cell attachment. The low cell attachment on this soft material is beneficial for fabricating antifouling materials. Thus, poly(HEMA)-based hydrogels have potential applications in the medical field to prevent the growth of biofilms on medical implants and devices that stay in the human body for prolonged times. When a device remains in the human body for a long time, bacteria attach to the substrate and grow into clusters of cells known as biofilms. Biofilms are thick cell masses and resistant to antibiotics, so treating biofilms-related infections is challenging. Consequently, the biofilms grown on an implant may cause detrimental issues to the patient or damage the medical device. Therefore, searching for materials that can prevent biofilms has a vital importance. This study investigates the fabrication of a HEMA-based hydrogel with antifouling properties. Surface charge and functional groups are the key factors controlling bacterial attachment to a substrate. Therefore, we synthesize copolymers by blending HEMA with monomers such as 2-(Dimethylamino)ethyl methacrylate (DMAEMA). We prepare the polymers by changing the composition of the monomers in the reaction mixture to optimize the chemical composition of the polymer. The polymer with the optimum chemical composition should restrict the attachment of bacteria while maintaining the desired chemical and mechanical properties. The crosslinked network structure of a hydrogel determines its mechanical properties and supports the mechanical integrity of the polymer. Crosslinks also allow the polymer to absorb water excessively, making high water retention a unique feature of a hydrogel. However, the number of crosslinks in the polymer regulates its water retention capacity. Therefore, we vary the number of crosslinks by changing the amount of crosslinking agent in the reaction mixture to obtain the polymer with desirable mechanical and water retention properties. Furthermore, we investigate the effect of surface charge on controlling the bacterial attachment by introducing ionic groups to vary the surface charge. Additionally, we look into the conditions that make the synthesis process more controllable. In this study, we use a thermal initiator to initiate the polymerization reaction. Since the thermal initiation does not require sophisticated instruments, our technique makes the synthesis process convenient, simple, and economical.