TOWARD IMPROVED BIOCOMPATIBILTY: SLIPS INTEGRATION IN ADDITIVE MANUFACTURING OF IMPLANTS

Author

Zeba Urooj, Southern Illinois University CarbondaleFollow

Date of Award

5-1-2024

Degree Name

Master of Science

Department

Biomedical Engineering

First Advisor

Li, Hui

Abstract

This study explores the application, benefits, and challenges associated with the implementation of Slippery Liquid-Infused Porous Surfaces (SLIPS) technology with additive manufacturing, with a particular focus on healthcare highlighting its potential to enhance the performance and safety of medical devices and implants by preventing biofouling and bacterial colonization. Challenges in the complex process of manufacturing implantable devices, requiring specialized equipment and expertise, present a significant barrier to widespread use, particularly in resource-limited settings. These delicate implants are then used to perform regenerative, therapeutic, and diagnostic functionalities in patients, significantly advancing the healthcare practice. On the other hand, most of these implants experience the biofouling issue caused by a complex of bacteria and protein on the surface of the implants during operation. In this study, we developed a durable yet practical antifouling strategy by integrating SLIPS coating technique – a bioinspired ultra-repellent surface – with an advanced additive manufacturing technique. SLIPS technology utilizes a mechanism where a stable, immiscible lubricant layer is infused into a porous or textured solid substrates. The embedded lubricant layer is specifically designed to be immiscible with other liquids, preventing liquids from wetting the SLIPS-treated surface and allowing them to simply glide off. The lubricant's creation of a liquid-liquid interface, which greatly lowers adhesion and friction between the surface and any touching materials, is what causes this effect. Integrating SLIPS with 3D printing technology enables the creation of a complex, customizable surface with enhanced antifouling and self-cleaning properties. 3D structures were printed using after meticulous designing process and printing parameters so that the designs had a 200-300µm of pore size and could give a capillary wicking action. This process can streamline the overall process by providing rapid prototyping, design flexibility, customization and personalization, and integration of complex features. The fabrication process of this involves chemical vapour deposition of Trichloro (1H, 1H, 2H, 2H – Perfluorooctyl), which is a fluorinated silane compound, making the surface molecule hydrophobic and oleophobic and immersing the silanized devices into Perflourodecalin (PFD). The PFD often used in healthcare industry, acts as the lubricant layer and forms SLIPS. Our approach to characterize the SLIPS-modified samples involved testing the samples for the sliding angle defined as minimum angle of inclination at which a droplet on the surface begins to move or slide off serving as a critical measure of the surface’s repellency and effectiveness in minimizing adhesion. To further quantify our study, we inoculated the samples with S.aureus bacterium for 1, 2, 5, and 7 days and analysed them for the formation of biolfilm. Our study successfully integrates the SLIPS technology into additive manufacturing and validates the claims of SLIPS technology for its antiadhesive and antifouling properties. Additionally, long-term durability and the performance of SLIPS in real-world applications are areas of active research, with the stability and longevity of the lubricant layer being critical for maintaining its unique properties over time alongside the need for periodic maintenance. In healthcare, the biocompatibility and safety of the lubricants used in SLIPS coatings are paramount, demanding thorough testing to ensure patient safety and regulatory compliance. Moreover, the mechanical durability and resistance to wear of SLIPS coatings are crucial for their sustained effectiveness in medical applications. This study emphasizes the need for collaborative research, clinical trials, and regulatory dialogue to overcome these challenges and fully realize the potential of SLIPS technology in 3D printed implants improving medical device performance and patient safety.