Bone morphogenetic protein-2 (BMP-2) plays a critical role in bone formation. The aim of this study was to compare the activity of the mammalian cell BMP-2 to the E-coli cell BMP-2. In vitro, the potency of mammalian and E-coli BMP-2 was compared by adding BMP-2 to C2C12 cells and measuring the level of alkaline phosphatase activity. In vivo, the activity was evaluated by placing the bioimplants in the thigh muscle of mice, and measuring the amount of bone induced. The in vitro assay clearly showed that mammalian BMP was significantly more potent than E-coli BMP. In vivo, on the calcium phosphate carrier, mammalian BMP produced more bone than E-coli BMP, but E-coli BMP produced higher density tissue than mammalian BMP. On both mammalian and E-coli BMP, the calcium phosphate carrier had a significant effect on the density but not the quantity of bone produced versus the absorbable collagen sponge carrier.

Bone morphogenetic protein-2 (BMP-2) plays a critical role in bone formation. The aim of this study was to compare the activity of the mammalian cell BMP-2 to the E-coli cell BMP-2. In vitro, the potency of mammalian and E-coli BMP-2 was compared by adding BMP-2 to C2C12 cells and measuring the level of alkaline phosphatase activity. In vivo, the activity was evaluated by placing the bioimplants in the thigh muscle of mice, and measuring the amount of bone induced. The in vitro assay clearly showed that mammalian BMP was significantly more potent than E-coli BMP. In vivo, on the calcium phosphate carrier, mammalian BMP produced more bone than E-coli BMP, but E-coli BMP produced higher density tissue than mammalian BMP. On both mammalian and E-coli BMP, the calcium phosphate carrier had a significant effect on the density but not the quantity of bone produced versus the absorbable collagen sponge carrier.

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.

Titanium has been used in bio-medical implants for decades due to its superior biocompatibility. To improve the osseointegration of dental and orthopaedic implants, various surface modification techniques have been used including laser surface texturing. In particular, short-pulsed lasers, such as femtosecond and picosecond lasers, are widely used for surface modification. In this thesis, commercially pure Ti surfaces are modified by a femtosecond laser to explore the relationship between surface topography, surface chemistry, surface wettability, and biocompatibility with the goal of improving the osseointegration of implants. The laser textured surfaces consist of 1μm wide grooves spaced 10 μm, 4.8 μm, 2.4 μm and 1.2 μm apart. Gradient configurations where the groove spacing varies are also investigated. Surface morphology was characterized using Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). A custom-build contact angle measurement apparatus is used to investigate the wettability of the laser textured surfaces using the sessile drop method. Freshly laser-treated commercially pure Ti surfaces are found to be super-hydrophilic and become hydrophobic over time when exposed to air. The presence of grooves can accelerate the evolution of the contact angle over time, and introduces anisotropy in the wetting behavior (along vs. across the grooves). The hydrophilicity of laser treated surfaces can be retained by storing samples in ethanol. X-ray Photoelectron Spectroscopy (XPS) shows that the relative carbon content increases over time when Ti samples are exposed to air, which results in the subsequent evolution of the contact angle and cell response to laser textured Ti surfaces. Besides, laser treatment promotes the oxidation of pure Ti, and the product, TiO2, is responsible for the better biocompatibility. In vitro experiments using MG 63s osteoblast-like cells are implemented on laser-treated Ti surfaces and polished surfaces (control) with 1 day, 3 days and 7 days of cell culture. The best cell outcome was obtained by storing samples in air for 1 week, where storing for shorter or longer times resulted in the worst outcome, especially in the early stages of cell adhesion. There does not appear to be a direct link between wettability and the fate of cells on Ti surfaces. Indeed, while samples stored in air and ethanol have drastically different contact angle measurements (the former being hydrophobic and the latter hydrophilic), the cell behavior was unaffected. In addition, while wettability and laser treatment can affect the early stages of cell adhesion, they do not have a strong effect on the number of cells at longer incubation times (3 and 7 days). Laser machining does however affect the cell morphology and alignment, where cells preferentially align themselves parallel to the direction of the laser machined grooves with an elongated morphology.