It is essential to develop a new type of nanocomposite biomedical implant coatings that consist of bioactive ceramics and polymers, as well as customized surface characteristics. These coatings play a vital role in enhancing cell adhesion, proliferation, and interlocking at the interface between bone tissue and the implant. This development is crucial for prolonging the durability of orthopaedic implants. The utilization of combined colloidal and electrochemical processing techniques, specifically EPD and dip coating, enables the fabrication of these novel multi-component materials with relative simplicity. Additionally, they can be utilized to create nanostructures and surface topography that imitate the composition of human skeletal tissue on a nanoscale level. In addition, colloidal-electrochemical processing techniques can be easily scaled up for clinical product development and mass manufacture, unlike many regularly utilized nanotechnology processing techniques.
The absence of efficient and biocompatible dispersants and extractors is a significant obstacle to the widespread use of colloidal-electrochemical methods for fabricating novel biomaterials in EPD, as the success of this process relies on the utilization of a stable colloidal precursor. Biomimetics, sometimes known as gaining inspiration from the natural world, is one way to generating effective dispersion and extracting agents. Using this methodology, we identified novel extracting agents. These agents proved to be highly effective in extracting particles and forming composite films that combined organic and inorganic components, containing different sized of silica particles and polyvinylidene fluoride (PVDF). By extending the method, biomimetic inspiration was derived from the human digestive system, to use bile acid salts (BAS) as solubilizing, charging, dispersing and film-forming agents for the preparation of composite coatings, containing water insoluble drugs and proteins. These coatings have the potential to be utilized for targeted administration of antibiotics, thereby preventing surgical infections after implantation. Furthermore, the inclusion of BAS surfactants enables the solubilization and dispersion of hydrophobic drugs and molecules, as well as the creation of composite films with functional properties using EPD. Moreover, a novel technique is devised for the anodic EPD of alginic acid polymer (AlgH) and composite films that contain drug molecules within the AlgH matrix. This approach entailed utilizing L-arginine as an alkalizing agent to enhance the solubility of medicines that have low solubility in water. AlgH and medication molecules are dissolved in water and then deposited via anodic EPD.
Dip coating remains a challenging task when it comes to depositing high concentrations of non-toxic solvents containing high molecular weight (MW) polymers, such as poly(ethyl methacrylate) (PEMA) and poly(methyl methacrylate) (PMMA). In this study, we initially suggested the utilization of water-isopropanol as a co-solvent for dissolving high molecular weight PMMA at high concentrations. Additionally, we utilized an advanced dispersion agent to facilitate the solubilization of PEMA. It was discovered that water molecules can surround and solvate the carbonyl groups of the polymers. This technology avoided the use of noxious solvents and a protracted heating process for their elimination. In addition, these coatings have the potential to be integrated with advanced inorganic particles, such as drugs, diamond and HA, for use in biomedical applications. / Thesis / Doctor of Philosophy (PhD) / There is a need to develop new coatings and manufacturing procedures for biomedical implant materials in order to extend the lifespan of orthopaedic implants used in clinical settings and avoid the need for expensive and unpleasant revision surgeries. Bioactive coatings enhance the durability of orthopaedic implants by reducing scar tissue formation and inflammation, while also increasing the chemical and physical bond between the synthetic implant and natural bone. As bone is a natural composite material, our goal in designing replacement materials is to replicate the inherent chemical composition and structure of human bone. Electrophoretic deposition (EPD) is a manufacturing technology that holds significant potential for creating composite coatings that imitate the structure of natural bone. This approach involves the application of an electric field to deposit charged materials onto a conductive substrate. The primary challenge in the manufacturing process of materials utilizing EPD is the tendency of particles in the precursor suspension to coagulate and distribute unevenly. This ultimately results in unwanted characteristics in the final coatings. An effective method to overcome this problem is by use dispersing agents, which are tiny molecules with either positive or negative charges that disperse particles in a suspension through electrostatic repulsion, physical separation, or a mix of both. Traditional dispersing agents have proven effective in various applications; nevertheless, their toxicity renders them unsuitable for the production of biological materials. This study presents the identification of novel dispersion agents, biomedical coatings, and manufacturing techniques for creating coatings that enhance the durability of implants and possess additional functionalities, such as biosensing for disease detection.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/30373 |
| Date | January 2024 |
| Creators | Wang, Zhengzheng |
| Contributors | Zhitomirsky, Igor, Biomedical Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0021 seconds