UC Riverside

Biodegradable medical devices provide a promising strategy to achieve temporary therapeutic functions without requiring surgical removal. Among biodegradable materials, magnesium (Mg) stands out for its favorable biocompatibility, mechanical properties, and complete resorbability. However, its rapid degradation in physiological environments significantly restricts its in vivo application. This dissertation focuses on the development of polymer-coated Mg-based devices designed to overcome this limitation and fulfill application-specific functional requirements.Three device platforms were developed by integrating Mg substrates with functional polymer coatings—conductive poly(3,4-ethylenedioxythiophene) (PEDOT) and/or elastomeric poly(glycerol sebacate) (PGS). PEDOT provides electrical conductivity and corrosion resistance, while PGS reduces mechanical mismatch, protect PEDOT from breaking and serves as a drug-loading matrix. Each device was tailored to a distinct biomedical application and evaluated through characterization as well as in vitro and in vivo studies.First, PEDOT/PGS-coated Mg microelectrodes were fabricated for temporary neural recording. The multilayer structure ensured both electrochemical stability and biocompatibility. The electrodes maintained low impedance at neural recording frequencies and supported the growth of human neural stem cells in vitro. Implantation into the mouse hippocampus confirmed effective degradation control and acceptable immune response.Second, biodegradable intra-arterial drug delivery (IADD) devices were developed to deliver localized therapeutics to downstream organs. Mg served as the structural core, while drug-loaded PGS enabled sustained release of dexamethasone (DEX) and cisplatin (CIS). In vitro studies confirmed low cytotoxicity and consistent 30-day drug release. In vivo rat models demonstrated significant improvements in focal drug concentrations—up to 68-fold increases in normalized organ drug levels compared to oral administration—while minimizing systemic exposure.Third, a PEDOT/PGS-coated Mg spinal patch was designed for spinal cord contusion treatment. The device provided mechanical support and electrical functionality to promote regeneration. The coating system protected Mg from premature degradation and supported neural stem cell adhesion and proliferation. In vitro cytocompatibility with BMSCs and HNSCs confirmed favorable in vitro performance.Overall, this work establishes polymer-coated Mg as a modular and biodegradable platform for neural, vascular, and spinal applications. The integration of material design, device fabrication, and functional testing provides a foundation for the translational potential of temporary biomedical implants.