Synthesis of bio-functional nanomaterials in reactive plasma discharges

Abstract

Plasma processing technologies have been extensively used as surface modification platforms in many biomedical applications. Particularly, plasma polymerization (PP) is a versatile deposition technology which has the potential to deliver biocompatible interfaces for a myriad of medical devices. To successfully translate new materials for specific clinical applications, the plasma process needs to be scalable and incorporate appropriate control feedback strategies. However, the plasma medium in PP is exceptionally complex and identifying the main physical quantities that allow a suitable formulation and description of the interface growth mechanisms is challenging. The first part of the thesis reports the design and optimization of a single step ion assisted PP process to create plasma-activated coatings (PAC) that meet the extreme mechanical demands for cardiovascular implants and in particular stents. An ideal working window in the parameter space is identified, and found suitable for the synthesis of PAC interfaces that are mechanically robust, hemocompatibility and allow one step covalent protein immobilization without the need for chemical processes. This window is identified by combining plasma optical emission spectroscopy (OES) with a comprehensive macroscopic process description that isolates key coating growth mechanisms. During process scalability, OES diagnostics revealed the formation of plasma polymer nanoparticles (nanoP3), usually known as plasma dust, in parallel with the deposition of PAC coatings. The second part of the thesis reports the demonstration of carbonaceous plasma nanoparticles for nanomedicine applications. By controlling nanoparticle formation and collection, nanoP3 were engineered with unique immobilization capabilities facilitating multifunctional nanocarriers. The unique surface chemistry of nanoP3, allowing a robust immobilization of the cargo without the need for intermediate functionalization strategies, has great potential to overcome major limitations of currently proposed platforms. As many of the favorable characteristics of nanoP3 are inherent to the fabrication process, this work proposes PP as a nanoparticle synthesis route with valuable potential for broad clinical and commercial applications