Plasma-Enhanced Chemical Vapor Deposition: Where we are and the Outlook for the Future

Chemical vapor deposition (CVD) is a technique for the fabrication of thin films of polymeric materials, which has successfully overcome some of the issues faced by wet chemical fabrication and other deposition methods. There are many hybrid techniques, which arise from CVD and are constantly evolving in order to modify the properties of the fabricated thin films. Amongst them, plasma enhanced chemical vapor deposition (PECVD) is a technique that can extend the applicability of the method for various precursors, reactive organic and inorganic materials as well as inert materials. Organic/inorganic monomers, which are used as precursors in the PECVD technique, undergo disintegration and radical polymerization while exposed to a high-energy plasma stream, followed by thin film deposition. In this chapter, we have provided a summary of the history, various characteristics as well as the main applications of PECVD. By demonstrating the advantages and disadvantages of PECVD, we have provided a comparison of this technique with other techniques. PECVD, like any other techniques, still suffers from some restrictions, such as selection of appropriate monomers, or suitable inlet instrument. However, the remarkable properties of this technique and variety of possible applications make it an area of interest for researchers, and offers potential for many future developments

Novel Honokiol-eluting PLGA-based scaffold effectively restricts the growth of renal cancer cells.

Renal Cell Carcinoma (RCC) often becomes resistant to targeted therapies, and in addition, dose-dependent toxicities limit the effectiveness of therapeutic agents. Therefore, identifying novel drug delivery approaches to achieve optimal dosing of therapeutic agents can be beneficial in managing toxicities and to attain optimal therapeutic effects. Previously, we have demonstrated that Honokiol, a natural compound with potent anti-tumorigenic and anti-inflammatory effects, can induce cancer cell apoptosis and inhibit the growth of renal tumors in vivo. In cancer treatment, implant-based drug delivery systems can be used for gradual and sustained delivery of therapeutic agents like Honokiol to minimize systemic toxicity. Electrospun polymeric fibrous scaffolds are ideal candidates to be used as drug implants due to their favorable morphological properties such as high surface to volume ratio, flexibility and ease of fabrication. In this study, we fabricated Honokiol-loaded Poly(lactide-co-glycolide) (PLGA) electrospun scaffolds; and evaluated their structural characterization and biological activity. Proton nuclear magnetic resonance data proved the existence of Honokiol in the drug loaded polymeric scaffolds. The release kinetics showed that only 24% of the loaded Honokiol were released in 24hr, suggesting that sustained delivery of Honokiol is feasible. We calculated the cumulative concentration of the Honokiol released from the scaffold in 24hr; and the extent of renal cancer cell apoptosis induced with the released Honokiol is similar to an equivalent concentration of direct application of Honokiol. Also, Honokiol-loaded scaffolds placed directly in renal cell culture inhibited renal cancer cell proliferation and migration. Together, we demonstrate that Honokiol delivered through electrospun PLGA-based scaffolds is effective in inhibiting the growth of renal cancer cells; and our data necessitates further in vivo studies to explore the potential of sustained release of therapeutic agents-loaded electrospun scaffolds in the treatment of RCC and other cancer types