Plasma-Enhanced Synthesis of Bioactive Polymeric Coatings from Monoterpene Alcohols: A Combined Experimental and Theoretical Study

Abstract

This paper describes the synthesis and characterization of a novel organic polymer coating for the prevention of the growth of Pseudomonas aeruginosa on the solid surface of three-dimensional objects. Substrata were encapsulated with polyterpenol thin films prepared from terpinen-4-ol using radio frequency plasma enhanced chemical vapor deposition. Terpinen-4-ol is a constituent of tea tree oil with known antibacterial properties. The influence of deposition power on the chemical structure, surface composition, and ultimately the antibacterial inhibitory activity of the resulting polyterpenol thin films was studied using X-ray photoelectron spectroscopy (XPS), water contact angle measurement, atomic force microscopy (AFM), and 3-D interactive visualization and statistical approximation of the topographic profiles. The experimental results were consistent with those predicted by molecular simulations. The extent of bacterial attachment and extracellular polymeric substances (EPS) production was analyzed using scanning electron microscopy (SEM) and confocal scanning laser microscopy (CSLM). Polyterpenol films deposited at lower power were particularly effective against P. aeruginosa due to the preservation of original terpinen-4-ol molecules in the film structure. The proposed antimicrobial and antifouling coating can be potentially integrated into medical and other clinically relevant devices to prevent bacterial growth and to minimize bacteria-associated adverse host responses.

Plant-derived cis-β-ocimene as a precursor for biocompatible, transparent, thermally-stable dielectric and encapsulating layers for organic electronics

“…Previous investigations have demonstrated excellent cytocompatibility of thin films fabricated using plasma polymerisation from other essential oil-based precursors, e.g. terpinene-4-ol23646566.…”

Anti-bacterial surfaces: natural agents, mechanisms of action, and plasma surface modification

“…139 Importantly, tailored plasmas enable the attainment of certain objectives conventional fabrication methodologies fail to achieve, such as providing the means for one-step green synthesis of functional materials from natural precursors. [140][141][142][143][144] …”

“…Using non-equilibrium, low-temperature plasma polymerisation, Jacob and Bazaka and their colleagues demonstrated the possibility of producing solid polymer films exclusively from essential oils, including M. alternifolia and Lavandula angustifolia essential oils and their individual constituents. 141,143 Fabricated over a wide range of processing parameters, these films varied in terms of chemical composition, surface morphology, stability and mechanical properties, while displaying uniform coverage and sound adhesion to a variety of substrates, including metals, ceramics, and polymers. 185,186 Polymers fabricated from M. alternifolia oil and its major antimicrobial component terpinen-4-ol was demonstrated to be cytocompatible with a number of host cells.…”

Sustainable Life Cycles of Natural-Precursor-Derived Nanocarbons

“…41,43,44 The plasma processing environment is flexible, and it can facilitate a range of synthesis mechanisms, from precursor-driven synthesis to process-driven synthesis. 42,45,46 At lower energy doses per precursor molecule, the conditions are more conducive to the survival of the original monomer structure in the final product ( Figure 3A). 46−48 This can best be observed in lower-power plasmas operated in a pulsed mode, where short (a few microseconds) plasma discharges deliver sufficient energy to generate radicals that can then recombine into a polymer via chemical radical chain reactions during millisecond-long plasma-free periods.…”