Exploration of Atmospheric Pressure Plasma Nanofilm Technology for Straightforward Bio‐Active Coating Deposition: Enzymes, Plasmas and Polymers, an Elegant Synergy

Abstract

While protein or enzyme immobilization methodologies are readily applicable in a majority of industrial processes, some lacunas still remain. For example, the multi-step, wet-chemical nature of current immobilization reactions limits straightforward bio-film fabrication in continuous production units. As such, a fast and preferably single step immobilization technique, minimizing solvent use and decoupling deposition substrate from used method is awaited. In this research, an atmospheric pressure plasma reaction environment is chosen for its flexibility in terms of reactivity and the ease of coating depositions on a wide variety of substrates. Organic coating precursors such as acetylene or pyrrole are injected simultaneously with an atomized enzyme solution directly in the discharge. By atomizing the enzyme solution, the enzyme molecules are surrounded by a watery shell. It is envisioned that such droplet act as ''shuttles'', delivering the enzymes to the discharge while protecting them from the harsh plasma conditions. In the discharge, polymerization of the added organic coating precursor takes place and consequently, the enzyme molecules become trapped in the growing polymer network. In addition, atomization of the protein solution favors the spatial distribution of the proteins in the coating. Several enzymes are evaluated and enhanced temperature and solvent stability is observed. Moreover, single molecule fluorescence, enzyme activity and bio-recognition experiments demonstrate protein integrity after plasma assisted immobilization.

Atmospheric Pressure Low Temperature Direct Plasma Technology: Status and Challenges for Thin Film Deposition

“…Beside the different considerations that can be helpful in evaluating the utilization of precursors in form of vapor or liquid as a function of the properties of the coatings to be deposited, it is beyond dispute that aerosol‐assisted processes are particularly convenient, and can even offer the only possible solution, in the following specific cases: When non‐volatile (and eventually thermolabile) precursors are utilized. If the precursor vapor pressure is very low as in the case of octamethylcyclotetrasiloxane4, 98, 99 polymethyldisiloxane;100 this avoids the heating of the precursor delivery system as required for PECVD processes. When biomolecules are injected in the discharge, as reported by Heyse et al101 for bio‐functional film fabrication. In this work, organic coating precursors, such as acetylene or pyrrole, are injected simultaneously with an atomized enzyme water solution directly in the discharge.…”

“…First, Badyal and co‐workers4, 95 developed a polymerization process at atmospheric pressure in which a He GDBD was combined with the aerosol of a liquid precursor injected through an ultrasonic mozzle integrated in the ground electrode of the discharge cell; afterwards several groups reported the employment of aerosol for the deposition of functional coating 3, 95–103. Utilizing acrylic acid as precursor, Badyal and co‐workers95 demonstrated the possibility of obtaining a high retention of the precursor carboxylic acid group in the coatings.…”

“…When biomolecules are injected in the discharge, as reported by Heyse et al101 for bio‐functional film fabrication. In this work, organic coating precursors, such as acetylene or pyrrole, are injected simultaneously with an atomized enzyme water solution directly in the discharge.…”

The 2017 Plasma Roadmap: Low temperature plasma science and technology

“…One of the most interesting categories of plasma processes developed in the last few years, for example, uses atmospheric pressure plasmas fed with aerosols of a solution of biomolecules [69] and leads to thin 'nano/bio-composite' coatings of an organic or inorganic matrix with embedded biomolecules (enzymes, drugs, saccharides, etc). When deposited in properly optim ized conditions, these coatings can release the biomolecule in a controlled way in solutions or in contact with a biological tissue, in several possible biomedical applications.…”

Wettability and Other Surface Properties of Modified Polymers

“…In the development of, e.g., biomarkers and biosensors or in molecular design, nanoparticles are very often applied [88][89][90]. These may be prepared from organic materials (e.g., polymers) and inorganic materials (e.g., metal nanoparticles).…”