Atmospheric Pressure Cold Plasma: A Friendly Environment for Dry Enzymes

Abstract

A comprehensive study of the interaction of cold atmospheric pressure plasmas (CAPs) with dry enzymes is conducted to identify the experimental conditions that allow preserving enzyme functionality. Glucose oxidase (GOx) dry deposits are exposed to dielectric barrier discharges fed with pure helium, helium–oxygen, and helium–ethylene mixtures. The GOx loses functionality upon exposure to He/O2 CAP due to dry etching. X‐ray photoelectron spectroscopy reveals that, in parallel with the ablation, there are modifications of the chemical structure of the surface of the enzyme deposit that decrease the etching rate and eventually lead to a “crust” with a strong resistance against the ablation, responsible of process termination. Interestingly, the customary conditions used for plasma‐enhanced chemical vapor deposition using helium–ethylene mixtures (applied voltage <1.1 kVrms and exposure time ≤10 min) are friendly for GOx. It is therefore possible to immobilize enzymes by overcoating with a plasma‐deposited thin film, fully retaining enzyme functionality.

Biomolecules from Snail mucus (Helix aspersa) conjugate Gold nanoparticles, exhibiting potential wound healing and anti-inflammatory activity

“…The N1s signal ( Figure 3D ) shows one main peak at about 400.1 eV, consistent with the presence of amine and amide groups. [41][42][43] To unveil the nature of these compounds on the AuNPs surface, ATR-FTIR and MALDI-MS analyses were performed.…”

Direct Exposure of Dry Enzymes to Atmospheric Pressure Non-Equilibrium Plasmas: The Case of Tyrosinase

“…The research in this field has received renewed impetus in recent years due to the development of atmospheric pressure (AP) plasma technology, which represents nowadays a new avenue for surface processing of materials with reduced costs and easy-to-handle apparatuses, even under open air conditions [27][28][29][30][31][32][33][34][35]. Novel strategies have been proposed for enzyme immobilization.…”

“…Indeed, they can afford the desired surface modification with easier, faster, and more cost-effective plasma processes [27,[32][33][34]. Moreover, considerable efforts have been devoted to investigate the direct interaction of AP non-equilibrium plasmas with various biomolecules (e.g., proteins and nucleic acids) both in the dry state and in aqueous solutions, focusing on many different biomedical, biotechnological, and pharmaceutical applications [28,[35][36][37][38][39][40][41][42][43][44][45].…”

“…We recently proposed a two-step immobilization procedure in which the enzyme glucose oxidase (GOx) from Aspergillus niger is first deposited on a support, and subsequently coated with a polymer layer by using atmospheric pressure plasma-enhanced chemical vapor deposition (PECVD) [35]. A systematic investigation of effects of plasma exposure on GOx functionality was carried out by evaluating the influence of the enzyme amount as well as of various process parameters (e.g., plasma excitation conditions, feed gas composition, exposure time).…”

“…We also envisaged that the proposed immobilization strategy could be applied also to other enzymes. However, each enzyme is expected to be sensitive in a peculiar way to plasma exposure during the immobilization procedure, which could produce changes and distortions in enzyme structure, and in turn, induce its partial or total inactivation [35]. To assess the versatility of our approach, the interaction of AP non-equilibrium plasmas with other enzymes needs therefore to be investigated.…”