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Cold atmospheric pressure (CAP) plasma for the deactivation of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) spike protein binding to ACE2 protein.

Self-assembly of proteins after CAP treatment.

Atmospheric pressure non-thermal plasma jets are becoming subject of great attention in various fields such as plasma processing and biomedical applications due to their ability to produce highly reactive species and good reaction chemistry at low gas temperatures. In the present study, a non-thermal plasma jet operating on argon gas at atmospheric pressure aimed mainly towards surface modification and thin film deposition applications has been developed. Optical emission spectroscopy is used to evaluate the plasma parameters. The gas temperature (800 ± 50 K) is estimated from OH(A-X) rotational band. The excitation temperature is measured using intensity ratio of two argon lines and is found to be 0.241–0.273 eV and the corresponding electron temperatures have been measured. Electron density of the order of 1014 cm−3 has been obtained from the Stark broadening of Balmer H β line. The plasma jet has been successfully employed to deposit a superhydrophobic thin film of SiwCxHyOz using hexamethyldisiloxane (HMDSO) precursor monomer. The deposited film has been analyzed using XRD, FTIR, SEM, AFM, and contact angle analyzer. All the treated surfaces have shown superhydrophobic property with a contact angle greater than 150° showing numerous potential in various applications. This method is a relatively easy and environmental friendly way of fabricating superhydrophobic surfaces.

Cold plasma generated in an open environment with a temperature nearly around room temperature has recently been a topic of great importance. It has unlocked the door of plasma application in a new direction: biomedical applications. Cold atmospheric pressure (CAP) plasma comprises various neutral and charged reactive species, UV radiations, electric current/fields etc., which have several impactful effects on biological matter. Some of the significant biological effects of CAP plasma are inactivation of microorganism, stimulation of cell proliferation and tissue regeneration, destruction of cells by initializing apoptosis etc. Although the detailed mechanism of action of plasma on biomaterials is still not completely understood, some basic principles are known. Studies have indicated that the reactive oxygen species and nitrogen species (ROS, RNS) play a crucial role in the observed biological effects. In this perspective, this chapter first provides a brief discussion on the fundamentals of CAP plasma and its generation methods. Then a discussion on the optical diagnostics methods to characterize the plasma is provided. Optical emission spectroscopy (OES) is used to identify the reactive species and to measure their relative concentration. Other important plasma parameters such as gas temperature, electron/excitation temperature and electron density measurement methods using OES have also been discussed. Then a discussion on the application of CAP plasma in biomedical field is provided. A thorough understanding of biochemical reaction mechanisms involving highly reactive plasma species will further improve and extend CAP plasma technology in biomedical applications.