# Applications of Plasma Produced with Electrical Discharges in Gases for Agriculture and Biomedicine
## 3 Review of Plasma Applications in Agriculture and Medicine
### Plasma Application in Biomedicine
#### 3.2.1 Antimicrobial Applications  
Cold atmospheric plasma (CAP) has been considered quite an effective technique for inactivation of pathogenic infections in humans and animals [166,167]. Numerous scientific attempts demonstrated that LTP treatment can lead to the structure modification of proteins, lipids of viral envelopes, and nucleic acids [168]. In 2010, [PERSON] et al. investigated the general mechanism of plasma inactivating microorganisms with the use of DBD devices for CAP generation (described in detail in [169]). In this research, the tested samples included poly(ethyleneerephthalate) (PET) films soaked in gelatin and air-dried under UV light. The discharge treatment of the sample caused a rapid decrease in the bacteriophages (\(\lambda\) phages), while total inactivation was observed after 20 s exposure. It was also found that protein DNA damage, gradually accumulating with an increase in the dose of plasma, is responsible for phage inactivation. In 2009, [PERSON] et al. published a paper that described the inactivation of human and animal airborne respiratory viruses, such as respiratory syncytial virus (RSV), human parainfluenza virus (HPIV-3), and influenza A virus subtype H5N2 [170]. Their experiment was performed within the biozone technology, with the use of a cold-oxygen plasma-jet device. Plasma-generated ozone was recognised as the main factor in the viral titre decrease in all three studied viruses. The scientists suggested that ozone inactivation of viruses occurs primarily as a result of the peroxidation of both lipids and proteins. Moreover, the viruses demonstrated extreme sensitivity to ozone radicals. Figure 4: Schematic diagram of the LTP application spectrum and observed effects in biofilms, wound, skin, cancer, and viruses, as well as implant surface treatment [166]. [PERSON] et al. reported that plasma-generated ROS/RNS species have an effect on the DNA of adenoviruses and their immunogenicity [171]. In the study, a FlatPlaSter CAP device, based on surface micro-discharge plasma electrode allowing plasma generation under ambient conditions, was used. The researchers assumed that the ROS/RNS may dissolve in the virus embedding fluid and inactivate the adenovirus afterwards. The tests also showed that 240 s plasma exposure was sufficient to significantly inhibit replication and caused a drastic reduction in adenovirus concentration. [PERSON] et al. suggested that plasma-treated solutions, such as H\({}_{2}\)O, NaCl (0.9%), and H\({}_{2}\)O\({}_{2}\) (0.3%), can assist in effective virus decontamination [168]. Together with [PERSON] et al. [172] and [PERSON] et al. [173], they describe the sensitivity of microorganisms to plasma in the form of a pyramid, in which gram-negative bacteria show the lowest resistance to plasma, and bacterial spores the highest (see [168]). The researchers found that the sensitivity of certain groups of micro bio-objects highly depends on the conditions of the treatment. Figure 5 shows that the application of LTP on bacterial cells results in protein modification, lipid peroxidation, DNA damage and cell leakage, and changes in cell morphology. The reason w these changes take place is that plasma agents cause oxidative damage to intracellular proteins, potassium, and nucleic acids. According to [168; 174; 99; 153], LTP may also cause the degradation and destruction of large protein and the peptide bonds of the cell, leading to a decrease in their enzymatic activity. The applications of LTP on bacterial biofilms are studied in [175; 176; 177]. It was assumed that the cell wall thicknesses may be correlated with the time duration of LTP treatment. Moreover, the plasma sterilants inactivate biofilms by destruction of the extracellular matrix and internal cell structure. However, ROS and RNS species could also cause undesirable effects, such as cellular component destruction and bacterial death [178]. The impact of LTP on yeast species were studied in [179; 180; 181; 182; 183].