Rapidly evolving cold atmospheric pressure plasma (CAPP)–based technology has been actively used not only in bioresearch but also in biotechnology, food safety and processing, agriculture, and medicine. High variability in plasma device configurations and electrode layouts has accelerated non-thermal plasma applications in treatment of various biomaterials and surfaces of all sizes. Mode of cold plasma action is likely associated with synergistic effect of biologically active plasma components, such as UV radiation or reactive species. CAPP has been employed in inactivation of viruses, to combat resistant microorganisms (antibiotic resistant bacteria, spores, biofilms, fungi) and tumors, to degrade toxins, to modify surfaces and their properties, to increase microbial production of compounds, and to facilitate wound healing, blood coagulation, and teeth whitening. The mini-review provides a brief overview of non-thermal plasma sources and recent achievements in biological sciences. We have also included pros and cons of CAPP technologies as well as future directions in biosciences and their respective industrial fields.
The term plasma was first used by Irving Langmuir in 1928 and describes quasi-neutral ionized or partially ionized gas in electric discharge. The plasma consists of variety of particles, neutral atoms and molecules, charged particles (electrons and ions), metastable particles (excited atoms and molecules, radicals), and photons (Bellan 2008). Depending on temperature of particles, plasma can be classified into two categories: equilibrium or thermal plasma and non-equilibrium or non-thermal plasma. The thermal plasma is characterized by an almost completely ionized gas and high temperature of at least 15,000 K (Roth 2001). The non-thermal or cold plasma is a partially ionized gas with temperature generally close to room temperature (maximum 340 K). Since the treatment by cold plasma is delivered at room temperature, damaging effects on biological tissues and thermolabile matrices can be minimized while still maintaining disinfection and sterilization efficacy. To date, several types of cold plasma have been developed. Cold atmospheric pressure plasma (CAPP) is frequently used in many life science and agricultural technologies such as medical treatment or plant and food preservations. This review presents recent developments, challenges, and future options of CAPP in biological decontamination and interactions with various tissues and organisms. In the review, CAPP chemistry, energy source generation, equipment design, and conditions are summarized together with application and modes of action in biological systems.
limits and potentials
There are numerous potential benefits to plasma therapy, but it also has significant restrictions (Fig. 2). Plasma that did not generate heat and ran at low pressure needed a substantial upfront expenditure. Costs for making CAPP in ambient air were lower from the get-go, and they stayed that way throughout the lifetime of the product. CAPP is widely praised for its adaptability, speed, low cost, environmental friendliness, and water and energy efficiency. It’s a method of disinfection that doesn’t include any chemicals yet is more adaptable and effective than medications. Therefore, CAPP therapy for antibiotic-resistant bacteria may provide a promising option in the fight against multi-drug resistance.
You can see the benefits and drawbacks of plasma therapy in Figure 2.
picture in its entirety
Although non-thermal plasma is already utilised in a variety of medical treatments, using it in an industrial setting to decontaminate is proving challenging. Determining a plasma dosage that might be used in treatment regimens is one of the main challenges. Based on the plasma source’s design, the composition of the working gas, the structure of the biological target, and the predicted plasma dose, the maximum positive impact is achieved with minimal matrix damage. The effectiveness of the plasma therapy may also be affected by the surface matrix makeup. Since plasma treatment may not work as well on uneven surfaces, this may be more noticeable when trying to remove contaminants from such areas. Bacterial cells that can survive without being exposed to plasma are often concealed by the rough surfaces. Additionally, bacteria may form aggregates, colonies, or biofilms, which serve to shield the bacterium’s hidden cells. The cleaning was only partially successful due to the fact that plasma particles tend to cling closer to the surface and have a limited capacity to penetrate deeper layers of biological material.
It is difficult to list all of the pros and cons since there are so many different designs and use cases to consider. So, there isn’t a universal prototype tool that can be used for everything. APPJ, for example, may find use in the medical and dental fields. It may find use in the treatment of localised contamination, plasma-induced blood coagulation, wound healing, cancer therapy, and an increase in implant biocompatibility, among other areas. In contrast, industries like the food industry need not just the treatment of huge and diverse surfaces, but also a high degree of efficiency. The necessity for a constantly flowing working gas and a slightly confined plasma volume are two challenges that prevent the design and operation of APPJs from reaching their full potential. But DBDs shine when dealing with large surfaces and a wide variety of sample sizes and shapes. Pros include using little to no working gas, producing a high-power-density plasma, and only needing a few seconds of exposure time. Most plasma devices were developed for use in a narrow range of therapies. To put plasma technology to use in factories, plasma source designs must be created that treat a huge volume of material in a single process. The connecting of many discharge units is one approach to reaching industrial (continuous) levels of output.