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Generating Nanoparticle Mists from Solutions with Plasma for Medical Use

Researchers have found a safe way to generate a mist of nano-sized particles using plasma, which has the potential to be utilised in novel methods for transdermal drug delivery.

In recent years, the field of plasma medicine has been attracting interest as a novel therapy in medicine. It centres around atmospheric pressure plasma – one of the four fundamental states of matter, comprising charged, free-moving particles – and its direct effects, which include heat, and chemically reactive species which may be applied to targeted areas of the body. However, the limitations of current technologies only allow for the use of plasma to treat lesions and wounds externally, and more fine-tuning to pre-existing technologies has to be done before they may be used in internal medicine.

Fortunately, a team of researchers from the Tokyo University of Agriculture and Technology has found a way to create a nano-sized mist using plasma, which may have potential uses in internal medicine. Their findings were published in Scientific Reports on June 22.

Plasma is currently used to address burns and wounds and may also be used as a precise tool to remove benign skin lesions. Other technologies involving plasma include transdermal drug delivery systems where the skin is exposed to plasma. If the concept is to be further extended beyond transdermal drug delivery and into drug delivery to other internal organs, a nano-sized approach is required.

If the nanoparticles could be generated directly from a solution of the drug instead, targeted drug delivery within the body would be made much easier. This might be made possible using plasma, as nano-sized particles generated by it allow drugs to cross the skin and other tissue barriers with greater ease and reach the target area intact.

Thus, the researchers developed a biologically safe way to use plasma to create the nano-sized mist from various types of solutions. By passing the solutions through a dielectric barrier discharge, mists from polar and non-polar solvents were obtained. The electrical conductivity of the solution was observed to be a key factor in affecting the rate at which the mist was generated. 

The method they developed to create the mist makes use of two charged electrodes that sandwich a dielectric (also known as an insulator), which is more commonly used in the manufacturing industry. This method is safer and more convenient than the alternative electrostatic spray method to generate nanoparticle mists as it does not require high voltages and grounding of the target, reducing the likelihood of a potentially fatal electric shock.

The increased safety of the method to generate nanoparticle mists allows for the potential expansion of their use in biological systems. “We have succeeded in developing a technology to generate nano-sized mist by passing liquid through a dielectric barrier discharge at low velocity. This technology is safer than the conventional electrostatic spray, which is used in the industrial field,” said Daisuke Yoshino, associate professor at the Tokyo University of Agriculture and Technology. “Ultimately, we aim to apply our technology to biomedical fields, such as transdermal drug delivery systems.” [APBN]

Source: Watanabe et al. (2022). Potential generation of nano-sized mist by passing a solution through dielectric barrier discharge. Scientific Reports, 12(1), 1-10.