Accelerated Mice Skin Acute Wound Healing In Vivo by Combined Treatment of Argon and Helium Plasma Needle

Background and Aims

The efficacy of a direct application of plasma needle to in vivo wound healing was experimentally studied in mice. This kind of plasma has achieved considerable success in blood coagulation and tissue restoration in mice. In the development of the present study, an argon plasma needle was chosen for coagulation purposes, whereas for healing purposes, a helium plasma needle was used.

Methods

Treatment was applied with a plasma needle produced by argon and helium to a wound induced in laboratory mice. Tissue regeneration was carried out by three argon plasma treatments with 0.5 SLPM flow for 1 min and three treatments of helium with 1.5 SLPM flow. Intervals between each treatment were 5 min and 60 min for argon and helium plasmas, respectively, thus completing a total treatment time of 180 min. Histological sections were performed to corroborate the internal bleeding and tissue regeneration.

Results

After three treatments with argon plasma, the blood produced in the wound was coagulated and protein material appeared. By means of treatment with helium plasma, an approach of the wound edges was produced until the conclusion thereof. These results were corroborated histologically.

Conclusions

This type of acceleration during the skin wound healing process can be attributed to the formation of reactive species such as NO, which were increased in the helium plasma needle with respect to the argon plasma needle.

Introduction

In biology and medicine, the term plasma refers to the liquid component of the blood cells, whereas this same word in physics refers to the fourth state of matter, a partially ionized gas with a neutral electrical behavior 1, 2, 3. Recently, the field of plasma physics has been significantly expanding with many applications, in particular, plasma in medicine and as an independent medical field. It is emerging worldwide in a manner comparable to the development several years ago of laser technology (4). Research areas such as plasma surface modification (5), plasma bio-decontamination, and therapeutic plasma are often collectively known as plasma medicine (6). The scientific basis of plasma medicine rests on a fundamental knowledge of the plasma interaction mechanisms with living cells and tissue (7).

Various biomedical applications of nonthermal atmospheric pressure plasma sources have been explored recently. These have been focused on the treatment of medical equipment and even living tissue. A major goal of tissue treatment with plasmas is nondestructive surgery (8). Provided that plasmas allow fast and efficient bacterial inactivation, they seem suitable for the asepsis of surgical tools and local tissue disinfection. However, as it is expected that a novel approach to surgery will emerge from plasma science, a great research effort must be made before these techniques become common in medicine. Examples of plasma applications in medicine are bacterial decontamination of medical instruments (9), coating of implants with biocompatible layers (10), surface modification of substrates for cell culture (6), blood coagulation by argon plasma 6, 11, 12, 13, 14, 15, and dermatology 7, 16, 17, 18, 19.

The most frequently used plasma devices in medical applications are the dielectric barrier discharge (DBD) (8), the floating electrode dielectric barrier discharge (FE-DBD) 6, 12 and the plasma needle (16). The plasma needle device was originally designed for dental applications (20). It produces a small-diameter low-power nonthermal atmospheric pressure glow discharge. A radiofrequency (RF) high-voltage signal is applied to a needle-shaped electrode located inside a concentric gas flow nozzle with a diameter of a few millimeters.

The plasma needle generates a multitude of reactive oxygen species (ROS) together with reactive nitrogen species (RNS) as well as ultraviolet (UV) radiation, and these can reach the surface of the living tissue (6). These reactive species can play a key role in proliferation processes, for instance, involved in collagen production of fibroblasts and synthesis of growth factors 21, 22.

The small size of the plasma needle device allows focusing a specific treatment on spots with a few-millimeter diameter without applying excessive heat to the living tissue. The aim of the present paper is to report the effect of subsequent argon and helium plasma needle treatment at room temperature and atmospheric pressure in regard to the time required for skin wound healing in mice in vivo.