Breakthrough in Next-Generation Oral Ulcer Management: Integration of Cold Plasma and Nanogel Pharmaceutical Systems

Background

Oral ulcers are one of the most common mucosal diseases, significantly affecting patients’ quality of life. According to epidemiological data, approximately 27.9% of adults suffer from oral ulcers. While these lesions often heal spontaneously within one to two weeks for the general population, patients with conditions such as diabetes, cancer, viral infections, and autoimmune diseases may experience chronic, recurrent oral ulcers that may lead to more severe systemic health issues such as malnutrition and dehydration. Moreover, 65% of patients undergoing treatment for head and neck cancers develop severe oral mucositis, characterized by painful ulcers and difficulty eating, leading to a marked decline in their quality of life.

Current treatments for oral ulcers—such as oral films, sprays, powders, and pastes—face significant limitations, including short therapeutic duration, poor adhesion, and insufficient penetration. The moist and dynamic oral environment limits the retention of medication at the ulcer site, leading to rapid clearance and reduced efficacy. Furthermore, no treatment currently offers a complete resolution of oral ulcers, highlighting the urgent need for a safe, effective, and long-lasting therapy to promote rapid healing.

To address these challenges, this study explores an innovative combination therapy using Cold Atmospheric Plasma (CAP) in conjunction with a nanogel-based pharmaceutical system. CAP, an emerging technology in plasma medicine, has gained attention due to its excellent biocompatibility and therapeutic potential. CAP generates reactive oxygen and nitrogen species (RONS) that modify biological tissue surfaces, enhancing drug permeability and adhesion. Additionally, the nanogel system (GCN) incorporates glucose oxidase (GOx) and catalase (CAT), creating a sustainable oxygen-generating platform that stabilizes the wound microenvironment and may significantly enhance ulcer healing.

Overview of the Study

The study, led by Yanfen Zheng and more than twenty co-authors, involves researchers from prominent institutions such as Xiamen Medical College, Xiamen University, Harbin Medical University, Peking University, and Queensland University of Technology in Australia. It was published in the prestigious journal Advanced Healthcare Materials in its 2025 issue.

Detailed Research Process

1. Development and Characterization of Cold Plasma Device

The research team developed a portable handheld 3D multi-microhole Cold Plasma (CAP) jet device designed for safe and effective application in the oral cavity. The device uses helium gas as the feedstock to generate a stable plasma stream, and its performance was validated using Optical Emission Spectroscopy (OES). The results confirmed the production of various reactive species, including hydroxyl radicals (·OH), reactive nitrogen (N2+), and ozone (O3). These species were demonstrated to form in physiological saline, indicating compatibility with bodily fluids. Safety assessments using porcine skin and primary human gingival fibroblasts (HGF) showed no significant rise in tissue temperature (maintained between 30–33°C) and no observable damage to tissues.

2. Enhanced Drug Absorption Mechanism with CAP Pretreatment

Using Scanning Electron Microscopy (SEM), researchers observed that CAP treatment created micropores on the cell surface without disrupting cellular structure, facilitating the uptake of nanogel (GCN) drugs. Transmission Electron Microscopy (TEM) further showed that CAP significantly increased the internalization of GCN nanoparticles in cells. Fluorescent staining confirmed that CAP enhanced cell membrane permeability by modulating phospholipid bilayers, boosting nanogel uptake efficiency in targeted tissues.

3. Optimization of Nanogels and Synergistic Effects with CAP

GCN nanogels, which encapsulate glucose oxidase (GOx) and catalase (CAT), were synthesized using advanced chemical cross-linking techniques, ensuring sustained oxygen generation. The study integrated nanogels with CAP treatment across cellular and animal models. CAP modified the nanogel structure to exhibit increased micropores and wrinkle-like protrusions, improving nanoparticle dispersion and reducing aggregation. Particle size analysis indicated reduced aggregation post-CAP treatment, enhancing tissue absorption and bioavailability of the nanoparticles.

4. Therapeutic Efficacy in Animal Models

The efficacy of CAP combined with GCN was tested in a Sprague-Dawley rat oral ulcer model. The study divided rats into four groups: control, untreated, watermelon frost (WF), and CAP-treated groups (with or without GCN). Over ten days, the CAP and CAP+GCN groups showed superior results in reducing ulcer size, accelerating healing, and minimizing inflammation compared to the untreated and WF-treated groups. Hematoxylin and Eosin (H&E) staining and Enzyme-Linked Immunosorbent Assay (ELISA) demonstrated that the combined treatment group exhibited faster re-epithelialization and better immune regulation, with prominent activation of CD16+ macrophages and Epidermal Growth Factor Receptor (EGFR).

5. Mechanistic Insights and Immune Microenvironment Analysis

Multicolor Immunofluorescence (IF) staining revealed key immune cell infiltration patterns with CAP and GCN treatment. CAP significantly reduced the infiltration of CD15+ neutrophils while increasing the presence of CD16+ macrophages and EGFR+ cells. Additionally, colocalization of CD16 and EGFR was observed, indicating mechanisms that regulate inflammation and stimulate fibroblast activity to promote tissue repair.

Key Findings and Significance

This study demonstrates the exceptional therapeutic potential of CAP combined with nanogel therapy and presents a groundbreaking approach to overcoming the limitations of conventional oral ulcer treatments. Key findings include:

• Superior Efficacy: CAP+GCN treatment significantly outperformed watermelon frost in a rat oral ulcer model.
• Innovative Mechanisms: CAP mediates reactive species generation, cell membrane permeability, and immune regulation to augment therapeutic outcomes.
• High Safety Profile: Both CAP and GCN were biocompatible with human gingival fibroblasts, showing no cytotoxic effects.
• Clinical Potential: The portable and cost-effective CAP device design positions it for future clinical applications.

Outlook

This study provides a novel direction for treating oral ulcers and other localized mucosal diseases. Future research should include clinical trials to validate these findings in humans and explore its application in chronic wounds, diabetic ulcers, etc., offering precise and efficient solutions for patients. Furthermore, the molecular mechanism underlying CD16 and EGFR colocalization requires broader investigation, contributing to the fields of immune regulation and tissue regeneration. Finally, this pioneering research highlights the vast potential of cold plasma technology in biomedicine, advancing the field of plasma medicine.