Application of hydroxyl radicals as a new high-level disinfection method: elucidation of the bactericidal mechanism for spores

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K17057
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 57050:Prosthodontics-related
• Research Institution: Tohoku University
• Principal Investigator: Shishido Shunichi 東北大学, 歯学研究科, 助教 (20850613)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 水酸化ラジカル / 芽胞 / 殺菌 / 高水準消毒

Outline of Final Research Achievements

In this study, the hydrogen peroxide photolysis technique was applied as a safe, novel high-level disinfection method in prosthodontic clinical practice. The bactericidal effects of this technique against bacterial spores were evaluated, and the mechanisms of action were analyzed. The experiments utilized two bacterial species: Bacillus subtilis and Bacillus cereus. Initially, spore cultivation methods were established, and the bacterial spores were observed using phase-contrast microscopy and scanning electron microscopy (SEM). The hydrogen peroxide photolysis technique demonstrated efficient bactericidal effects on Bacillus cereus spores. The bactericidal action was wavelength-dependent and time-dependent. SEM and electron spin resonance (ESR) analyses suggested that the hydrogen peroxide photolysis technique might alter or destroy some structural components of the bacterial spores.

Free Research Field

歯科補綴学

Academic Significance and Societal Importance of the Research Achievements

過酸化水素光分解殺菌法は、これまで一般的な栄養型細菌に対し、短時間で高い殺菌効果を示すことが報告され、主に歯科治療への応用が進められてきた。一方で、歯科治療で用いられる器具の消毒については、滅菌処理ができない材料の場合、高水準消毒が求められる。しかしながら、既存の高水準消毒法では、消毒処理が長時間に及ぶ場合や、作業者への毒性等の問題があった。本研究の成果として、過酸化水素光分解法により細菌芽胞を効率的に殺菌できることが示唆されたことから、本殺菌法は既存の高水準消毒薬と比べて安全な、新規高水準消毒法となりうる。今後は、他の高水準消毒薬との比較や、医療現場への応用へ向けた取り組みを行っていきたい。