Antifungal activity of polymethyl methacrylate/Si3N4 composites against Candida albicans

Giuseppe Pezzotti; Tenma Asai; Tetsuya Adachi; Eriko Ohgitani; Toshiro Yamamoto; Narisato Kanamura; Francesco Boschetto; Wenliang Zhu; Matteo Zanocco; Elia Marin; B Sonny Bal; Bryan J McEntire; Koichi Makimura; Osam Mazda; Ichiro Nishimura

doi:10.1016/j.actbio.2021.03.023

Antifungal activity of polymethyl methacrylate/Si₃N₄ composites against Candida albicans

Acta Biomater. 2021 May:126:259-276. doi: 10.1016/j.actbio.2021.03.023. Epub 2021 Mar 13.

Authors

Affiliations

¹ Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan; Department of Orthopedic Surgery, Tokyo Medical University, 6-7-1 Nishi-Shinjuku, Shinjuku-ku, 160-0023 Tokyo, Japan; The Center for Advanced Medical Engineering and Informatics, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0854, Japan; Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, 465 Kajii-cho, Kyoto 602-8566, Japan; Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan; Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan. Electronic address: pezzotti@kit.ac.jp.
² Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan.
³ Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan.
⁴ Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, 465 Kajii-cho, Kyoto 602-8566, Japan.
⁵ Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan; Department of Immunology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, 465 Kajii-cho, Kyoto 602-8566, Japan.
⁶ Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto 606-8585, Japan; Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602-8566, Japan.
⁷ SINTX Technologies Corporation, 1885 West 2100 South, Salt Lake City, UT 84119, USA.
⁸ Medical Mycology, Graduate School of Medicine, Teikyo University, Itabashi-ku, 173-8605 Tokyo, Japan.
⁹ Division of Oral Biology and Medicine, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA 90095, USA; Division of Advanced Prosthodontics, The Jane and Jerry Weintraub Center for Reconstructive Biotechnology, UCLA School of Dentistry, Los Angeles, CA 90095, USA.

PMID: 33727194
DOI: 10.1016/j.actbio.2021.03.023

Abstract

Previous studies using gram-positive and -negative bacteria demonstrated that hydrolysis of silicon nitride (Si₃N₄) in aqueous suspensions elutes nitrogen and produces gaseous ammonia while buffering pH. According to immunochemistry assays, fluorescence imaging, and in situ Raman spectroscopy, we demonstrate here that the antipathogenic surface chemistry of Si₃N₄ can be extended to polymethylmethacrylate (PMMA) by compounding it with a minor fraction (~8 vol.%) of Si₃N₄ particles without any tangible loss in bulk properties. The hydrolytic products, which were eluted from partly exposed Si₃N₄ particles at the composite surface, exhibited fungicidal action against Candida albicans. Using a specific nitrative stress sensing dye and highly resolved fluorescence micrographs, we observed in situ congestion of peroxynitrite (ONOO^-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si₃N₄ composite, while these radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. These in situ observations suggest that the surface chemistry of Si₃N₄ mimics the antifungal activity of macrophages, which concurrently produce NO radicals and superoxide anions (O₂•^-) resulting in the formation of candidacidal ONOO^-. The fungicidal properties of PMMA/Si₃N₄ composites could be used in dental appliances to inhibit the uncontrolled growth of Candida albicans and ensuing candidiasis while being synergic with chemoprophylaxis. STATEMENT OF SIGNIFICANCE: In a follow-up of previous studies of gram-positive and gram-negative bacteria, we demonstrate here that the antipathogenic surface chemistry of Si₃N₄ could be extended to polymethylmethacrylate (PMMA) containing a minor fraction (~8 vol.%) of Si₃N₄ particles without tangible loss in bulk properties. Hydrolytic products eluted from Si₃N₄ particles at the composite surface exhibited fungicidal action against Candida albicans. Highly resolved fluorescence microscopy revealed congestion of peroxynitrite (ONOO^-) radicals in the mitochondria of the Candida cells exposed to the PMMA/Si₃N₄ composite, while radicals were absent in the mitochondria of identical cells exposed to monolithic PMMA. The fungicidal properties of PMMA/Si₃N₄ composites could be used in dental appliances to inhibit uncontrolled growth of Candida albicans and ensuing candidiasis in synergy with chemoprophylaxis.

Keywords: Candida albicans; Candidacidal activity; Dental prostheses; Fungal sterol; PMMA/Si3N4 composites; Raman spectroscopy; Reactive nitrogen species.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents
Antifungal Agents* / pharmacology
Candida albicans*
Gram-Negative Bacteria
Gram-Positive Bacteria
Polymethyl Methacrylate

Substances

Anti-Bacterial Agents
Antifungal Agents
Polymethyl Methacrylate