Yohei Nakamura: Department of Health Promotion, Division of Infections and Molecular Biology, Kyushu Dental University, Kitakyushu 803-8580, Fukuoka, Japan.
Kaede Okita: Department of Health Promotion, Division of Infections and Molecular Biology, Kyushu Dental University, Kitakyushu 803-8580, Fukuoka, Japan.
Daisuke Kudo: Kyowa Chemical Industry Co., Ltd., Hayashida-cho, Sakaide 762-0012, Kagawa, Japan.
Dao Nguyen Duy Phuong: Kyowa Chemical Industry Co., Ltd., Hayashida-cho, Sakaide 762-0012, Kagawa, Japan.
Yoshihito Iwamoto: Kyowa Chemical Industry Co., Ltd., Hayashida-cho, Sakaide 762-0012, Kagawa, Japan.
Yoshie Yoshioka: Department of Health Promotion, Division of Infections and Molecular Biology, Kyushu Dental University, Kitakyushu 803-8580, Fukuoka, Japan.
Wataru Ariyoshi: Department of Health Promotion, Division of Infections and Molecular Biology, Kyushu Dental University, Kitakyushu 803-8580, Fukuoka, Japan. ORCID
Ryota Yamasaki: Department of Health Promotion, Division of Infections and Molecular Biology, Kyushu Dental University, Kitakyushu 803-8580, Fukuoka, Japan. ORCID
Magnesium hydroxide nanoparticles are widely used in medicinal and hygiene products because of their low toxicity, environment-friendliness, and low cost. Here, we studied the effects of three different sizes of magnesium hydroxide nanoparticles on antibacterial activity: NM80, NM300, and NM700. NM80 (D = 75.2 nm) showed a higher bactericidal effect against than larger nanoparticles (D = 328 nm (NM300) or 726 nm (NM700)). Moreover, NM80 showed a high bactericidal effect against not only exponential cells but also persister cells, which are difficult to eliminate owing to their high tolerance to antibiotics. NM80 eliminated strains in which magnesium-transport genes were knocked out and exhibited a bactericidal effect similar to that observed in the wild-type strain. The bactericidal action involved physical cell damage, as confirmed using scanning electron microscopy, which showed that cells treated with NM80 were directly injured.
