First evidence of singlet oxygen species mechanism in silicate clay for antimicrobial behavior

•The physical trapping mechanism is proposed for the NSP interaction with bacteria.•The NSP generates singlet oxygen species under UV irradiation using EPR detection.•We first time report the ROS generation of clay interacting with bacteria.

Nanoscale silicate platelets (NSPs) from the natural silicate clay minerals were shown to have antimicrobial ability through physical trapping mechanism. The NSP could inhibit the growth of drug-resistant species such as methicillin-resistant Staphylococcus aureus and silver ion-resistant Escherichia coli. We further found that the NSP generated singlet oxygen species under ultraviolet irradiation. This is the first time to report the ability of generating singlet oxygen species by the platelets of ca. 80 × 80 × 1 nm in geometric shape. The ability to emit singlet oxygen species of the NSP clay provides an explanation for “physical trapping” antimicrobial mechanism.

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