Biofilm Degradation by Seashell-Derived Calcium Hydroxide and Hydrogen Peroxide

Abstract

Microbial cells and self-produced extracellular polymeric substances assembled to form biofilms that are difficult to remove from surfaces, causing problems in various fields. Seashell-derived calcium hydroxide, a sustainable inorganic material, has shown high bactericidal activity even for biofilms due to its alkalinity. However, its biofilm removal efficacy is relatively low. Herein, we report a biofilm degradation strategy that includes two environmentally friendly reagents: seashell-derived calcium hydroxide and hydrogen peroxide. A biofilm model of Escherichia coli was prepared in vitro, treated with calcium hydroxide–hydrogen peroxide solutions, and semi-quantified by the crystal violet stain method. The treatment significantly improved biofilm removal efficacy compared with treatments by calcium hydroxide alone and hydrogen peroxide alone. The mechanism was elucidated from calcium hydroxide–hydrogen peroxide solutions, which suggested that perhydroxyl anion and hydroxyl radical generated from hydrogen peroxide, as well as the alkalinity of calcium hydroxide, enhanced biofilm degradation. This study showed that concurrent use of other reagents, such as hydrogen peroxide, is a promising strategy for improving the biofilm degradation activity of seashell-derived calcium hydroxide and will contribute to developing efficient biofilm removal methods.

Comparison of antimicrobial properties of inorganic peroxide polymer composites

“…35 The release of Ca 2+ ions from calcium peroxide has also been reported to elicit an antibacterial effect. 36 The generation of ROS which has been found to improve biofilm degradation appeared to be similar between the CP and ZP, 37 but the antibacterial effectiveness of ZP was lower than CP and MP. Consequently, ROS appeared to be not a key factor rather the combination of pH and hydrogen peroxide.…”

Impact of apigenin and seashell nano-additives on the antifungal and roughness behavior of a soft denture liner

“…The secondary mechanism of antimicrobial activity is by the dissociation of CaO in the slurry phase and generation of the high content of Ca2+ and ROS (Reactive Oxygen Species), a cationic environment that bonds with the cardiolipin (negative surface charge) the main lipid in the cell membrane of the pathogen. The binding of Ca2+ and cardiolipin results in changing the cell metabolism, starvation and cell wall rupture of the fungal cell (29,30).…”

Sequential Approach for Water Purification Using Seashell-Derived Calcium Oxide through Disinfection and Flocculation with Polyphosphate for Chemical Pollutant Removal

“…In this context, seashell-derived CaO, which is prepared via heat treatments of seashells composed mainly of calcium carbonate (CaCO 3 ), has been used as a food additive for pH control, nutrient supplement, dough conditioning, and other purposes. , Moreover, studies have investigated its application as a disinfectant with excellent microbicidal and virucidal activities. , The microbicidal and virucidal activities originate mainly from the alkalinity of calcium hydroxide (Ca(OH) 2 ) produced from CaO via hydration, while reactive oxygen species generated by CaO particles may also contribute. ,, Seashell-derived CaO has been shown to exhibit a broad spectrum of microbicidal and virucidal activities against various pathogenic bacteria, viruses, bacterial spores, , fungi, and biofilms, − and its aqueous solutions and suspensions have been investigated for the disinfection of food, such as vegetables, , meats, , and fish . Moreover, we have recently explored the medical use of these water-based disinfectants from seashell-derived CaO. ,− Given that it is a common food additive, seashell-derived CaO is a promising disinfectant for producing safe and pure water that is usable for drinking and even medical purposes; however, the potential of seashell-derived CaO for use in water treatments has rarely been investigated so far.…”

“… 27 Moreover, we have recently explored the medical use of these water-based disinfectants from seashell-derived CaO. 11 , 28 − 32 Given that it is a common food additive, seashell-derived CaO is a promising disinfectant for producing safe and pure water that is usable for drinking and even medical purposes; however, the potential of seashell-derived CaO for use in water treatments has rarely been investigated so far.…”