Evaluation of a Microbial Sensor as a Tool for Antimicrobial Activity Test of Cosmetic Preservatives

Abstract

For high-throughput screening of novel cosmetic preservatives, a rapid and simple assay to evaluate the antimicrobial activities should be developed because the conventional agar dilution method is time-consuming and labor-intensive. To address this issue, we evaluated a microbial sensor as a tool for rapid antimicrobial activity testing. The sensor consists of an oxygen electrode and a filter membrane that holds the test microorganisms, Staphylococcus aureus and Candida albicans. The antimicrobial activity of the tested cosmetic preservative was evaluated by measuring the current increases corresponding to the decreases in oxygen consumption in the microbial respiration. The current increases detected by the sensor showed positive correlation to the concentrations of two commercially used preservatives, chlorphenesin and 2-phenoxyethanol. The same tendency was also observed when a model cosmetic product was used as a preservative solvent, indicating the feasibility in practical use. Furthermore, the microbial sensor and microfluidic flow-cell was assembled to achieve sequential measurements. The sensor system presented in this study could be useful in large-scale screening experiments.

Microbial sensor for drug susceptibility testing ofMycobacterium tuberculosis

“…This sensor can immediately respond to minute changes in oxygen caused by external stimuli applied to the immobilized microbial cells. This method is simple and fast and has already demonstrated its advantages in many other applications, such as the measurement of biochemical oxygen demand (Karube et al 1977;Zhang et al 1986;G orsk et al 2012), toxic substances and environmental pollutants (Bachmann et al 1998;Zeljka et al 2002), glucose and its disaccharides (Svitel et al 1998), and antimicrobial activity of cosmetic preservatives (Gomyo et al 2015).…”