Designing a UV-C Powered Self-Disinfecting Makeup Applicator

Makeup is an important part of many women’s lives. However, the applicators used to apply these products harvest a lot of bacteria, causing skin infections, acne, and other harmful effects. Washing these applicators is essential, however, data has shown that many users fail to do so. UV-C disinfection systems have become increasingly popular for their fast, effective nature. The purpose of this study was to expand on these systems by placing one inside a UV-C transparent silicone makeup applicator to ensure more complete, frequent disinfection. It was hypothesized that when this applicator was used, bacteria levels on the applicator would decrease by at least two log reductions because UV-C has been shown to decrease bacteria over four log reductions, and the silicone used has UV-C transparency levels between 90-95%. To test this, a prototype was created by soldering a 16-chip UV-C LED to a set of wires and pulling them through the barrel of the applicator. They were soldered to a power cord and the UV-transparent silicone tip was glued to the top. 60 total trials were performed: 30 trials were tested by infecting the applicator tip with Escherichia coli, and 30 trials were tested by disinfecting the tip with UV-C. The results showed an 85.6% reduction in bacteria. A one-way ANOVA test revealed a statistically significant reduction in mean CFUs between the two groups (F(1, 58) = 27.36, p= <0.001). However, the applicator did not reach 99% reduction, meaning the alternate hypothesis was only partially supported.