Convenience biosensing approach of lactic acid in stratum corneum for skin care assessment.

Background Lactic acid in the stratum corneum contributes to skin flexibility, making it a useful indicator of skin conditions. It is this useful to devise a simple technique to measure the lactic acid in the stratum corneum. To this aim, a printed chip biosensor was developed to analyze lactic acid in tape stripped (TS) stratum corneum samples. Materials and Methods Lactic acid was extracted from TS stratum corneum samples. A normal lactic acid sensor was prepared by applying lactate oxidase (LOD) to a printed chip. Another lactic acid sensor was prepared using LOD and a mediator osmium polymer immobilized on a printed chip. The amount of lactic acid in the extracted solutions was quantified using either the prepared biosensors or an existing analysis method. Results The results measured using the normal lactic acid sensor show low correlation with the results measured using an existing analytical method as a comparison, but those of the mediator osmium lactic acid sensor show high correlation. Conclusions The amount of lactic acid in samples extracted from the stratum corneum using a simple TS technique can be simply analyzed with high accuracy using a printed chip biosensor.