Quantitative Spermidine Detection in Cosmetics using an Organic Transistor‐based Chemical Sensor

Abstract Spermidine is an essential biomarker related to antiaging. Although the detection of spermidine levels is in high demand in life science fields, easy‐to‐use analytical tools without sample purification have not yet been fully established. Herein, we propose an organic field‐effect transistor‐based chemical sensor for quantifying the spermidine concentration in commercial cosmetics. An extended‐gate structure was employed for organic field‐effect transistor (OFET)‐based chemical sensing in aqueous media. A coordination‐bond‐based sensing system was introduced into the OFET device to visualize the spermidine detection information through changes in the transistor characteristics. The extended‐gate‐type OFET has shown quantitative responses to spermidine, which indicates sufficient detectability ( i. e ., the limit of detection for spermidine: 2.3 μM) considering actual concentrations in cosmetics. The applicability of the OFET‐based chemical sensor for cosmetic analysis was validated by instrumental analysis using high‐performance liquid chromatography. The estimated recovery rates for spermidine in cosmetic ingredient products (108–111 %) suggest the feasibility of cosmetic analysis based on the OFET‐based chemical sensor.