Applications of Sol−Gel-Derived Membranes to Neutral Carrier-Type Ion-Sensitive Field-Effect Transistors

Abstract

Sol-gel-derived membranes encapsulating neutral carriers, such as valinomycin and a bis(crown ether) derivative, were fabricated as novel ion-sensing membranes for neutral carrier-type ion-sensitive field-effect transistors (ISFETs). The neutral carrier-type sol-gel-derived membranes obtained with an initial diethoxydimethylsilane/tetraethoxysilane ratio of 3 gave excellent results for membrane processibility and sensitivity, response time, and selectivity in the resulting ion sensors. The sol-gel-derived ion-sensing membranes containing neutral carriers are superior in the thrombogenic property to their corresponding plasticized poly(vinyl chloride) membranes. The potassium and sodium ISFETs thus obtained were successfully applied to the ion assay in blood sera.