Fabrication of calcium ion sensitive diamond field effect transistors (FETs) based on immobilized calmodulin

We have developed calcium (Ca2+) ion sensitive solution-gate field effect transistors (SGFETs) on polycrystalline diamond by using partial amination and immobilization of calmodulin (CaM), a specific protein to calcium ions. The CaM is covalently immobilized on functionalized diamond surface, and the functionalized surface was analyzed by X-ray photoelectron spectroscopy, respectively. Also, the high performance of the CaM-immobilized diamond SGFET for detecting Ca2+ were studied with respect to high selectivity and sensitivity in various concentrations and pH.