Logic gates from sodium and potassium ion selective bulk optode

Abstract

The optode membranes incorporating tetramethoxyethylester calix[4]arene or valinomycin for sodium ion or potassium ion recognition, respectively and different types of chromoionophores in a plasticized poly(vinyl chloride), (PVC) matrix was fabricated to operate as chemical logic gates. A competitive ion exchange equilibrium, which was the response mechanism, could relate to a logic system under the action of two chemical inputs (H+ and Na+/K+). The response change, an optical character of optode membranes, was the output signal. The absorbance behaviors of sodium and potassium selective optodes at different protonation and coordination environments were studied extensively. Typical optode systems, i.e. sodium and potassium optodes were found to function as INH A, INH B, NINH A and NINH B gates. Mismatched ionophore-analyte ion optodes (tetramethoxyethylester calix[4]arene-K+) which could partially determine ion contents, also produced INH and NINH gates but not as many conditions as the matched cases. Switching proton input to an opposite logic condition can employ AND/NAND and NOR/OR logic gates from the condition of INH A/NINH A and INH B/NINH B respectively. NOR and OR gates were achieved from the modified mixed-ionophore optode systems (tetramethoxyethylester calix[4]arene and valinomycin) with Na+ and K+ as inputs. As well as processing information, our system could be used for information gathering as a miniaturized diagnostic system capable of working under physiological conditions.