STUDY OF REAGENTLESS PHOSPHATE SENSING SYSTEM

点击翻译按钮获取中文摘要

The purrpose of this study is to establish the pliciple of reagentless phosphate sensor utilizing phosphate binding protein (PBP). First of all PBP was extracted from Eschericia Coli., and purified. Activity of obtained PBP was assayd and it was almost same as the previously reported data.PBP was immobilized on a sheat of nitrocellulose membrane. Potential change of this membrane was observed to phosphate, with use of Ag/AgCl Electrode. The potential change depended on the concentration of phosphate more than 1mM.An atttempt of miniaturization of phosphate sensor was done by immobilizing PBP on an ion sensitive field effect transistor (ISFET). As the result of examination of membrane support materials, immobilization method, and the estimation of immobilization of the protein by FT-IR,PBP was immobilized in a layr of polyvinylbutyral resin entrapment method.Response of the PBP immobilized ISFET to potasium phosphate was observed at the range of sub mM order. However, the sensor responded to potasium ion either. it was supposed that the response should be corrected by subtraction of the response to potasium, to obtain net response to phosphate. Moreover thestability of immobilized PBP was not satisfactory to ascertain its response to various ions.At last PBP was immobilized in PVA-SbQ by entrappment method, and the immoibilized PBP membrane was fixed on a platinum electrode. The membrane potential was measured against Ag/AgCl counter electrode. The higher potential changer to phsophate was observed than to other anions with this system. The potential change of this system to phosphate showed linear relationship to the concatration of phosphate at the range of 10-100mM.From these results, the reagentless phosphate sensing is shown to be possible system.