Penicillin g biosensor, systems comprising the same, and measurement using the systems

Abstract

A penicillin G biosensor, systems comprising the same, and measurement using the systems. The penicillin G biosensor has an extended gate field effect transistor (EGFET) structure and comprises a metal oxide semiconductor field effect transistor (MOSFET) on a semiconductor substrate, a sensing unit comprising a substrate, a tin oxide film on the substrate, and a penicillin G acylase film immobilized on the tin oxide film, and a conductive wire connecting the MOSFET and the sensing unit.

1 . A system of measuring pH value of a solution, comprising:
 an extended gate field effect transistor;   a reference electrode supplying a stable voltage;   a semiconductor characteristic instrument connecting the extended gate field effect transistor and the reference electrode, respectively;   a temperature controller comprising a temperature control center, a thermocouple, and a heater, wherein the temperature control center connects the thermocouple and the heater, respectively; and   a light-isolation container isolating the sensing unit from photosensitive effect, wherein Measurement of pH value of a solution comprises pouring a solution into the light-isolation container, immersing the extended gate field effect transistor, the reference electrode, and the thermocouple in the solution, adjusting temperatures of the solution by the heater controlled by the temperature control center after detecting temperature variations of the solution by the thermocouple, transmitting measured data of the extended gate field effect transistor and the reference electrode to the semiconductor characteristic instrument, and reading out current-voltage (I-V) values of the sensing unit by the semiconductor characteristic instrument to obtain a concentration of penicillin G in the solution.   
   
   
       2 . The system as claimed in  claim 1 , wherein the semiconductor characteristic instrument is Keithley  236 . 
   
   
       3 . The system as claimed in  claim 1 , wherein the solution has a temperature of 25° C. controlled by the temperature controller. 
   
   
       4 . The system as claimed in  claim 1 , wherein the reference electrode is an Ag/AgCl reference electrode. 
   
   
       5 . The system as claimed in  claim 1 , wherein the light-isolation container is a dark box. 
   
   
       6 . A method of measuring a sensitivity of an extended gate field effect transistor, using a system of measuring pH value of a solution, the system comprising:
 an extended gate field effect transistor;   a reference electrode supplying a stable voltage;   a semiconductor characteristic instrument connecting the extended gate field effect transistor and the reference electrode, respectively;   a temperature controller comprising a temperature control center, a thermocouple, and a heater, wherein the temperature control center connects the thermocouple and the heater, respectively; and   a light-isolation container isolating the sensing unit from photosensitive effect, wherein Measurement of pH value of a solution comprises pouring a solution into the light-isolation container, immersing the extended gate field effect transistor, the reference electrode, and the thermocouple in the solution, adjusting temperatures of the solution by the heater controlled by the temperature control center after detecting temperature variations of the solution by the thermocouple, transmitting measured data of the extended gate field effect transistor and the reference electrode to the semiconductor characteristic instrument, and reading out current-voltage (I-V) values of the sensing unit by the semiconductor characteristic instrument to obtain a concentration of penicillin G in the solution,   wherein the method comprises:   (a) immersing an extended gate field effect transistor in an acidic or basic solution;   (b) recording a curve of source/drain current versus gate voltage of the extended gate field effect transistor by the semiconductor characteristic instrument after altering pH values of the acidic or basic solution at a fixed temperature; and   (c) examining the curve to obtain a sensitivity of the extended gate field effect transistor at the fixed temperature and a fixed current.   
   
   
       7 . The method as claimed in  claim 6 , further comprising, measuring the sensitivity of the extended gate field effect transistor with different phosphate buffer solutions. 
   
   
       8 . The method as claimed in  claim 6 , wherein the acidic or basic solution has pH value from 2 to 8. 
   
   
       9 . The method as claimed in  claim 6 , wherein the semiconductor characteristic instrument supplies a voltage from 1 to 6(V) to a gate of the metal oxide semiconductor field effect transistor of the extended gate field effect transistor. 
   
   
       10 . The method as claimed in  claim 6 , wherein the semiconductor characteristic instrument supplies a fixed voltage of 0.2(V) to a source/drain of the metal oxide semiconductor field effect transistor of the extended gate field effect transistor. 
   
   
       11 . The method as claimed in  claim 6 , wherein the acidic or basic solution has a temperature of 25° C. controlled by the temperature controller. 
   
   
       12 . The method as claimed in  claim 6 , wherein the reference electrode is an Ag/AgCl reference electrode.