Polymeric mercaptosilane-modified platinum electrodes for elimination of interferants in glucose biosensors.
An oxidase-based glucose sensor has been developed that uses a mercaptosilane-modified platinum electrode to achieve selectivity of electrochemical interferants. A platinum-iridium (9:1) wire (0.178 mm o.d., sensing area of 1.12 mm2) is modified with (3-mercaptopropyl)trimethoxysilane. The modified sensors show excellent operational stability for more than 5 days. Glucose oxidase is immobilized on the modified surface (i) by using 3-maleimidopropionic acid as a linker or (ii) by cross-liking with bovine serum albumin using glutaraldehyde. Sensitivities in the range of 9.97 nA/mM glucose are observed when the enzyme is immobilized by method ii. Lower sensitivities (1.13 x 10(-1) nA/mM glucose) are observed when immobilization method i is employed. In terms of linear response range, the sensor enzyme-immobilized by method i is superior to that immobilized by method ii. The linearity is improved upon coating the enzyme layer with polyurethane. The sensor immobilized by method ii and coated with polyurethane exhibits a linear range to 15 mM glucose and excellent selectivity to glucose (0.47 nA/mM) against interferants such as ascorbic acid, uric acid, and acetaminophen.
Jung
S K
SK
Department of Chemistry, University of Kansas, Lawrence 66045, USA.
Wilson
G S
GS
D015374:Biosensing Techniques; D004566:Electrodes; D004800:Enzymes, Immobilized; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase; D017646:Organosilicon Compounds; D010984:Platinum / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*
D004800:Enzymes, Immobilized; D017646:Organosilicon Compounds; D012821:Silanes; D010984:Platinum; C102833:(3-mercaptopropyl)trimethoxysilane; D005949:Glucose Oxidase; D005947:Glucose