Enzymatically functionalized polyaniline thin films produced with one-step electrochemical immobilization and its application in glucose and urea potentiometric biosensors

Author(s)

Pedroza Dias Mello, Hugo Jose Nogueira ^[1] ; Mulato, Marcelo ^[1]

Affiliation

^[1] Univ Sao Palo, Dept Phys, Fac Philosophy Sci & Letters Ribeirao Preto, Av Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil

• Document type: Journal article
• Source: BIOMEDICAL MICRODEVICES; v. 22, n. 1 FEB 27 2020.
• Web of Science Citations: 1

Abstract

Glucose and urea enzymatic biosensors were fabricated. One-step electrochemical immobilization process was used to produce thin polyaniline films with entrapped enzymes. Chronopotentiometric analysis, scanning electron microscopy, electrochemical impedance spectroscopy and optical reflectance spectroscopy were used to determine the structure-property relationship of the functionalized polymeric thin films. The device has a recognition stage connected to a potentiometric field-effect-transistor stage and is based on the measurement of microenvironment pH variation or locally produced ions. Optimization of biosensor fabrication and effective measurement conditions were performed. The optimized films presented sensitivity, linearity and detection range to glucose of 14.6 +/- 0.4 mV/decade, 99.8% and from 10(-4) M to 10(-1) mol/L. Two different biosensors were produced based on the enzymatic reaction of urea with selectivity to ammonium or hydroxyl ions. For ammonium ion selective film, the sensor's parameters were 14.7 +/- 0.9 mV/decade, 98.2% and from 10(-5) to 10(-1) mol/L. For the hydroxyl ion selective film, the same parameters were 7.4 +/- 0.5 mV/decade, 98.1% and from 10(-5) to 10(-1) mol/L. The change in the oxidation state of the polymeric matrix explains: i) the large loss of functionality of glucose biosensor in time, ii) the conservation of functionality to the hydroxyl ions for urea biosensor and iii) the selectivity variation of the ammonium ion selective urea biosensor. The results indicate that the polymeric matrix has indeed changeable selectivity, what can be applied in different situations for biosensors production. (AU)

• FAPESP's process: 14/09562-4 - Microelectronic biossensors associated with electrochemical techniques
• Grantee: Marcelo Mulato
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/24559-0 - Multimodal array of enzymatic biosensors: potentiometric differential mode, optical and conductometric.
• Grantee: Hugo José Nogueira Pedroza Dias Mello
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/24201-6 - Microelectronic Platforms for Electrochemical, Piezoelectric and FETs Biosensors
• Grantee: Marcelo Mulato
• Support Opportunities: Regular Research Grants