The Quality Optimization of SiO₂/Graphene Material as Sensing Layer for <i>Escherichia coli</i> Bacteria Sensor Application

Abstract

Escherichia coli bacteria sensors have been broadly developed broadly to overcome a diarrheal disease caused by Escherichia coli on poor hygienic water. Sensing layer, as a main part of the sensor, contacts directly to the analyte on sensors system. Some materials were costly and harmful to detect bacteria. Potentially, graphene is a natural carbon derivative with some excellence properties; easy synthesis, and biocompatible. Hence, the quality of the SiO2/graphene sensing layer was conducted through optical, physical, and electrical characterization to analyze biocompatibility, repeatability, and selectivity. The result showed that Escherichia coli bacterial growth was found around SiO2/graphene after bacterial exposure indicating a biocompatible material. Raman peak also pointed the fingerprint of graphene after 25 times Escherichia coli exposure through G (1584.52 cm–1) and 2D peak (2701.5 cm–1) promising as a repeatable material. The ID/IG ratio increased by the time the bacteria exposure times increased indicating a withstand material from defects and or disorders after bacteria exposure. Through I/V meter, the increasing number of Escherichia coli could increase the resistance value of SiO2/graphene. This sensing layer could detect the presence of Escherichia coli in limit of detection 16 CFU/mL.