Glucose Biosensor Based on Nanocomposite Films of CdTe Quantum Dots and Glucose Oxidase

Abstract

A blood glucose sensor has been developed based on the multilayer films of CdTe semiconductor quantum dots (QDs) and glucose oxidase (GOD) by using the layer-by-layer assembly technique. When the composite films were contacted with glucose solution, the photoluminescence of QDs in the films was quickly quenched because the enzyme-catalyzed reaction product (H2O2) of GOD and glucose gave rise to the formation of surface defects on QDs. The quenching rate was a function of the concentration of glucose. The linear range and sensitivity for glucose determination could be adjusted by controlling the layers of QDs and GOD. The biosensor was used to successfully determine the concentration of blood glucose in real serum samples without sample pretreatment and exhibited satisfactory reproducibility and accuracy.

Fabrication of Bienzymatic Glucose Biosensor Based on Novel Gold Nanoparticles‐Bacteria Cellulose Nanofibers Nanocomposite

“…In the similar way, HRP and GOx were proved to be successfully immobilized at PDDA/HRP/Au-BC/GCE and PDDA/ GOx/Au-BC/GCE. The R et of PDDA/GOx-HRP/Au-BC/ GCE was much smaller than that of PDDA/GOx-HRP/ GCE (1027 W), indicating Au-BC nanocomposite had good conductivity and could make the electron transfer of [Fe(CN) 6 ] 3À/4À easily.…”

“…Figure 2 exhibited the Nyquist plot of EIS at the bare and the modified GCEs, which were obtained in 4.0 mM [Fe(CN) 6 ] 3À/4À solution with the frequencies from 100 kHz to 0.1 Hz. Significant differences in the impedance spectra were observed.…”

Enzyme‐Based Biosensors: Synthesis and Applications

“…Although numerous established strategies have been successfully employed to construct new nanocomposite biosensors, several limitations, such as time and cost, diffi culty of large -scale production, and absence of universality, inevitably hinder the practical applications of such methods [15,43] . Since Decher [118] pioneeringly introduced an alternative way to develop a new generation of nanocomposite biosensor based on the alternative deposition of oppositely charged species on the substrates by using the electrostatic layer -by -layer self -assembly technique, membranes designed layer -bylayer are expected to contribute in that sense due to their simplicity, economy, universality, and environmentally friendly properties [15,119,120] . In most cases, membranes are in the form of permselective planar fi lms (organosilane, polyurethane, cellulose acetate, etc.)…”

“…Faure et al [43] also reported generating amperometric biosensors by a new enzyme immobilization process and investigated the analytical properties of polypyrrole biosensors made with free or encapsulated GOx. Recently, Tang et al [15] fabricated a blood glucose sensor based on multilayer fi lms of CdTe semiconductor quantum dot s ( QD s) and GOx by using the layer -by -layer assembly technique, as shown in Figure 5.3 .…”

“…Among them, biosensor materials have been a fast -growing research fi eld over the past several decades due to their potential application in a various analytical tasks, such as medical diagnostics, food industry, water quality control, health safety, environmental monitoring, pharmaceutics, and bioassays [3 -7] . As a result, various kinds of biosensor materials, including carbon nanotube s ( CNT s) [8,9] , titanate nanotube ( TNT ) [10,11] , inorganic particles [4,12] , nanoporous spheres [13,14] , and polymer membranes [15,16] , have been prepared as enzyme carriers by using established strategies for enzyme immobilization.…”