title: High-κ GdTixOy sensing membrane-based electrolyte-insulator-semiconductor with magnetic nanoparticles as enzyme carriers for protein contamination-free glucose biosensing.
abstract: This paper reports an electrolyte-insulator-semiconductor (EIS) device featuring a novel high-κ GdTixOy sensing membrane for high-performance pH sensing and glucose biosensing. The effect of the annealing temperature (700, 800, or 900°C) on the sensing properties of the GdTixOy membranes was investigated. The GdTixOy EIS device annealed at 900°C exhibited the greatest pH sensing performance, including the highest sensitivity (62.12mV/pH), the smallest hysteresis voltage (5mV), and the lowest drift rate (0.4mV/h), presumably because of its well-crystallized GdTixOy structure. To overcome the problems typically encountered during the practical application of biosensors (e.g., protein adsorption; preservation of enzymatic activity), we employed Fe3O4-based magnetic nanoparticles (MNPs) as enzyme carriers. The adsorption of serum protein on the unmodified sensing membrane led to poor EIS-based pH sensing (r(2)=0.71); the performance was greatly improved, however, after attaching the MNPs to the sensing membrane, thereby blocking protein adsorption significantly (by 98%) and allowing excellent pH sensing (r(2)=0.99). Moreover, we prepared a hybrid configuration of the proposed GdTixOy membrane-EIS, with magnetically attached glucose oxidase-immobilized MNPs, for glucose biosensing. The use of MNPs as enzyme carriers effectively preserved the enzymatic activity of glucose oxidase, with 45.3% of the original enzymatic activity retained after 120h of storage at 4°C (compared with complete loss of the free enzyme's activity under the same storage conditions). In addition, the proposed biosensor exhibited superior detection sensitivity of 11.03mV/mM relative to that (8.17mV/mM) obtained using the conventional enzyme immobilization method. Finally, we established the accuracy of the proposed method for blood glucose measurement; gratifyingly, blood glucose detection was comparable with the high-sensitivity glucose quantification obtained using a commercial glucose assay kit.
authors.affiliation: Graduate Institute of Biochemical and Biomedical Engineering, Chang Gung University, Kwei-Shan, Tao-Yuan 33302, Taiwan.
authors.forename: Min-Hsien
authors.initials: MH
authors.lastname: Wu
authors.forename: Hung-Wei
authors.initials: HW
authors.lastname: Yang
authors.forename: Mu-Yi
authors.initials: MY
authors.lastname: Hua
authors.forename: Yen-Bo
authors.initials: YB
authors.lastname: Peng
authors.forename: Tung-Ming
authors.initials: TM
authors.lastname: Pan
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D004573:Electrolytes; D005947:Glucose / Q000302:isolation & purification*; D005949:Glucose Oxidase; D006801:Humans; D006863:Hydrogen-Ion Concentration; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D012666:Semiconductors; D013696:Temperature
chemical_list: D004573:Electrolytes; D058185:Magnetite Nanoparticles; D005949:Glucose Oxidase; D005947:Glucose