title: A droplet-based microfluidic electrochemical sensor using platinum-black microelectrode and its application in high sensitive glucose sensing.
abstract: We describe a droplet-based microfluidic electrochemical sensor using platinum-black (Pt-black) microelectrode. Pt-black microelectrode was generated by electrodeposition of Pt nanoparticles on bare Pt microelectrode. Scanning electron microscope (SEM) image displays a flower-like microstructure of Pt nanoparticels. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) indicate that the Pt-black efficiently decreased the charge transfer resistance and improved the electrocatalytic activity towards oxidation of hydrogen peroxide (H2O2). Compared with bare Pt microelectrode, the current response on Pt-black microelectrode increased 10.2 folds. The effect of applied potential and electrodeposition time has been investigated in detail. The proposed sensor was validated by performing enzyme activity assay in flowing droplets. For demonstration, glucose oxidase (GOx) is chosen as the model enzyme, which catalyzes the oxidation of β-D-glucose to the product H2O2. The enzyme activity of GOx was evaluated by measuring the electrochemical current responding to various glucose concentrations. And the results indicate that this microfluidic sensor holds great potential in fabricating novel glucose sensors with linear response up to 43.5mM. The analytical applications of the droplet-based microfluidic sensor were tested by using human blood serum samples. Reproducibility, interferences, and long-term stability of the modiﬁed electrode were also investigated. The present approach shows the feasibility and great potentials in constructing highly sensitive and low-consumption sensors in the field of droplet microfluidics.
authors.affiliation: Department of chemistry, College of Sciences, Shanghai University, Shanghai 200444, China; Technical Center for Animal Plant and Food Inspection and Quarantine, Shanghai Entry-Exit Inspection and Quarantine Bureau , Shanghai 200135, China; School of Materials Science and Engineering, Shanghai University, Shanghai, China.
authors.forename: Shuqing
authors.initials: S
authors.lastname: Gu
authors.affiliation: Department of chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
authors.forename: Youlan
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Department of chemistry, College of Sciences, Shanghai University, Shanghai 200444, China; School of Materials Science and Engineering, Shanghai University, Shanghai, China. Electronic address: wdingyp@sina.com.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.affiliation: School of Life Sciences, Shanghai University, Shanghai, China.
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Song
authors.affiliation: School of Life Sciences, Shanghai University, Shanghai, China.
authors.forename: Jinhua
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Tongji University, Shanghai 200092, China.
authors.forename: Qingsheng
authors.initials: Q
authors.lastname: Wu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D001786:Blood Glucose / Q000032:analysis* / Q000737:chemistry; D003217:Conductometry / Q000295:instrumentation*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005949:Glucose Oxidase / Q000737:chemistry*; D008839:Microelectrodes; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D010984:Platinum / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D001786:Blood Glucose; D004800:Enzymes, Immobilized; D010984:Platinum; D005949:Glucose Oxidase
keywords: Droplet; Glucose oxidase; Microfluidic; Pt-black microelectrode; Sensor