Electrochemical detection of acute renal disease biomarker by Galinstan nanoparticles interfaced to bilayer polymeric structured dirhenium heptoxide film.

This work describes a facile fabrication of an efficient electrochemical sensor utilizing sonication-derived Galinstan nanoparticles (Galinstan NPs) interfaced to annealed dirhenium heptoxide (Re2O7) thin-film on Silicon (Si) for the quantitative detection of the most promising acute renal disease biomarker Neutrophil Gelatinase Associated Lipocalin (NGAL). Under optimized preconditions, the anti-NGAL antibodies were immobilized on the Galinstan NPs/Re2O7/Si electrode by carbodiimide crosslinking to detect NGAL. The composition, morphology, and structural properties of the electrode were elucidated by various physical characterizations. The sensor obtained a high sensitivity (0.018 µA-1ng-1ml-1, R2 = 0.99) in differential pulse voltammetry and a minimum detection limit (2.14 ng ml-1) in electrochemical impedance spectroscopy for a wide range of NGAL concentrations (25-650 ng ml-1) with high selectivity and stability. The intensified performance of the sensor was achieved by the summed-up electron transfer from the Re2O7 film to Galinstan NPs and Galinstan NPs to the electroactive reactants. Additionally, the outer 2D gallium oxide (Ga2O3) layer of Galinstan Nps enhanced the redox activities, whereas the metallic core contributed to the magnificent conductivity. The excellent recovery rates of the sensor for different concentrations of NGAL measured in commercial human serum by the standard addition method assured the feasibility of the sensor.

Integrated Vortex Micropumps and Active Micromixers in Polymer Substrates for Automating Bio-fluidic Manipulation.

This paper presents a microfluidic mixing module array developed for bio-fluid/chemical delivery and mixing. Vortex micropumps, microchannels and pillared-surface diaphragm (PSD) active micromixers were successfully integrated into a single polymer-based microfluidic chip, consisting of three mixing modules. The pumping characteristics of the vortex micropump were investigated with both analytical and experimental results. Experiments were also conducted to examine the factors affecting the PSD-based mixing. The integrated mixing module further demonstrated the feasibility of chemical mixing and concentration control. An integrated fluidic system was shown successfully to deliver bio-fluid for real-time SPR based detection. A computer-controlled fluid manipulation system is also proposed for the real-time microfluidic operation control. The digitally controllability of the pumping and mixing operations could potentially improve the accuracy and efficiency, and hence, the functionality of the integrated microfluidic system.