Development of glass-based microfluidic devices: A review on its fabrication and biologic applications

The advent of glass-based microfluidic devices further revolutionized in microfluidic technology due to the several advantageous properties in terms of photonics, electronics, and thermochemistry, compared to silicon, PDMS and paper. In this review article, we discuss the glass materials in comparison with inorganic, organic polymeric and paper materials for the fabrication of microfluidic devices and the suitability, benefits, applicability of their applications. We highlight the performance enhancement of glass achieved via hybrid fabrication with advanced polymers. For this comprehensive overview of the different materials for the fabrication and applications of microfluidic devices, we consider recent advances in the selected applications of glass material-based microfluidics in sensing and biomedical applications, such as Raman spectroscopy, mass spectroscopy, optical detection methods, embedded glass microfluidics for oil and gas, point-of-care diagnostics, cell analysis, nucleic acid assay, immunoassay analysis and drug delivery. Our review concludes by summarizing the future challenges and developments of these glass-based microfluidic devices

2.6 V Aqueous Battery with a Freely Diffusing Electron Acceptor

Here we show a strategy to expand the working voltage of aqueous metal batteries beyond the thermodynamic limit of 1.23 V by modifying the interfacial chemistry existing at the cathode/electrolyte interface. Highly nonwettable carbon nanoparticle cathode/electrolyte interface with a freely diffusing electron acceptor kinetically muted water decomposition due to reduced contact between water and the electrode, expanding the working voltage far beyond 1.23 V. Zn battery equipped with hydrophobic carbon nanoparticle cathode delivered an open-circuit voltage (OCV) of 2.6 V with capacity (∼930 mAh/g), energy (∼2420 Wh/kg @ 50 mA/cm²), and power densities (∼83 W/kg) remarkably higher than conventional Pt-based aqueous Zn-air batteries (OCV = 1.5 V, ∼650 mAh/g, ∼1161 Wh/kg, and ∼43 W/kg). When probed with in situ and ex situ FTIR spectroelectrochemistry and galvanostatic intermittent titration technique, wettable carbon particles (contact angle = ∼20°) are found to catalyze parasitic oxygen evolution reaction, while their nonwettable counterpart (contact angle = ∼117°) dominantly catalyzed electron acceptor’s redox reaction by inhibiting any such parasitic chemistry. Zn batteries equipped with carbon cathode contribute to a Pt-free battery having a closed cathode, addressing the complexity of carbonate clogging and electrolyte evaporation often encountered in open-air batteries, and could be used to power electrical appliances

Redox Active Binary Logic Gate Circuit for Homeland Security

Bipolar junction transistors are at the frontiers of modern electronics owing to their discrete voltage regulated operational levels. Here we report a redox active binary logic gate (RLG) which can store a “0” and “1” with distinct operational levels, albeit without an external voltage stimuli. In the RLG, a shorted configuration of half-cell electrodes provided the logic low level and decoupled configuration relaxed the system to the logic high level due to self-charge injection into the redox active polymeric system. Galvanostatic intermittent titration and electrochemical quartz crystal microbalance studies indicate the kinetics of self-charge injection are quite faster and sustainable in polypyrrole based RLG, recovering more than 70% signal in just 14 s with minor signal reduction at the end of 10000 cycles. These remarkable properties of RLGs are extended to design a security sensor which can detect and count intruders in a locality with decent precision and switching speed

Redox Active Binary Logic Gate Circuit for Homeland Security

Bipolar junction transistors are at the frontiers of modern electronics owing to their discrete voltage regulated operational levels. Here we report a redox active binary logic gate (RLG) which can store a “0” and “1” with distinct operational levels, albeit without an external voltage stimuli. In the RLG, a shorted configuration of half-cell electrodes provided the logic low level and decoupled configuration relaxed the system to the logic high level due to self-charge injection into the redox active polymeric system. Galvanostatic intermittent titration and electrochemical quartz crystal microbalance studies indicate the kinetics of self-charge injection are quite faster and sustainable in polypyrrole based RLG, recovering more than 70% signal in just 14 s with minor signal reduction at the end of 10000 cycles. These remarkable properties of RLGs are extended to design a security sensor which can detect and count intruders in a locality with decent precision and switching speed