This review highlights recent advances towards non-invasive and continuous glucose monitoring devices, with a particular focus placed on monitoring glucose concentrations in alternative physiological fluids to blood.

Sodium-selective coated wire electrodes (CWE) and solid contact (SC) electrodes have been constructed and Investigated. The CWE Is based on the application of a poly(vinyl chloride) (PVC) membrane Incorporating the sodium-selective Ionophore tetraethyl ester of p-/erf-butylcallx[4]arene onto the surface of a platinum disk. The SC electrode Is based on the use of a conducting polymer, polypyrrole (PPy), doped with NaBF« as the mediating layer between platinum and the same PVC membrane as above. Nernstlan responses have been obtained for both electrodes and comparable selectlvlties to that of a conventional lon-selectlve electrode (ISE) based on the same Ionophore. Impedance measurements of the PPy and PVC layers and potentlometrlc studies of the membranes have been used to Investigate the mechanism of the charge transfer of the systems.

The bulk of the currently available biosensing techniques often require complex liquid handling, and thus suffer from problems associated with leakage and contamination. We demonstrate the use of an organic electrochemical transistor for detection of lactate (an essential analyte in physiological measurements of athlete performance) by integration of a room temperature ionic liquid in a gelformat, as a solid-state electrolyte.

A smartphone application, called CAnal, was developed as a colorimetric analyzer in paper-based devices for sensitive and selective determination of mercury(II) in water samples. Measurement on the double layer of a microfluidic paper-based analytical device (μPAD) fabricated by alkyl ketene dimer (AKD)-inkjet printing technique with special design doped with unmodified silver nanoparticles (AgNPs) onto the detection zones was performed by monitoring the gray intensity in the blue channel of AgNPs, which disintegrated when exposed to mercury(II) on μPAD. Under the optimized conditions, the developed approach showed high sensitivity, low limit of detection (0.003 mg L-1 , 3SD blank/slope of the calibration curve), small sample volume uptake (two times of 2 μL), and short analysis time. The linearity range of this technique ranged from 0.01 to 10 mg L-1 (r 2 = 0.993). Furthermore, practical analysis of various water samples was also demonstrated to have acceptable performance that was in agreement with the data from cold vapor atomic absorption spectrophotometry (CV-AAS), a conventional method. The proposed technique allows for a rapid, simple (instant report of the final mercury(II) concentration in water samples via smartphone display), sensitive, selective, and on-site analysis with high sample throughput (48 samples h-1 , n = 3) of trace mercury(II) in water samples, which is suitable for end users who are unskilled in analyzing mercury(II) in water samples.