Integrated ZnO nanoparticles on paper-based microfluidic: Toward efficient analytical device for glucose detection based on impedance and FTIR measurement

Microfluidic paper-based analytical devices decorated with ZnO nanospherical (nanoSPs) aggregates (ZnO-μPAD) for glucose detection have been fabricated. ZnO nanoSPs were prepared by wet chemical synthesis and integrated on the optimized geometry of ZnO-μPAD has 0.2 and 0.4 mm of channel width and length, respectively. Glucose detection measurements were based on electrochemical and infrared transmission measurements. The glucose concentrations were adjusted as 5, 6.5, and 9 mmol, i.e. typical glucose level for normal, pre-diabetes and diabetes, in a mixture of ringer lactate as simulated biological fluid and red blood cells. ZnO nanoSPs in this study possess an average aggregate size of 160 nm formed by clustered ∼ 18 nm crystallite size and ordered porous matrix as well as a surface area of 15 m²·g^-1.The separation process of the glucose sample on ZnO-μPAD requires approximately 45 s. The glucose detection results show that both electrochemical-based and FTIR-based measurements perform a linear measurement system (R² of 0.81 to 0.99) with a relatively high sensitivity. A linearly decreasing impedance spanning from 2.2 - 0.6 Ohm and linearly increasing ΔIR transmission spanning from 3 - 19% are obtained for glucose level ranging from 5 - 9 mmol.