Portable Thermal Management Platform for Synthesis of ZnO Nanoparticle in a Microfluidic Device: Validated for Electrochemical Sensing and Glucose Fuel Cell Applications

Nanoparticles have become omnipresent as they have distinctively diverse properties from their bulk counterparts. They find a considerable research interest in numerous biological, biomedical, biopharmaceutical, and biochemical applications. The productivity and structure of nanoparticles are deeply reliant on the method used for their synthesis. The classical hydrothermal method needs massive and expensive temperature controller instruments, a huge amount of reagents, and specific autoclaves for their synthesis. With this motivation, herein, an automated, integrated, and miniaturized thermal monitoring system has been designed and developed for producing nanoparticle-on-chip (NoC) in a microfluidic platform. Herein, Zinc oxide (ZnO) nanoparticles were synthesized. The device comprises a microcontroller, self-designed switching circuit, cartridge heater, and thermocouple. The device, with dimensions 78 × 75 × 40 mm3, has benefits such as portability, easy-to-use, amenability to geotagged data logging, and inexpensive. The device showcased the temperature sensitivity of ± 0.5 °C. A polymethyl methacrylate (PMMA)-based microfluidic device, with a suitable microreactor, was fabricated using the CO2 laser ablation technique. ZnO nanoparticles were successfully synthesized at 95 °C within 60 min and were subjected to several characterization techniques to manifest their crystographic, elemental, morphologic, and spectroscopic properties. As a proof-of-principle, the produced ZnO nanoparticles were validated for electrocatalytic sensing of hydrazine and uric acid, and as a catalyst in an enzymatic glucose biofuel cell (EBFC) to test its efficiency. The proposed microfluidic thermal system can be utilized for carrying out numerous temperature-based reactions and analyses.