Figure 4.
3D printed microfluidic biosensor and organs-on-a-chip. a) 3D printed needle-type microfluidic glutamate sensor consisting of three electrodes wherein the working electrode is made of platinum NPs, CNTs, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT.PSS). The biochemical reaction shows the generation of electrons by oxygen (O2) and hydrogen peroxide (H2O2) reduction in presence of glutamate oxidase enzyme.[126] Reproduced with permission.[126] Copyright 2019, Elsevier. b) A schematic and an optical image of a 3D printed modular microfluidic sensor with reusable electrodes. The micrographs show gold and silver wire secured with C-7 epoxy and a calibration plot for the detection O2 concentration (parts-per-million) in presence of buffer (HBSS) with red blood cell counts,[38] Reproduced with permission.[38] Copyright 2014, Royal Society of Chemistry. c–e) 3D printed organ-on-a-chip. The optical image shows a perpendicular assembly of microchannel and tri-chamber components of the organ-on-a-chip. The micrograph shows a single channel of superior cervical ganglia (SCG) neurons and axons in chamber 1.[127]