About the Seminar:
The diagnosis of many human diseases is driven by the detection of one or more specific biomarkers. Rapid and sensitive detection of these biomarkers is crucial in preventing further illness and/or the spread of the diseases within the individual and to other people. Microfluidic-based electrochemical immunoassays for biomarker detection have been explored as a practical alternative to time-consuming and expensive techniques such as polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA), which require highly trained personnel. An important component in the fabrication of microfluidic devices is the electrode. Screen-printed carbon electrodes (SPCEs) are widely used due to their potential for mass production, and ease of printing directly onto the microfluidic device. Relatively recently, laser-induced graphene (LIG) has been explored for use as an electrode material in electrochemical biosensors, but there are limited examples of its use in microfluidic devices. Production of LIG electrodes is easy when compared to that of SPCEs, requiring only a CO2 laser cutter and a polymeric substrate, like polyimide, capable of producing LIG. Fabrication of the electrodes occurs instantaneously through direct laser writing onto the substrate, where high localized temperatures induce the conversion of the polymeric material into graphene. LIG electrodes also have excellent electrochemical properties that make them superior to traditional SPCEs. Their porous and highly graphitic nature gives them high conductivity, and electroactive surface areas much larger than SPCEs. The automated production of LIG electrodes leads to high reproducibility (<2% RSD) when they are characterized using electrochemical techniques, while the hands-on nature of the screen-printing process introduces more error (up to 15%), decreasing performance. Future work involves the development of a new process for implementing LIG electrodes into a microfluidic device for the subsequent execution of electrochemical immunoassays.
