Electromicrofluidic device with integrated PDMS microchannel and laser-induced graphene electrodes for electrochemical detection of cardiac biomarker in a point-of-care platform

By providing a facile and scalable alternative to otherwise complex and resource-intensive synthesis of graphene, laser-induced graphene (LIG) is spearheading the translation of graphene-based propositions to deployable technologies for societal benefit. LIG is a versatile and economical synthesis approach which is being used on a variety of substrates and in a multitude of applications-including miniaturized sensing systems. One aspect that has not been addressed thoroughly in LIG-based miniaturized sensing systems is its successful integration with microfluidics and its possible use in point-of-care settings. To further diversify the applications of LIG with integrated microfluidics, this work reports on the development of an integrated flexible microfluidics-LIG based electrochemical biosensor. The work describes the methodology to develop a polydimethylsiloxane-LIG scribed polyamide microfluidic device in a leakage-free flexible application. In view of the excellent electrical and electrochemical properties of LIG, such device has been employed for electrochemical biosensing. The biosensing capabilities of the microfluidic device were validated via sensing of cardiac troponin I-a gold standard cardiac biomarker for early identification of acute myocardial infarction (AMI). The developed biosensor demonstrated a detection and quantification limit of 45.33 pg ml(-1) and 151.10 pg ml(-1) respectively, which are in clinically significant ranges for diagnosis of AMI. The mu-fluidic biosensor was also analyzed for stability and interference with other cardiac biomarkers. The developed integrated mu-fluidic electrochemical biosensor was evaluated for possible point-of-source applications in conjunction with a custom 3D printed peristaltic pump and smartphone-enabled miniaturized potentiostat.