Perovskite QD based paper microfluidic device for simultaneous detection of lung cancer biomarkers – Carcinoembryonic antigen and neuron specific enolase

This work reports the microfabricated paper based analytical device (mPADs) for fluorometric detection of lung cancer biomarkers Carcinoembryonic antigen (CEA) and Neuron specific enolase (NSE) simultaneously. The device is patterned by wax printing on the paper that features two closed circular assay zone, connected to one sample zone through the grooved microfluidic channels for analyte flow. CsPbI3 perovskite quantum dots (IPQDs) were phase engineered (PE) for the first time to make it compatible in aqueous and biological medium. As a proof of concept, these PE- IPQDs along with PE CsPbBr3 perovskite quantum dots (BPQDS) were surface modified with streptavidin and conjugated to specific antibodies for demonstration of multiplexing, via sandwich type immunoassay. In addition to offering benefits of being less expensive, portable, enabling robust and facile operations, these developed mPADs exhibit specific and simultaneous detection of CEA and NSE lung cancer biomarkers. A linear response with a detection limit 0.095 ng/mL and 30.0 ng/mL was achieved for CEA and NSE respectively and while it was 0.12 ng/mL and 32 ng/mL for simultaneous detection. This mPAD device (with negligible toxicity of the probe) thus combines the high-throughput capabilities of a microfluidic network with the high sensitivity and multicolour imaging ability offered by perovskite QDs. This can become a promising diagnostic tool if extended for detection of other proteins or biomarkers involved in environmental and food safety research.