Aptamer-based fluorescent and visual biosensor for multiplexed monitoring of cancer cells in microfluidic paper-based analytical devices

In this work, we report a rapid, facile, portable, disposable and low-cost fluorescence and visual method for multiplexed monitoring of cancer cells using graphene oxide (GO)-based aptameric nanosensor in microfluidic paper-based analytical devices. This method has combined the exceptional quenching capability of GO and an aptamer with high specificity and affinity employed as the molecular recognition element. The quantum dots coated mesoporous silica nanoparticles labeled aptamers in a flexible single stranded state could be adsorbed on the surface of GO, and the fluorescence was quenched via Forster resonance energy transfer, with subsequent recovery of the fluorescence upon addition of target cells. Furthermore, the design of sensors for other cancer cells only requires change in the recognition element for the target cell and different colored quantum dots. More importantly, three different cancer cells can be simultaneously determined with a single excitation light. The sensitivity and selectivity of this method for GO-based sensing were extremely high. The color changes could be clearly monitored with the naked eye. And their linear range were from 180 to 8 x 10(7), 210 to 7 x 10(7), 200 to 7 x 10(7) cells mL(-1) and detection limit were 6270 and 65 cells mL(-1) for MCF-7, HL-60, and K562 cells, respectively. It could be applied in clinical sample analysis with a satisfactory result. Therefore, GO-based aptameric nanosensor is highly promising for potential applications in the sensitive monitoring of multiple cancer cells for biomedical research and medical diagnostics. (C) 2016 Elsevier B.V. All rights reserved.