2D magnetic MoS2-Fe3O4 hybrid nanostructures for ultrasensitive exosome detection in GMR sensor.

Exosome released from cells plays an important role in intercellular communication and show great clinical potential in early cancer screening and prognosis. Herein, an ultrasensitive Giant Magnetoresistance (GMR) biosensor was developed for exosome detection, which was based on 2D MoS2-Fe3O4 nanostructures (MOFE) as magnetic responsive probes for signal amplification. The MOFE can be readily synthesized with simple phase transfer method. Compared to pure Fe3O4 magnetic nanoparticles (MNPs), the layered MoS2 function as a template for recruiting high loading density of MNPs as magnetic probes. After modified by aptamer, we discover that the 2D magnetic MOFE hybrid nanostructures enable both multidentate targeting and multi-magnetic particle-based signal amplification, increasing the magnetic sensor performance, especially in sensitivity and output signal. Moreover, the 2D magnetic nanocomposites afford high selectivity and excellent reproducibility with detection limit of 100 exosomes in GMR sensor. Results demonstrate that the magnetic strategy based on 2D structures introduced here provide a new dimension for exosome detection, which show great potential of engineering 2D magnetic nanobioprobes for GMR based liquid biopsy application.