An integrated microfluidic chip for synchronous drug loading, separation and detection of plasma exosomes

Exosomes have gained increasing attention as robust, biocompatible carriers for targeted therapy. However, current techniques for exosome drug loading suffer from low drug loading efficiency and substantial exosome loss during repeated purification and quantification processes. Here, we present an integrated microfluidic chip (IMC) that streamlines drug loading, separation, and electrochemical detection of exosomes from plasma in a single device. In this design, the three-dimensional (3D) macroporous scaffold and the magnetoresponsive electrode are successfully assembled into the modeling microchip, playing the functions of "3D chaotic flow mixer", "magnetic separator" and "electrochemical detector". When plasma, doxorubicin (DOX), boron clusters and immunomagnetic nanoprobes (IMPs) are simultaneously injected into the IMC, the exosomes are loaded with DOX-boron cluster (EDB) complexes and synchronously recognized by IMPs in the "3D chaotic flow mixer". Our strategy exhibits high DOX loading efficiency owing to the superchaotropic effect of boron clusters and enhanced immunolabeling efficiency by the thorough mixing of the 3D scaffold. Meanwhile, the novel magnetoresponsive electrode enables magnetic separation and real-time, enzyme-linked immunoelectrochemical quantification of exosomes, thereby simplifying the workflow from drug loading to quantification. The resulting EDB in combination with magnetic hyperthermia achieves up to 90% cell-killing efficiency against DOX-resistant breast cancer cells. Overall, our system could simultaneously realize the enhanced DOX loading into exosomes, efficient magnetic immunoseparation of exosomes, and sensitive electrochemical quantification of exosomes, offering a promising approach for autologous exosome-based drug delivery for cancer treatment.