Reconfiguration/Immobilization "Dual-Free" Self-Powered Multiplex Photoelectrochemical Strategy for Dual Magnetic...

Despite significant advances in single-interface multiplex photoelectrochemical (PEC) sensors, their potential in high-throughput complex sample analysis is still limited by time-consuming immobilization and cumbersome surface reconfiguration procedures. Particularly for the rapidly growing demand for point-of-care testing, there is an urgent need to explore fast, low-consumption, and sustainable multisignal differentiation approaches ready for implantation into a portable sensor. Herein, a dual magnetic bead-mediated reconfiguration/immobilization "dual-free" strategy is proposed for self-powered PEC sensing of multiple targets on a single electrode. The dual magnetic bead-mediated dimension-differentiated system is formed by two size-differentiated magnetic beads (MBs) and methylene blue-loaded liposomes (MLLs). A large MB is involved in obtaining the MLL signal label via magnetic separation, which modulates the electron transfer mechanism and generates a detection signal. After physically controlled release, the small MB (second signal label) magnetically anchors at the electrode interface to produce another detection signal. By circumventing chemical immobilization and interface reconfiguration, the "dual-free" strategy realizes the rapid, low-cost, sequential, and nondestructive detection of coexisting antibiotics (kanamycin and tobramycin). To further reduce the dimensions and power consumption of the sensing device, a self-powered dual-photoelectrode system is established and instrumented. The reconfiguration/immobilization "dual-free" self-powered sensor eliminates cross-interference, preserves electrode integrity, and avoids external power requirements, thereby pioneering a universal approach for developing miniaturized PEC sensors with great promise for point-of-care testing.