A Fully Split-Type PEC Sensing Driven by Orthogonal DNA Nanoprobes and Phosphate-Induced Site-Occupation Effect for Multiplexed Detection

To overcome limitations of conventional photoelectrochemical (PEC) aptasensors─such as intricate electrode modification, interfacial interference, and restricted multiplex detection capability─a "fully split-type" PEC sensing strategy was developed based on DNA molecular logic gates and a phosphate-driven release mechanism. Programmable DNA logic gates operate entirely in a homogeneous solution, allowing simultaneous recognition of multiple targets and release of signaling probes without external regulation. Phosphate ions further competitively displace DNA probes from a zirconium-based metal-organic frameworks (MOFs) signal tag (UiO-66-TCPP). The released MOFs are directly drop-coated onto bare electrodes to yield a background-free PEC signal. By moving all recognition steps into solution and removing the need for electrode modification, this approach minimizes interface-related issues and simplifies detection to a single drop-casting step. The resulting platform offers improved simplicity, stability, and detection efficiency while maintaining high selectivity and intrinsic programmability. Meanwhile, this universal bare-electrode readout is readily compatible with miniaturized systems, offering a versatile and practical route toward multiplexed and portable PEC bioanalysis.