Orthogonal Dual-Signal Cooperative Sensing Platform via CDs@MIPs-Mediated Fluorescence Enhancement and Aptamer-Liposome Fusion-Triggered Photoelectrochemical Amplification

The development of dual-recognition and multisignal transduction sensing strategies is critical for achieving precise identification and ultrasensitive detection of small molecule contaminants. In this work, a fluorescence-photoelectrochemical (FL-PEC) "dual-signal on" sensing platform was presented based on a dual-recognition strategy combining molecularly imprinted polymers (MIPs) and aptamers. Specifically, the MIPs functionalized on the fluorescent carbon dots (CDs) (CDs@MIPs) served as the first recognition element, capturing target molecules and suppressing the photoinduced electron transfer (PET) effect, thereby triggering the fluorescence signal recovery (FL signal). The second recognition units consisted of target-specific aptamer-functionalized liposomes loaded with potassium ferricyanide (Apt@Lip-K3[Fe(CN)6]), quantitatively binding to the CDs@MIPs/target complex. Subsequent liposome lysis releases K3[Fe(CN)6], which acted as an electron acceptor to boost the photocurrent of CTAB@MAPbI3/ITO, generating a second photoelectrochemical signal increase (PEC signal). Using dibutyl phthalate (DBP) as a model contaminant, the dual-signal platform realized sensitive detection in the linear range of 0.1 nM-10.0 μM (FL) and 1.0 pM-0.1 μM (PEC), with detection limits of 71.30 pM (FL) and 0.648 pM (PEC) (S/N = 3), respectively. The MIPs-aptamer cooperative dual-recognition mechanism enabled complementary FL (rapid visual screening) and PEC (precise quantification) responses, ensuring cross-validated detection that minimizes false positives while enhancing sensitivity. The platform has also been applied for bisphenol A (BPA), another small molecule phenolic pollutant, showing its wide applicability as a universal platform for the detection of small molecule contaminants in food and environmental monitoring applications.