TL;DR
A dual-mode aptasensor based on magnetic separation with a sequential signal conversion mechanism is developed for sensitive and specific detection of HepG2 cells, exhibiting high specificity for HepG2 over other tumor cells.
A ratiometric fluorescence nanosensor using dual-emission CdTe quantum dots (R-QDs) for sensitive detection of APE1, a DNA repair enzyme and cancer biomarker, successfully detected APE1 in breast cancer cell lysates with good linearity and recovery rates.
A dual-mode colorimetric–photothermal LFIA platform was successfully constructed for the detection of thrombosis-related biomarkers, including thrombomodulin and α2-plasmin inhibitor–plasmin complex, in clinical serum samples, enhancing analytical sensitivity and reliability.
It is shown that transforming a molecular ECL luminophore into a colloidal nanoprobe can increase its cellular uptake as well as enhance its application potential via both fluorescence and ECL.
The rapid and accurate detection of chlorpyrifos (CPF), a widely used pesticide in agricultural products, is crucial for food safety assurance. While traditional methods like HPLC and GC-MS are accurate, they remain costly, slow, and lack portability. Herein, an ultrasensitive magnetic biosensing platform was developed for the ratiometric detection of CPF in tea by integrating surface-enhanced Raman spectroscopy (SERS) with an aptamer-based recognition strategy. The platform employed a competitive displacement mechanism, where specific binding between aptamer and CPF triggered the release of signal probes upon magnetic separation. This process altered the Raman intensity ratio of two reporter molecules (4-MPY and 4-MBN). The ratiometric sensing approach, combined with magnetic separation, improved operational convenience and reduced matrix interference from complex samples. Furthermore, the platform exhibited a wide linear detection range (10-9 M to 10-4 M) with a limit of detection (LOD) of 1.4 × 10-6 mg/kg. It demonstrated high sensitivity, stability, reproducibility and specificity across six tea varieties, offering an effective solution for detecting pesticide residues in complex food matrices.
Self-validated bioanalytical systems based on mechanistically orthogonal dual-mode transduction have attracted considerable interest, yet their development critically depends on multifunctional heterostructure materials that simultaneously enable efficient charge separation and well-resolved dual-emission output. Herein, a dual-mode photoelectrochemical/ratiometric fluorescence (PEC/FL) platform was constructed for sensitive dopamine (DA) determination based on a ternary MXene/Eu,Gd-CQDs/B,GQDs-g-C3N4 heterostructure (MEG). The MXene-mediated cascade interfacial architecture enabled efficient separation and rapid transport of photogenerated charge carriers for PEC signal amplification, while retaining well-resolved and reproducible dual-emission characteristics suitable for ratiometric fluorescence detection. In the PEC mode, the photocurrent increased with DA concentration, giving two separated linear calibration ranges of 0.01-0.20 μM and 10-500 μM, with a limit of detection (LOD) of 2.8 nM. In the FL mode, DA produced a wavelength-dependent ratiometric response dominated by progressive quenching of the 445 nm emission, yielding a concentration-dependent F365/F445 ratiometric response over 0.05-1.0 μM with an LOD of 38 nM. The complementary transduction mechanisms enabled mutual verification between the two modes, thereby reducing the risk of false-positive or false-negative interpretation associated with reliance on a single readout. Both modalities demonstrated excellent selectivity toward DA over common coexisting species, together with satisfactory operational stability and reproducibility. Practical applicability was validated in fetal bovine serum and river water samples, yielding recoveries of 96.8-104.2% with relative standard deviations below 5%. These results demonstrate that the MEG-based dual-readout strategy offers a robust, self-validated approach to reliable bioanalysis in complex matrices, using DA as a model system.