MXene-based fluorescent aptasensors: advances and prospects in diagnostics and environmental monitoring

MXene-based fluorescent aptasensors leverage the synergistic integration of the intrinsic physicochemical properties of MXenes, including tunable surface chemistry, broad-spectrum optical absorption, and superior fluorescence quenching efficiency, with the molecular recognition capabilities and strong binding affinity of aptamers. These two-dimensional transition metal carbides and nitrides efficiently suppress background fluorescence in dye-labeled aptamer systems through electrostatic interactions and π-π stacking. In the absence of the target analyte, the aptamers adsorb onto the MXene surface, facilitating non-radiative energy transfer and thereby suppressing the signal. Upon specific target recognition, a conformational rearrangement of the aptamer reduces its surface affinity, leading to desorption and subsequent fluorescence recovery via a target-induced "signal-on" mechanism. Such platforms demonstrate ultra-low detection limits, excellent selectivity, and modular adaptability for the detection of a broad spectrum of analytes, including clinical biomarkers, pathogenic microorganisms, environmental toxins, and heavy metal ions. This comprehensive review systematically summarises the mechanistic foundations of MXene-aptamer interactions, recent advancements in analytical applications, and emerging directions for translational development in biomedical diagnostics and environmental monitoring.