A Fluorescence Biosensor Based on Carbon Quantum Dots Prepared from Pomegranate Peel and T-Hg-T Mismatch for Hg Detection.

Mercury ions (Hg) can cause damage to human health, and thus, the study of the detection of Hg is extraordinarily important in daily life. This work reported a fluorescence biosensor for the detection of Hg. The key point of this strategy was that the fluorescence of carbon quantum dots made from pomegranate peel (P-CQDs) was quenched by hemin, and restored after G-quadruplex binding with hemin. The presence of Hg caused thymine (T)-rich DNA fragments to form T-Hg-T mismatches, and this change allowed the release of G-quadruplex. G-quadruplex could change the fluorescence of hemin/P-CQDs. P-CQDs exhibited excellent properties through characterization analysis, such as transmission electron microscope, X-ray photoelectron spectroscopy and Fourier transform infrared. This proposed fluorescence detection strategy established the linear ranges of Hg from 1 nM to 50 nM. In conclusion, this simple biosensor had the advantages of strong sensitivity, high selectivity, and low cost for Hg detection in environmental water samples.