A label-free multicolor colorimetric and fluorescence dual mode biosensing of HIV-1 DNA based on the bifunctional NiFeO@UiO-66 nanozyme.

Finding the DNA of the human immune deficiency virus (HIV) with simple and sensitive detection is the main challenge in early diagnosis of AIDS. Herein, two-point separation strategies based on the colorimetric and fluorescence are introduced. The naked-eye qualitative and semiquantitative colorimetric, and also accuracy fluorescence quantification of HIV-1 DNA were applied using label-free NiFeO@UiO-66 nanozyme with both functions of peroxidase-mimetic like and emitting fluorescence. The DNA probe-conjugated nanozyme is employed to hybridize a sequence of HIV-1. NiFeO@UiO-66 nanozymes catalyze the decomposition of HO to OH which can produce a remarkable fluorescent product 2-hydroxyterephthalic acid (TAOH) by the oxidation of the bridging ligand of weakly fluorescent terephthalic acid (TA). The accessibility of HO toward confined-NiFeO MNPs was reduced by increasing the HIV-1 target DNA concentration, resulting in the fluorescence intensity of TAOH being decreased. Meanwhile, remaining the unreacted HO was transferred an acidic colorimetric solution containing FeSO and gold nanorods (AuNRs). Increasing the amount of HO available for longitudinal etching of AuNRs due to •OH-generating Fe-catalyzed HO is reponsible for different colors from brownish to colorless depending on the HIV-1 target DNA concentration. The fluorescence intensity and obtained colors have offered the sensitive biosensing methods with a linear range from 0.05 to 300 and 1-200 pM, respectively with a detection limit as low as 1 fM. Our study revealed that the applied sensing assay provides a cost-effective and straightforward qualitative, semiquantitative, and sensitive quantitation visible monitoring without the necessity of high-end instruments for HIV-1 detection in a human blood plasma/serum samples.