Smartphone-integrated colorimetric sensor for rapid detection of phenolic compounds based on the peroxidase-mimicking activity of copper/cerium-aspartic acid metal-organic framework.

A smartphone-integrated colorimetric sensor is introduced for the rapid detection of phenolic compounds, including 8-hydroquinone (HQ), p-nitrophenol (NP), and catechol (CC). This sensor relies on the peroxidase-mimicking activity of aspartate-based metal-organic frameworks (MOFs) such as Cu-Asp, Ce-Asp, and Cu/Ce-Asp. These MOFs facilitate the oxidation of a colorless substrate, 3,3',5,5'-tetramethylbenzidine (TMB), by reactive oxygen species (ROS) derived from hydrogen peroxide (HO), resulting in the formation of blue-colored oxidized TMB (ox-TMB).

A metal-phenolic coordination framework nanozyme exhibits dual enzyme mimicking activity and its application is effective for colorimetric detection of biomolecules.

Biomolecules play vital roles in many biological processes and diseases, making their identification crucial. Herein, we present a colorimetric sensing method for detecting biomolecules like cysteine (Cys), homocysteine (Hcy), and glutathione (GSH). This approach is based on a reaction system whereby colorless 3,3',5,5'-tetramethylbenzidine (TMB) undergoes catalytic oxidation to form blue-colored oxidized TMB (ox-TMB) in the presence of hydrogen peroxide (HO), utilizing the peroxidase and catalase-mimicking activities of metal-phenolic coordination frameworks (MPNs) of Cu-TA, Co-TA, and Fe-TA nanospheres.

A Turn-ON fluorometric biosensor based on ssDNA immobilized with a metal phenolic nanomaterial for the sequential detection of Pb(ii) and epirubicin cancer drug.

In this paper, we propose a fluorescent biosensor for the sequential detection of Pb ions and the cancer drug epirubicin (Epn) using the interactions between label-free guanine-rich ssDNA (LFGr-ssDNA), acridine orange (AO), and a metal-phenolic nanomaterial (, nano-monoclinic copper-tannic acid (NMc-CuTA)). An exploration of the sensing mechanism shows that LFGr-ssDNA and AO strongly adsorb on NMc-CuTA through π-π stacking and electrostatic interactions, and this results in the fluorescence quenching of AO. In order to sense the target Pb, initially, LFGr-ssDNA specifically binds with Pb ions to form a G4 complex (G-Pb-G base pair), which was released from the surface of NMc-CuTA with strong AO fluorescence enhancement (Turn-ON).