Metal−organic frameworks (MOFs), synthesized by assembling metal nods with organic linkers, are highly ordered crystalline materials. MOFs have attracted much attention for applications in electrochemical sensors, because of their unique chemical and physical properties including ultrahigh porosity, large surface area, tunable structure, and high thermal and chemical stability. In particular, redox and catalytic active sites introduced by use of active metal ions and/or ligands endow MOFs with the functions required in electrochemical sensing. Moreover, precise chemical modification of functional molecules and immobilization with metal nanoparticles, carbon nanostructures, and biomolecules could promote their electrochemical performances. In this Review, we focus on recent progress achieved in MOF research with respect to general sensing principles and analytical performances of electrochemical sensors. The evaluation and challenges governing the detection of the assays are also discussed.

The Applications of Metal−Organic Frameworks in Electrochemical Sensors

Metal–organic frameworks for biosensing and bioimaging applications

Porphyrins and porphyrin derivatives have been widely explored for various applications owing to their excellent photophysical and electrochemical properties. However, inherent shortcomings, such as instability and self-quenching under physiological conditions, limit their biomedical applications. In recent years, metal-organic frameworks (MOFs) have received increasing attention. The construction of porphyrin-based MOFs by introducing porphyrin molecules into MOFs or using porphyrins as organic linkers to form MOFs can combine the unique features of porphyrins and MOFs as well as overcome the limitations of porphyrins. This Review summarizes important synthesis strategies for porphyrin-based MOFs including porphyrin@MOFs, porphyrinic MOFs, and composite porphyrinic MOFs, and highlights recent achievements and progress in the development of porphyrin-based MOFs for biomedical applications in tumor therapy and biosensing. Finally, the challenges and prospects presented by this class of emerging materials for biomedical applications are discussed.

https://onlinelibrary.wiley.com/doi/epdf/10.1002/anie.201909880

Porphyrin‐Based Metal–Organic Frameworks for Biomedical Applications

Recent progress in the design fabrication of metal-organic frameworks-based nanozymes and their applications to sensing and cancer therapy.

Principles and applications of photoelectrochemical sensing strategies based on biofunctionalized nanostructures.

A simple and rapid photoelectrochemical (PEC) sensor was developed for the label-free detection of a phosphoprotein (α-casein) based on a zirconium based porphyrinic metal–organic framework (MOF), PCN-222, which exhibited an enhanced photocurrent response toward dopamine under the O2-saturated aqueous media. In this work, in terms of PEC measurements and cyclic voltammetry, the PEC behaviors of PCN-222 in aqueous media were thoroughly investigated for the first time. Additionally, in the virtue of the steric hindrance effect from the coordination of the phosphate groups and inorganic Zr–O clusters as binding sites in PCN-222, this biosensor showed high sensitivity for detecting α-casein and the limit of detection (LOD) was estimated to be 0.13 μg mL–1. Moreover, the proposed method provides a promising platform for clinic diagnostic and therapeutics.

Zirconium-Based Porphyrinic Metal–Organic Framework (PCN-222): Enhanced Photoelectrochemical Response and Its Application for Label-Free Phosphoprotein Detection

Yu-Hong Zhuang

Papers

Zirconium-Based Porphyrinic Metal–Organic Framework (PCN-222): Enhanced Photoelectrochemical Response and Its Application for Label-Free Phosphoprotein Detection