Metal-organic frameworks (MOFs) and MOF composites based biosensors

Metal-organic frameworks (MOFs) are novel hybrid materials that have shown unique opportunities in biosensors. The well-defined geometry, porosity, structural tunability, stability, and ease of functionalization of MOFs are particularly advantageous for biosensing. This review outlines the progress in the design and function of MOF based biosensors, focusing on recent developments. We have concentrated on MOF and MOF composite based optical and electrochemical biosensors, which have appeared in a good number of publications in the literature and enriched the field of biosensors. The biologically essential transition metals and relevant lanthanide metal based MOFs have been reviewed. These have shown efficient analyte detection with fast response for the transducer, which includes electrochemical and optical signals for analyte detection by fluctuating the signals or enhancing/quenching the luminescent intensity. The biosensors based on MOF composites are also reviewed, where additional features, such as enhanced stability, sensitivity, and specificity, have been realized by adopting a synergistic combination of MOFs with selected functional materials. We also review the bioreceptor-coupled MOF sensors, where the bioreceptors (enzyme, antibody, nucleic acid, and the aptamer) immobilized on the MOF matrix proficiently detect the desired bioanalyte in the presence of a transducer. Finally, we present the overall summary, challenges, and future perspective in biosensors based on MOFs and related composite materials.