Highly Stable Fe/Co-TPY-MIL-88(NH₂) Metal–Organic Framework (MOF) in Enzymatic Cascade Reactions for Chemiluminescence-Based Detection of Extracellular Vesicles

Abstract

Metal−Organic Frameworks (MOFs) can deliver many advantages when acting as enzyme mimics to assist with signal amplification in molecular detection: they have abundant active catalytic sites per unit volume of the material; their structures and elemental compositions are highly tunable, and their high specific surface area and porous property can assist with target separation and enrichment. In the present work, we have demonstrated that, by adding the pore partition agent, 2,4,6-tris(4-pyridyl)pyridine (TPY) during synthesis of the bimetallic Fe/Co-MIL-88(NH 2 ) MOF to block the open metal sites, a highly porous MOF of Fe/Co-TPY-MIL-88(NH 2 ) can be produced. This material also exhibits high stability in basic solutions and biofluids and possesses high peroxidase-mimicking activity, which can be utilized to produce long-lasting chemiluminescence (CL) from luminol and H 2 O 2 . Moreover, acting as the peroxidase-mimic, the Fe/Co-TPY-MIL-88(NH 2 ) MOF can form the enzymatic cascade with glucose oxidase (GOx) for biomarker detection. When applied to detect extracellular vesicles (EVs), the MOF material and GOx are brought to the proximity on the EVs through two surface proteins, which triggers the enzyme cascade to produce high CL from glucose and luminol. EVs within the concentration range of 5 × 10 5 to 4 × 10 7 particles/mL can be detected with an LOD of 1 × 10 5 particles/mL, and the method can be used to analyze EV contents in human serum without sample preparation and EV purification. Overall, our work demonstrates that the high versatility and tunability of the MOF structures could bring in significant benefits to biosensing and enable ultrasensitive detection of biomarkers with judicious material designs.

Highly selective detection of 2,4-dinitrophenol by fluorescent NH2-MIL-125(Ti) via dual-parameter sensing technology

“…The utilization of fluorescence sensing has made significant progress in recent years for pollutant monitoring and the advancement of portable sensing equipment, owing to its exceptional sensitivity, cost-effectiveness, and prompt response. 10–12 With the advantages of tunable structure, 13–15 large surface area, 16,17 and abundant active sites, 18,19 luminescent metal–organic frameworks (LMOFs) 20 are widely used in fluorescence detection of diverse pollutants. 21–25 However, the majority of fluorescence sensing technology based on LMOFs primarily relies on single-parameter indicators to detect 2,4-DNP.…”

Buoyant Metal–Organic Framework Corona-Driven Fast Isolation and Ultrasensitive Profiling of Circulating Extracellular Vesicles

“…Currently, many isolation methods (e.g., ultracentrifugation, coprecipitation, and size exclusion), and detection techniques, such as optical, electrical, and acoustic sensors, − have been broadly deployed in EV assays, whereas they stress on either EV enrichment or quantification. , Although bioaffinity magnetic particles and microfluidics have advanced EV isolation and detection, − they usually require costly antibodies (e.g., antibody cocktail) and are heavily relied on microfabrication or external forces, , thus limiting the usage of EVs in clinical settings in a more competent fashion. In comparison, transition-metal elements show cost-effective coordinative affinity toward EVs. − Based on such affinities, Ti-based metal oxides (TiO 2 ) and Zr-based metal–organic frameworks (Zr-MOFs) have been exploited for EV capture, − whereas the unordered accumulation or overdispersion of these particles largely degrades downstream in situ, on-site, and multiplexed EV analysis.…”

Ultrafast Response in Nonenzymatic Electrochemical Glucose Sensing with Ni(II)-MOFs by Dimensional Manipulation

“…Metal–organic frameworks (MOFs) represent a class of crystalline porous materials with periodic extended structures, which consist of metal nodes (metal ions or metal clusters) self-assembled with organic ligands through coordination bonds. , Owing to the intriguing physical/chemical properties with rich coordination modes, MOFs have attracted increasing attention in catalysis, gas adsorption, energy storage, drug release, biosensing, fluorescence sensing, , etc. Especially, the ultrahigh porosity and large specific surface area of MOFs facilitate the efficient transport of the analytes, affording the promising electrochemical glucose sensors. − MOFs based on benzodicarboxylic acid (BDC) and 1,3,5-benzenetricarboxylic acid (BTC) have been attempted in electrochemical sensing. , However, Ni-BDC is restricted by a high detection limit and slow reaction kinetics, while Cu-BTC shows a narrow detection range.…”