Mini review about metal organic framework (MOF)-based wearable sensors: Challenges and prospects

Nanostructured Transition Metal Oxides on Carbon Fibers for Supercapacitor and Li-Ion Battery Electrodes: An Overview

Nowadays, owing to the new technological and industrial requirements for equipment, such as flexibility or multifunctionally, the development of all-solid-state supercapacitors and Li-ion batteries has become a goal for researchers. For these purposes, the composite material approach has been widely proposed due to the promising features of woven carbon fiber as a substrate material for this type of material. Carbon fiber displays excellent mechanical properties, flexibility, and high electrical conductivity, allowing it to act as a substrate and a collector at the same time. However, carbon fiber's energy-storage capability is limited. Several coatings have been proposed for this, with nanostructured transition metal oxides being one of the most popular due to their high theoretical capacity and surface area. In this overview, the main techniques used to achieve these coatings-such as solvothermal synthesis, MOF-derived obtention, and electrochemical deposition-are summarized, as well as the main strategies for alleviating the low electrical conductivity of transition metal oxides, which is the main drawback of these materials.

Development of an aptasensor for highly sensitive detection of cardiac troponin I using cobalt-nickel metal-organic framework (CoNi-MOF)

Objective and rationale

This study aimed to develop a highly sensitive and selective single-stranded DNA (ssDNA) aptamer targeting cardiac troponin I (cTnI), a crucial biomarker for acute myocardial infarction (AMI). The objective was to fabricate a novel aptamer electrochemical sensor using a composite material of cobalt-nickel metal-organic framework (CoNi-MOF) on screen-printed carbon electrodes (SPCE), leveraging the composite's large surface area and excellent electrical conductivity alongside the aptamer's high affinity for cTnI.

Methods

The aptamer electrochemical sensor was fabricated using the CoNi-MOF composite on SPCE and characterized its properties. They conducted electrochemical measurements to assess the sensor's performance in detecting cTnI. The sensor's stability, reproducibility, and electro-catalytic activity were evaluated.

Results

The sensor demonstrated linear detection of cTnI over a concentration range of 5-75 pg/mL, with a low limit of detection (LOD) of 13.2 pM. Remarkable stability and reproducibility were observed in cTnI detection. The sensor exhibited exceptional electro-catalytic activity, enabling accurate quantification of cTnI levels in various solutions.

Conclusions

This research presents a significant advancement towards the development of reliable, cost-effective, and easily deployable cTnI sensors for clinical applications. The sensor's versatility in detecting cTnI across different concentration ranges highlights its potential utility in diverse clinical settings, particularly for early detection and monitoring of cardiac conditions.

Sensing platform for the highly sensitive detection of catechol based on composite coupling with conductive Ni3(HITP)2 and nanosilvers

Catechol, which has a high toxicity and low degradability, poses significant risks to both human health and the environment. Tracking of catechol residues is essential to protect human health and to assess the safety of the environment. We constructed sensing platforms to detect catechol based on the conductive metal-organic frameworks [Ni3(HITP)2] and their nanosilver composites. The reduction process of catechol at the Ni3(HITP)2/AgNP electrode is chemically irreversible as a result of the difference in compatibility of the oxidation stability and conductivity between the Ni3(HITP)2/AgNS and Ni3(HITP)2/AgNP electrodes. The electrochemical results show that the Ni3(HITP)2/AgNS electrode presents a lower detection limit of 0.053 μM and better sensitivity, reproducibility and repeatability than the Ni3(HITP)2/AgNP electrode. The kinetic mechanism of the catechol electrooxidation at the surface of the electrode is controlled by diffusion through a 2H+/2e- process. The transfer coefficient is the key factor used to illustrate this process. During the electrochemical conversion of phenol to ketone, more than half of ΔG is used to change the activation energy. We also studied the stability, anti-interference and reproducibility of these electrode systems.