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

Nano-engineered eco-friendly materials for food safety: Chemistry, design and sustainability

The sensitive detection, extraction and analysis of organic compounds such as pharmaceuticals as contaminants in food is very crucial. For this purpose, the effective utilization of sustainable nanomaterials is a promising strategy that combines the benefits of sustainability principles with nanotechnology to ensure the quality and safety of food products. Eco-friendly nanomaterials are distinguished by their exceptional properties, including sustainable synthesis, minimized ecological impact, and production from renewable or waste resources (e.g., cellulose, chitosan, lignin). This review paper elucidates the latest advancements and emerging trends in the development of eco-friendly nanomaterial-based sensor and extraction platforms for the efficient detection and removal of antibiotics as organic contaminants from food samples. The introduction section briefly outlines the significance and benefits of nanomaterials in the construction of sensor platforms. Subsequently, green methodologies for the synthesis of nanomaterials are discussed. Then, the paper progresses with various applications of eco-friendly nanomaterial-based sensor platforms and separation systems towards antibiotic contaminants in food samples. The final section offers conclusions and future perspectives.

Recent Advances in Metal-Organic Framework-Based Anticancer Hydrogels

Cancer is the second leading cause of death globally and the estimated number of new cancer cases and deaths will be ∼30.2 million and 16.3 million, respectively, by 2040. These numbers cause massive, physical, emotional, and financial burdens to society and the healthcare system that lead to further research for a better and more effective therapeutic strategy to manage cancer. Metal-organic frameworks (MOFs) are promising alternative approaches for efficient drug delivery and cancer theranostics owing to their unique properties and the direct transportation of drugs into cells followed by controlled release, but they suffer from certain limitations like rigidity, poor dispersibility, fragility, aggregation probability, and limited surface accessibility. Therefore, MOFs were conjugated with polymeric hydrogels, leading to the formation of MOF-based hydrogels with abundant absorption sites, flexibility, and excellent mechanical properties. This review briefly describes the different strategies used for the synthesis and characterization of MOF-based hydrogels. Further, we place special emphasis on the recent advances in MOF-based hydrogels used to manage different cancers. Finally, we conclude the challenges and future perspectives of MOF-based hydrogels. We believe that this review will help researchers to develop more MOF-based hydrogels with augmented anticancer effects, enabling the effective management of cancer even without adverse effects.

Guanine-based spin valve with spin rectification effect for an artificial memory element

Non-volatile electronic memory elements are very attractive for applications, not only for information storage but also in logic circuits, sensing devices and neuromorphic computing. Here, a ferroelectric film of guanine nucleobase is used in a resistive memory junction sandwiched between two different ferromagnetic films of Co and CoCr alloys. The magnetic films have an in-plane easy axis of magnetization and different coercive fields whereas the guanine film ensures a very long spin transport length, at 100 K. The non-volatile resistance states of the multiferroic spintronic junction with two-terminals are manipulated by a combined action of small external magnetic and electric fields. Thus, the magnetic field controls the relative orientation of the magnetization of the metallic ferromagnetic electrodes, that leads to different magnetoresistance states. The orientation and the magnitude of the electric field controls the orientation of the polarization of the guanine ferroelectric barrier, that leads to different electroresistance states, respectively. Moreover, we have observed a strong interfacial coupling of the two parameters. Consequently, positive and negative magnetoresistance hysteresis loops corresponding to spin rectification effects and non-hysteretic (erased) resistive states are manipulated with the electric field by switching the orientation of the electrical polarization of the organic ferroelectric.

Wearable Aptasensors

This Perspective explores the revolutionary advances in wearable aptasensor (WA) technology, which combines wearable devices and aptamer-based detection systems for personalized, real-time health monitoring. The devices leverage the specificity and sensitivity of aptamers to target specific molecules, offering broad applications from continuous glucose tracking to early diagnosis of diseases. The integration of data analytics and artificial intelligence (AI) allows early risk prediction and guides preventive health measures. While challenges in miniaturization, power efficiency, and data security persist, these devices hold significant potential to democratize healthcare and reshape patient-doctor interactions.

Advances in metal-organic frameworks for optically selective alkaline phosphatase activity monitoring: a perspective

The study of Metal-Organic Frameworks (MOFs) has gained significant momentum due to their remarkable properties, including adjustable pore sizes, extensive surface area, and customizable compositions, which have urged scientists to investigate their applicability in pertinent societal issues such as water absorption, environmental remediation, and sensor technology. MOFs have the ability to transport and detect specific biomolecules, including proteins. One such biomolecule is alkaline phosphatase (ALP) that can be influenced by various diseases and can lead to severe consequences when its regulation is disrupted. The porous nature of MOFs and their tunable nature allows them to selectively adsorb, interact directly or indirectly with ALP. This ultimately influences the electronic and optical properties of the MOF, leading to measurable changes. Early detection and continuous monitoring of ALP play a crucial role in the use of an effective treatment, and recent studies have shown that MOFs are effective in detecting alkaline phosphatases. This manuscript offers a thorough examination of the potential biomedical applications of MOFs for monitoring alkaline phosphatase and envisions possible future trends in this field.

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.