Cobalt(II)-ion-exchanged Zn-bio-MOF-1 derived CoS/ZnS composites modified electrochemical sensor for chloroneb detection by differential pulse voltammetry

Nano-interface enhanced electrochemical sensing of hazardous organochlorine pesticides and prospects with ZnO based nanomaterials

Detection and analysis of organochlorine pesticides (OCP) residue is getting significant research importance because of their extensive use despite their hazardous effects on the health of people and the ecosystem. Despite the implementation of regulations and bans to safeguard human health and the environment, reports frequently reveal the continued use of these harmful chemicals in quantities exceeding the recommended limits set by regulatory boards. Data on the use of OCP from India, the most populous country, and African countries is not very encouraging. Conventional methods used for pesticide identification rely on high-cost and bulky instruments, which are also time-consuming and resource-intensive. Therefore, a low-cost, simple, easy-to-handle, and portable pesticide detection device is the need of the hour to enhance the convenience of routine detection and analysis. Nanomaterial-based sensors, composed of metal oxides, polymers, metals, enzyme-functionalized nanostructures, and nanocomposites, hold significant potential for monitoring pesticides, even at extremely low levels, and offer a unique alternative to traditional detection methods. This study examines the potential health risks associated with OCP residues and commonly used analytical techniques for pesticide detection. It also thoroughly examines the latest developments in nanomaterial-based electrochemical sensors, specifically focusing on ZnO-based nanomaterials for OCP detection. Researchers have successfully experimented with ZnO nanomaterials for pesticide degradation, in addition to their use in detection. This review provides a summary of the detection limits, linear ranges, and various fabrication methods of these developed sensors. It also addresses the practicality issues and detection strategies, thereby providing a comprehensive overview of the state of the art in OCP detection using nanomaterials. Furthermore, this review provides insights on potential future perspectives in the area from the authors' standpoint.

Development of an electrochemical sensor based on Ni-Bio-MOF and a molecular imprinted polymer for determination of diclofenac: electrochemical and DFT investigations

In this work, a metal-organic nickel framework (Ni-MOF) modified with a biological ligand (asparagine) (Ni-Bio-MOF) was synthesized by a hydrothermal method. Asparagine is believed to create defects on the surface of the MOF, thereby increasing its electrocatalytic activity. Then, a Diclofenac (DCF) polymer imprinted with l-methionine (PL-Met) was electrodeposited on a carbon paste electrode (CPE)/Ni-Bio-MOF and used as a new electrochemical sensor for highly selective and sensitive detection of DCF in biological and pharmaceutical samples. The Ni-Bio-MOF/MIP-PL-Met nanocomposite was characterized using the following techniques: FT-IR, FE-SEM, TEM, HR-TEM, XRD, XPS, and EDX. The electrochemical properties and performance of the sensor for the electrooxidation of DCF were assessed using CV, DPV, and EIS techniques. The electrochemical behavior of CPE/Ni-Bio-MOF/MIP-PL-Met and non-imprinted polymer (NIP) with an imprinting factor of 6.64 was investigated, and the influencing parameters in DCF measurement were optimized by cyclic voltammetry (CV). This modified sensor showed three dynamic ranges at 1.0-500.0 pM, 1.0-1000.0 nM, and 1.0-1000.0 μM of DCF with a limited detection (LOD) of 0.17 pM, sensitivity of 2015.5 μA μM-1 cm-2, relative standard deviation (RSD) of 3.3%, and reproducibility of 96.2%. Real samples of healthy human blood serum and DCF tablets were used to evaluate the practical application of the CPE/Ni-Bio-MOF/MIP-PL-Met electrochemical sensor. This method is simple, low-cost, with good limited detection, high sensitivity, and selectivity. The interactions of PL-Met with DCF were studied at the B3LYP/6-311++G(d,p) level of theory in both gaseous and aqueous phases. Additionally, the computational methodology investigated the thermodynamic stability of the proposed configurations and the role of hydrogen bonds in this system.

Application of nanomaterials in the detection of pesticide residues in spices

With the development of global trade and the improvement of consumer safety awareness, the problem of pesticide residues in spices has received considerable attention. At the same time, with the advancement of nanotechnology, nanomaterials have shown great potential in pesticide residue detection. Given the wide variety of spices and their complex matrices, there has been a lack of a comprehensive review on the application of nanomaterials in pesticide residue detection in spices until now. In this study, the advancements in research on newly developed nanomaterials were examined for the detection of pesticide residues in spices over the last 10 years, focusing on the applications of carbon nanotubes, graphene and its derivatives, metal nanoparticles, metal-organic frameworks, molecularly imprinted polymers, and quantum dots. Additionally, this study also explores the advantages and challenges of different nanomaterials' applications and predicts their development trends, aiming to provide a reference for future research.

State-of-the-Art, Insights, and Perspectives for MOFs-Nanocomposites and MOF-Derived (Nano)Materials

Composite structures created from metal‒organic framework (MOF) matrices are reviewed in this work. Depending on the nature of the second component apart from the MOF platform, several synergistic properties may arise; at the same time, the initial features of the single constituent materials are usually maintained, and individual shortcomings are mitigated. Currently, timely energy and environmental challenges necessitate the quest for more advanced materials and technologies. Significant developments in MOF-nanocomposites have enabled their application across a wide range of modern and traditional fields. This review demonstrates in an exhaustive and critical way a broad range of MOF-based nanocomposites, namely, MOF/perovskite nanoparticles (NPs), MOF/metal (non-iron) oxide NPs, MOF/Fe3O4 NPs, MOF/metal chalcogenide NPs, MOF/metal NPs, and MOF/carbon-based materials, as well as nanocomposites of MOFs with other semiconductor NPs. Key points related to the synthesis, characterization, and applications of these materials are provided. Depending on their configuration, the composites under discussion can be applied in domains such as photoelectrochemical sensing, antibiotic/dye degradation, optoelectronics, photovoltaics, catalysis, solar cells, supercapacitors, batteries, water remediation, and drug loading. Sometimes, MOFs can undergo certain processes (e.g. pyrolysis) and act as precursors for composite materials with appealing characteristics. Therefore, a special section in the manuscript is devoted to MOF-derived NP composites. Toward the end of the text, we conclude while also describing the challenges and possibilities for further investigations in the umbrella of material categories analyzed herein. Despite the progress achieved, key questions remain to be answered regarding the relationships among the morphology, properties, and polyvalent activity of these materials. The present work aims to shed light on most of their aspects and innovative prospects, facilitating a deeper comprehension of the underlying phenomena, functionality, and mechanistic insights governing their behavior.

Simple fluorochromic detection of chromium with ascorbic acid functionalized luminescent Bio-MOF-1

The bioaccumulation of various heavy metals in the environment and agriculture is posing serious hazards to human health. Hexavalent chromium is one of the most encountered heavy metal pollutants. The routine monitoring of Cr(VI) via simple methods assumes great analytical significance in sectors like environmental safety, food quality, etc. This study reports a novel biocompatible and luminescent metal-organic framework (ascorbic acid functionalized Bio-MOF-1) based "Turn-on" nanoprobe for rapid and sensitive optical detection of Cr(VI). Bio-MOF-1 has been synthesized, functionalized with ascorbic acid (AA), and then comprehensively characterized for its key material properties. The presence of Cr(VI) results in the photoluminescence recovery of Bio-MOF-1/AA. Using the above approach, Cr(VI) is detected over a wide concentration range of 0.02 to 20 ng mL-1, with the limit of detection being 0.01 ng mL-1. The nanoprobe is capable of detecting Cr(VI) in real water as well as in some spiked food samples. Hence, the ascorbic acid functionalized Bio-MOF-1 nanoprobe is established as a potential on-field detection tool for Cr(VI).

Trajectory in biological metal-organic frameworks: Biosensing and sustainable strategies-perspectives and challenges

The ligand attribute of biomolecules to form coordination bonds with metal ions led to the discovery of a novel class of materials called biomolecule-associated metal-organic frameworks (Bio-MOFs). These biomolecules coordinate in multiple ways and provide versatile applications. Far-spread bio-ligands include nucleobases, amino acids, peptides, cyclodextrins, saccharides, porphyrins/metalloporphyrin, proteins, etc. Low-toxicity, self-assembly, stability, designable and selectable porous size, the existence of rigid and flexible forms, bio-compatibility, and synergistic interactions between metal ions have led Bio-MOFs to be commercialized in industries such as sensors, food, pharma, and eco-sensing. The rapid growth and commercialization are stunted by absolute bio-compatibility issues, bulk morphology that makes it rigid to alter shape/porosity, longer reaction times, and inadequate research. This review elucidates the structural vitality, biocompatibility issues, and vital sensing applications, including challenges for incorporating bio-ligands into MOF. Critical innovations in Bio-MOFs' applicative spectrum, including sustainable food packaging, biosensing, insulin and phosphoprotein detection, gas sensing, CO2 capture, pesticide carriers, toxicant adsorptions, etc., have been elucidated. Emphasis is placed on biosensing and biomedical applications with biomimetic catalysis and sensitive sensor designing.

MIL-88B(Fe)-NH2: an amine-functionalized metal-organic framework for application in a sensitive electrochemical sensor for Cd2+, Pb2+, and Cu2+ ion detection

We propose here an electrochemical platform for multi-heavy metal ion detection in water based on MIL-88B(Fe)-NH₂, an amine-functioned metal-organic framework (MOF) for modifying the surface of a glassy carbon electrode (GCE). Herein, MIL-88B(Fe)-NH₂ with abundant functionalized amine groups can play the role of capture sites for the enrichment of metal ions before electrochemical oxidation sensing. MIL-88B(Fe)-NH₂ was synthesized under optimized conditions through a solvothermal method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. MIL-88B(Fe)-NH₂ was then drop-casted on GCE to electrochemically determine the Cd²⁺, Pb²⁺ and Cu²⁺ ion concentrations by differential pulse voltammetry (DPV). The electrochemical sensor exhibits excellent electrochemical performance toward Cd²⁺, Pb²⁺ and Cu²⁺ ions in the large linear ranges of 0.025-1.000 μM, 0.3-10.0 μM and 0.6-10.0 μM with limits of detection that are 2.0 × 10^-10 M, 1.92 × 10^-7 M and 3.81 × 10^-7 M, respectively. The fabricated sensor also shows high reliability and good selectivity. This MIL-88B(Fe)-NH₂ application strategy is promising for the evaluation of various heavy metal ions in water.

Metal-organic frameworks (MOFs) based luminescent and electrochemical sensors for food contaminant detection

With the increasing population, food toxicity has become a prevalent concern due to the growing contaminants of food products. Therefore, the need for new materials for toxicant detection and food quality monitoring will always be in demand. Metal-organic frameworks (MOFs) based on luminescence and electrochemical sensors with tunable porosity and active surface area are promising materials for food contaminants monitoring. This review summarizes and studies the most recent progress on MOF sensors for detecting food contaminants such as pesticides, antibiotics, toxins, biomolecules, and ionic species. First, with the introduction of MOFs, food contaminants and materials for toxicants detection are discussed. Then the insights into the MOFs as emerging materials for sensing applications with luminescent and electrochemical properties, signal changes, and sensing mechanisms are discussed. Next, recent advances in luminescent and electrochemical MOFs food sensors and their sensitivity, selectivity, and capacities for common food toxicants are summarized. Further, the challenges and outlooks are discussed for providing a new pathway for MOF food contaminant detection tools. Overall, a timely source of information on advanced MOF materials provides materials for next-generation food sensors.

Integration of Metallic Nanomaterials and Recognition Elements for the Specifically Monitoring of Pesticides in Electrochemical Sensing

Although all countries have been controlling the excessive use of pesticides, incidents of pesticide residues still existed. Electrochemical biosensors are extensively applied detection techniques to monitor pesticides with the help of different types of biorecognition components mainly including, antibodies, aptamers, enzymes (i.e., acetylcholinesterase, organophosphorus hydrolase, etc.), and synthetic molecularly imprinted polymers. Besides, the electrode materials mainly affected the sensitivity of electrochemical biosensors. Metallic nanomaterials with various structures and excellent electrical conductivity were desirable choice to construct electrochemical platforms to achieve the detection with high sensitivity and good specificity toward the target. This work reviewed the developed metallic materials including monometallic nanoparticles, bimetallic nanomaterials, metal atoms, metal oxides, metal molybdates, metal-organic frameworks, MXene, etc. Integration of recognition elements endowed the electrode materials with higher specificity toward the target pesticide. Besides, future challenges of metallic nanomaterials-based electrochemical biosensors for the detection of pesticides are also discussed and described.

Recent Advances in Nanoparticle-Based Optical Sensors for Detection of Pesticide Residues in Soil

The excessive and unreasonable use of pesticides has adversely affected the environment and human health. The soil, one of the most critical natural resources supporting human survival and development, accumulates large amounts of pesticide residues. Compared to traditional spectrophotometry analytical methods, nanoparticle-based sensors stand out for their simplicity of operation as well as their high sensitivity and low detection limits. In this review, we focus primarily on the functions that various nanoparticles have and how they can be used to detect various pesticide residues in soil. A detailed discussion was conducted on the properties of nanoparticles, including their color changeability, Raman enhancement, fluorescence enhancement and quenching, and catalysis. We have also systematically reviewed the methodology for detecting insecticides, herbicides, and fungicides in soil by using nanoparticles.

Metal-Organic Frameworks and Their Composites for Environmental Applications

From the point of view of the ecological environment, contaminants such as heavy metal ions or toxic gases have caused harmful impacts on the environment and human health, and overcoming these adverse effects remains a serious and important task. Very recent, highly crystalline porous metal-organic frameworks (MOFs), with tailorable chemistry and excellent chemical stability, have shown promising properties in the field of removing various hazardous pollutants. This review concentrates on the recent progress of MOFs and MOF-based materials and their exploit in environmental applications, mainly including water treatment and gas storage and separation. Finally, challenges and trends of MOFs and MOF-based materials for future developments are discussed and explored.