Manganese Metal–Organic Framework: Chemical Stability, Photoluminescence Studies, and Biosensing Application

A novel test device and quantitative colorimetric method for the detection of human chorionic gonadotropin (hCG) based on Au@Zn-salen MOF for POCT applications

The human chorionic gonadotropin (hCG) hormone is a biomarker that can predict tumors and early pregnancy; however, it is challenging to develop sensitive qualitative-quantitative procedures that are also effective, inventive, and unique. In this study, we used a novel easy in situ reaction of an organic nano-linker with Zn(NO₃)₂·6H₂O and HAuCl₄·3H₂O to produce a gold-zinc-salen metal-organic framework composite known as Au-Zn-Sln-MOF. A wide variety of micro-analytical instruments and spectroscopic techniques were used in order to characterize the newly synthesized Au-Zn-Sln-MOF composite. Disclosure is provided for a novel swab test instrument and a straightforward colorimetric approach for detecting hCG hormone based on an Au-Zn-Sln-MOF composite. Both of these methods are easy. In order to validate a natural enzyme-free immunoassay, an Au-Zn-Sln-MOF composite was utilized in the role of an enzyme; a woman can use this gadget to determine whether or not she is pregnant in the early stages of the pregnancy or whether or not her hCG levels are excessively high, which is a symptom that she may have a tumor. This cotton swab test device is compatible with testing of various biological fluids, such as serum, plasma, or urine, and it can be easily transferred to the market to commercialize it as a costless kit, which will be 20-30% cheaper than what is available on the market. Additionally, it can be used easily at home and for near-patient testing (applications of point-of-care testing (POCT)).

Prostate-Specific Antigen Monitoring Using Nano Zinc(II) Metal-Organic Framework-Based Optical Biosensor

BACKGROUND

The prostate-specific antigen (PSA) is an important cancer biomarker that is commonly utilized in the diagnosis of prostate cancer. The development of a PSA determination technique that is rapid, simple, and inexpensive, in addition to highly accurate, sensitive, and selective, remains a formidable obstacle.

METHODS

In this study, we developed a practical biosensor based on Zn(II) metal-organic framework nanoparticles (Zn-MOFs-NPs). Many spectroscopic and microanalytical tools are used to determine the structure, morphology, and physicochemical properties of the prepared MOF.

RESULTS

According to the results, Zn-MOFs-NPs are sensitive to PSA, selective to an extremely greater extent, and stable in terms of chemical composition. Furthermore, the Zn-MOFs-NPs did not exhibit any interferences from other common analytes that might cause interference. The detection limit for PSA was calculated and was 0.145 fg/mL throughout a wide linear concentration range (0.1 fg/mL-20 pg/mL).

CONCLUSIONS

Zn-MOFs-NPs were successfully used as a growing biosensor for the monitoring and measurement of PSA in biological real samples.

Nanomaterials and metal-organic frameworks for biosensing applications of mutations of the emerging viruses

The world today lives in a state of terrible fear due to the mutation of the emerging COVID-19. With the continuation of this pandemic, there is an urgent need for fast, accurate testing devices to detect the emerging SARS-CoV-2 pandemic in terms of biosensors and point-of-care testing. Besides, the urgent development in personal defense tools, anti-viral surfaces and wearables, and smartphones open the door for simplifying the self-diagnosis process everywhere. This review introduces a quick COVID-19 overview: definition, transmission, pathophysiology, the identification and diagnosis, mutation and transformation, and the global situation. It also focuses on an overview of the rapidly advanced technologies based on nanomaterials and MOFs for biosensing, diagnosing, and viral control of the SARS-CoV-2 pandemic. Finally, highlight the latest technologies, applications, existing achievements, and preventive diagnostic strategies to control this epidemic and combat the emerging coronavirus. This humble effort aims to provide a helpful survey that can be used to develop a creative solution and to lay down the future vision of diagnosis against COVID-19.

Pyrroloquinoline Based Styryl Dyes Doped PMMA, PS, and PS/TiO2 Polymer for Fluorescent Applications

This article presents two highly fluorescent donor-π-acceptor (D-π-A) moieties containing an electron-donating carbazole and phenothiazine donors fused with electron-withdrawing pyrrolo-quinoline acceptor dyes, PQC and PQPT. We also discussed the polymerization and film-forming process of dye PQC and PQPT doped in poly (methyl methacrylate) (PMMA) and polystyrene (PS) polymer to find their optical applications in polymer-based technology. We investigated the fluorescent properties of dyes PQC and PQPT from 0.01 to 1 wt% in poly(methyl methacrylate) (PMMA). We also investigated the changes in the spectrum shape and shift in wavelength with changes in poly(methyl methacrylate) (PMMA), polystyrene (PS), and TiO₂ doped in polystyrene (PS/TiO₂). The analysis of surface morphology of prepared polymer samples was done with the help of a scanning electron microscope. The thermal and photostability of synthesized dyes in poly (methyl methacrylate) (PMMA), polystyrene (PS), and TiO₂ doped in polystyrene (PS/TiO₂) were investigated to get detailed information owing to the application of fluorescent polymers in the field of optoelectronic, nanohybrid coatings in solar concentrators, etc.

Metal-Organic Frameworks-Based Sensors for Food Safety

Food contains a variety of poisonous and harmful substances that have an impact on human health. Therefore, food safety is a worldwide public concern. Food detection approaches must ensure the safety of food at every step of the food supply chain by monitoring and evaluating all hazards from every single step of food production. Therefore, early detection and determination of trace-level contaminants in food are one of the most crucial measures for ensuring food safety and safeguarding consumers' health. In recent years, various methods have been introduced for food safety analysis, including classical methods and biomolecules-based sensing methods. However, most of these methods are laboratory-dependent, time-consuming, costly, and require well-trained technicians. To overcome such problems, developing rapid, simple, accurate, low-cost, and portable food sensing techniques is essential. Metal-organic frameworks (MOFs), a type of porous materials that present high porosity, abundant functional groups, and tunable physical and chemical properties, demonstrates promise in large-number applications. In this regard, MOF-based sensing techniques provide a novel approach in rapid and efficient sensing of pathogenic bacteria, heavy metals, food illegal additives, toxins, persistent organic pollutants (POPs), veterinary drugs, and pesticide residues. This review focused on the rapid screening of MOF-based sensors for food safety analysis. Challenges and future perspectives of MOF-based sensors were discussed. MOF-based sensing techniques would be useful tools for food safety evaluation owing to their portability, affordability, reliability, sensibility, and stability. The present review focused on research published up to 7 years ago. We believe that this work will help readers understand the effects of food hazard exposure, the effects on humans, and the use of MOFs in the detection and sensing of food hazards.

Selective and Fast Detection of Fluoride-Contaminated Water Based on a Novel Salen-Co-MOF Chemosensor

The development of selective and fast optical sensitive chemosensors for the detection and recognition of different cations and anions in a domain is still a challenge in biological, industrial, and environmental fields. Herein, we report a novel approach for the detection and determination of fluoride ion (F-) sensing based on a salen-cobalt metal-organic framework (Co(II)-MOF). By a simple method, the Co(II)-MOF was synthesized and characterized using several tools to elucidate the structure and morphology. The photoluminescence (PL) spectrum of the Co(II)-MOF (100.0 nM/L) was examined versus different ionic species like F-, Br-, Cl-, I-, SO4 2-, and NO3 - and some cationic species like Mg2+, Ca2+, Na+, and K+. In the case of F- ions, the PL intensity of the Co(II)-MOF was scientifically enhanced with a remarkable red shift. With the increase of F- concentration, the Co(II)-MOF PL emission spectrum was also professionally enhanced. The limit of detection (LOD) for the Co(II)-MOF chemosensor was 0.24 μg/L, while the limit of quantification (LOQ) was 0.72 μg/L. Moreover, a comparison of the Co(II)-MOF optical approach with other published reports was studied, and the mechanism of interaction was also investigated. Additionally, the applicability of the current Co(II)-MOF approach in different real water samples, such as tap water, drinking water, Nile River water, and wastewater, was extended. This easy-to-use future sensor provides reliable detection of F- in everyday applications for nonexpert users, especially in remote rural areas.

A novel nano-lanthanum complex: synthesis, characterization and application as a macrofuran chemosensor in pharmaceutical, biological and environmental samples

Macrofuran is widely used as an antibiotic for the treatment of urinary tract infections. Nevertheless, it is prohibited due to toxicity and environmental concerns. The development of a fast, simple, and cost-effective approach for the determination of macrofuran antibiotic (MFA) is still a challenge. Herein, we report a chemosensor based on a nano-lanthanum complex derived from phenylenediamine. The physicochemical properties and structure of the prepared complex were confirmed using different spectroscopic tools such as X-ray diffraction (XRD), scanning electron microscopy equipped with EDX, elemental analysis, Fourier transform-infrared (FT-IR) spectroscopy, UV-vis spectroscopy, mass spectroscopy and photoluminescence (PL). The nano-lanthanum complex was found to be chemically stable, highly sensitive and selective to MFA, without interference from other common antibiotics. The limit of detection for MFA was 0.025 ng mL-1, over a linear concentration range of 0.02-30.0 ng mL-1, with a correlation coefficient of 0.994. The nano-lanthanum complex can be used successfully as a promising chemosensor for MFA determination in pharmaceutical formulation and different biological samples (whole blood-serum-plasma). In addition, this approach will protect human beings from the environmental hazards of antibiotics through the detection of the low limit of MFA. Meanwhile, the mechanism of interaction between the nano-lanthanum complex and MFA was studied and investigated.