Exploring the potential of SrTi0.7Fe0.3O3 perovskite/Chitosan nanosheets for the development of a label-free electrochemical sensing assay for determination of naproxen in human plasma samples.

Naproxen is a nonsteroidal anti-inflammatory drug used to treat nonrheumatic inflammation, migraine, and gout. Therefore, the determination of naproxen in pharmaceutical and biological samples is of particular importance. In the present work, SrTi0.7Fe0.3O3 perovskite/Chitosan nanosheets were used to modify the surface of a glassy carbon electrode (GCE) for highly sensitive determination of naproxen. To ensure the successful synthesis of the perovskite nanosheets, morphological studies including scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were carried out. The electrochemical investigations of naproxen on the modified surface of GCE were investigated and the limit of detection (LOD) and limit of quantification (LOQ) were acquired 0.50 and 1.67 µM, respectively. Additionally, the linear range (LR) of 1.99-130.84 µM was obtained for the oxidation of naproxen. The obtained results have been proved that the mentioned method is simple, sensitive, and specific with a short analysis time. The dominant analytical features of the designed sensor are possessing a low detection limit, excellent stability, repeatability, and high selectivity in the presence of naproxen. For investigation of the applicability of the designed assay in real sample analysis, human plasma samples have been examined and a recovery index was acquired 95%.

Ru-Ni nanoparticles electrodeposited on rGO/Ni foam as a binder-free, stable and high-performance anode catalyst for direct hydrazine fuel cell.

Bimetallic Ru-Ni nanoparticles was synthesized on the reduced graphene oxide decorated Ni foam (Ru-Ni/rGO/NF) by electroplating method to be utilized as the anode electrocatalyst for direct hydrazine-hydrogen peroxide fuel cells (DHzHPFCs). The synthesized electrocatalysts were characterized by X-ray diffraction, Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. The electrochemical properties of catalysts towards hydrazine oxidation reaction in an alkaline medium were evaluated by cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy. In the case of Ru1-Ni3/rGO/NF electrocatalyst, Ru1-Ni3 provided active sites due to low activation energy (22.24 kJ mol-1) for hydrazine oxidation reaction and reduced graphene oxide facilitated charge transfer by increasing electroactive surface area (EASA = 677.5 cm2) with the small charge transfer resistance (0.1 Ω cm2). The CV curves showed that hydrazine oxidation on the synthesized electrocatalysts was a first-order reaction in low concentrations of N2H4 and the number of exchanged electrons was 3.0. In the single cell of the of direct hydrazine-hydrogen peroxide fuel cell, the maximum power density value of Ru1-Ni3/rGO/NF electrocatalyst was 206 mW cm-2 and the open circuit voltage was 1.73 V at 55 °C. These results proved that the Ru1-Ni3/rGO/NF is a promising candidate for using as the free-binder anode electrocatalyst in the future application of direct hydrazine-hydrogen peroxide fuel cells due to its excellent structural stability, ease of synthesis, low cost, and high catalytic performance.

Self-assembled monolayer-assisted label-free electrochemical genosensor for specific point-of-care determination of Haemophilus influenzae.

For sensitive detection of the L-fuculokinase genome related to the Haemophilus influenzae (H. influenzae), this research work demonstrates the label-free electrochemical-based oligonucleotide genosensing assay relying on the performing hybridization process. To enhance the electrochemical responses, multiple electrochemical modifier-tagged agents were effectively utilized. For attaining this goal, NiCr-layered double hydroxide (NiCr LDH) has been synthesized and combined with biochar (BC) to create an efficient electrochemical signal amplifier that has been immobilized on the surface of the bare Au electrode. Low detection and quantification limits (LOD and LOQ) associated with the designed genosensing bio-platform to detect L-fuculokinase have been achieved to 6.14 fM and 11 fM, respectively. Moreover, the wide linear range of 0.1 to 1000 pM demonstrates the capability of the designed platform. Investigated were the 1-, 2-, and 3-base mismatched sequences, and the negative control samples clarified the high selectivity and better performance of the engineered assay. The values of 96.6-104% and 2.3-3.4% have been obtained for the recoveries and RSDs, respectively. Furthermore, the repeatability and reproducibility of the associated bio-assay have been studied. Consequently, the novel method is appropriate for rapidly and quantitatively detecting H. influenzae, and is considered a better candidate for advanced tests on biological samples such as urine samples.

An Ultrasensitive miRNA-Based Genosensor for Detection of MicroRNA 21 in Gastric Cancer Cells Based on Functional Signal Amplifier and Synthesized Perovskite-Graphene Oxide and AuNPs.

In the present research work, the state-of-art label-free electrochemical genosensing platform was developed based on the hybridization process in the presence of [Fe(CN)6]3-/4- as an efficient redox probe for sensitive recognition of the miRNA-21 in human gastric cell lines samples. To attain this aim, perovskite nanosheets were initially synthesized. Afterward, the obtained compound was combined with the graphene oxide resulting in an effective electrochemical modifier, which was dropped on the surface of the Au electrode. Then, AuNPs (Gold Nano Particles) have been electrochemically-immobilized on perovskite-graphene oxide/Au-modified electrode surface through the chronoamperometry (CA) technique. Finally, a self-assembling monolayer reaction of ss-capture RNA ensued by the thiol group at the end of the probe with AuNPs on the modified electrode surface. miRNA-21 has been cast on the Au electrode surface to apply the hybridization process. To find out the effectiveness of the synthesized modifier agent, the electrochemical behavior of the modified electrode has been analyzed through DPV (differential pulse voltammetry) and CV (cyclic voltammetry) techniques. The prepared biomarker-detection bioassay offers high sensitivity and specificity, good performance, and appropriate precision and accuracy for the highly-sensitive determination of miRNA-21. Different characterization methods have been used, such as XRD, Raman, EDS, and FE-SEM, for morphological characterization and investigation of particle size. Based on optimal conditions, the limit of detection and quantification have been acquired at 2.94 fM and 8.75 fM, respectively. Furthermore, it was possible to achieve a wide linear range which is between 10-14 and 10-7 for miRNA-21. Moreover, the selectivity of the proposed biosensing assay was investigated through its potential in the detection of one, two, and three-base mismatched sequences. Moreover, it was possible to investigate the repeatability and reproducibility of the related bio-assay. To evaluate the hybridization process, it is important that the planned biomarker detection bio-assay could be directly re-used and re-generated.

MOF-Based Mycotoxin Nanosensors for Food Quality and Safety Assessment through Electrochemical and Optical Methods.

Mycotoxins in food are hazardous for animal and human health, resulting in food waste and exacerbating the critical global food security situation. In addition, they affect commerce, particularly the incomes of rural farmers. The grave consequences of these contaminants require a comprehensive strategy for their elimination to preserve consumer safety and regulatory compliance. Therefore, developing a policy framework and control strategy for these contaminants is essential to improve food safety. In this context, sensing approaches based on metal-organic frameworks (MOF) offer a unique tool for the quick and effective detection of pathogenic microorganisms, heavy metals, prohibited food additives, persistent organic pollutants (POPs), toxins, veterinary medications, and pesticide residues. This review focuses on the rapid screening of MOF-based sensors to examine food safety by describing the main features and characteristics of MOF-based nanocomposites. In addition, the main prospects of MOF-based sensors are highlighted in this paper. MOF-based sensing approaches can be advantageous for assessing food safety owing to their mobility, affordability, dependability, sensitivity, and stability. We believe this report will assist readers in comprehending the impacts of food jeopardy exposure, the implications on health, and the usage of metal-organic frameworks for detecting and sensing nourishment risks.

Advances in layered double hydroxide based labels for signal amplification in ultrasensitive electrochemical and optical affinity biosensors of glucose.

Since the development of enzyme electrodes, the research area of glucose biosensing has seen outstanding progress and improvement. Numerous sensing platforms have been developed based on different immobilization techniques and improved electron transfer between the enzyme and electrode. Interestingly, these platforms have consistently used innovative nanostructures and nanocomposites. In recent years, layered double hydroxides (LDHs) have become key tools in the field of analytical chemistry owing to their outstanding features and benefits, such as facile synthesis, cost-effectiveness, substantial surface area, excellent catalytic performance, and biocompatibility. LDHs are often synthesized as nanomaterial composites or manufactured with specific three-dimensional structures. The purpose of this review is to illustrate the biosensing prospects of LDH-based glucose sensors and the need for improvement. First, various clinical and conventional approaches for glucose determination are discussed. The definitions, types, and various synthetic methodologies of LDHs are then explained. Subsequently, we discuss the various research studies regarding LDH-based electrochemical and optical assays, focusing on modified systems, improved electron transfers pathways (through developments in surface science), and different sensing designs based on nanomaterials. Finally, a summary of the current limitations and future challenges in glucose analysis is described, which may facilitate further development and applications.

MOF-based sensor platforms for rapid detection of pesticides to maintain food quality and safety.

Pesticides are primarily used in agriculture to increase crop yield because of their highly lucrative, stable structure and agricultural benefits such as eliminating fungi, plant diseases, pests and insects to regulate the growth of crops. Apart from their rebel design and agricultural benefits, pesticides have severe toxicity to a variety of other living organisms. Therefore, developing effective pesticide detection systems is an ongoing challenge. Multiple technologies that for the rapid, easy, sensitive, and selective detection of these neurotoxic compounds are in demand. This paper reviews the recent advances in sensing assays based on the metal-organic framework (MOF) structure for pesticide detection. We have reviewed state-of-the-art optical biosensors for in-place sensing that have the advantages of a simple protocol, simple manipulation, super sensitivity, wide linear range, and cost-effectiveness. These biosensors use chemiluminescence with a short sensing time and a highly sensitive luminescence sensor that enables real-time detection by easy smartphone pairing. For profitable platforms, the obstacles related to sample preparation and equipment cost can be overcome by employing electrochemical sensors. The intensity, impedance, and potential difference measurement techniques used in these biosensors allow for low detection limits and observable durations in water, agricultural, and food samples containing high levels of pesticides.

Electrochemical layered double hydroxide (LDH)-based biosensors for pesticides detection in food and environment samples: A review of status and prospects.

The need for food and agricultural resources is constantly rising, resulting in pesticide poisoning and environmental hazards. Diverse technologies collaborate to develop effective biosensors for detecting different pesticides, as it is difficult to achieve an efficient mechanism to detect pesticides. Novel solutions to reduce the cost and time for preparing samples in pesticide detection are being developed using new technologies. Moreover, methods like electrochemical techniques and fluorescence spectroscopy are now being improved to increase the sensitivity and make the operation more convenient. This article reviews the remarkable evolution in the structure of various Layered Double Hydroxides (LDHs), their various synthesis techniques, and their uses in various fields, especially in biological applications to detect pesticides in diverse contaminated samples. LDHs are layered materials with special characteristics favorable for pesticide detection. LDHs, have recently aroused increasing interest in research. We also discuss the latest advances made in the emergent strategies for improving the antimicrobial activity of LDHs.

Recent trends in layered double hydroxides based electrochemical and optical (bio)sensors for screening of emerging pharmaceutical compounds.

The rapid expansion of the human population has given rise to new environmental and biomedical concerns, contributing to different advancements in the pharmaceutical industry. In the field of analytical chemistry over the last few years, layered double hydroxides (LDHs) have drawn significant attention, owing to their extraordinary properties. Furthermore, the novel advancement of LDH-based optical and electrochemical platforms to detect different pharmaceutical materials has acquired substantial attention because of their outstanding specificity, actual-time controlling, and user-friendliness. This review aims to recapitulate advanced LDHs-based optical and electrochemical sensors and biosensors to identify and measure important pharmaceutical compounds, such as anti-depressant, anti-inflammatory, anti-viral, anti-bacterial, anti-cancer, and anti-fungal drugs. Additionally, fundamental parameters, namely interactions between sensor and analyte, design rationale, classification, selectivity, and specificity are considered. Finally, the development of high-efficiency techniques for optical and electrochemical sensors and biosensors is featured to deliver scientists and readers a complete toolbox to identify a broad scope of pharmaceutical substances. Our goals are: (i) to elucidate the characteristics and capabilities of available LDHs for the identification of pharmaceutical compounds; and (ii) to deliver instances of the feasible opportunities that the existing devices have for the developed sensing of pharmaceuticals regarding the protection of ecosystems and human health at the global level.

Lateral flow assays (LFA) for detection of pathogenic bacteria: A small point-of-care platform for diagnosis of human infectious diseases.

Up-to-date diagnostics is globally improved by point-of-care testing (POCT) analysis and bedside research works. Development in POCT analysis has been provided mostly by forward-looking engineering technology for biosensing and sensing assessments. Lately, lateral flow assays (LFAs) have attracted a lot of interest as a result of their noteworthy benefits including cost-effectiveness, better portability, being operator friendly and rapid detection. This technique has been employed broadly for monitoring diverse biomarkers linked to ultrasensitive detection of pathogenic bacteria, ecological monitoring, consumer protection, and infectious diseases. LFA analyses established on qualitative and optical outcomes have boosted the objectivity and data efficiency of the assessments. Therefore, developing novel methods with the capability of providing reliable and quantitative information regarding a target analyte in a model and preserving the qualities of LFAs is of great necessity. In this review, the main principles of LFAs, challenges, and prospects for more development in this field in sensing pathogenic bacteria have been summarized. Subsequently, visually-read LFAs improvement to further progressive platforms have been explored by considering the prospects of this very flexible method for ultrasensitive detection of pathogenic bacteria. In addition, novel labeling methodologies, electrochemical and optical transducers are described. Also, recent developments in these detection methods elements in combination with other considered approaches have been highlighted.

State of the art: Lateral flow assays toward the point-of-care foodborne pathogenic bacteria detection in food samples.

Diverse chemicals and some physical phenomena recently introduced in nanotechnology have enabled scientists to develop useful devices in the field of food sciences. Concerning such developments, detecting foodborne pathogenic bacteria is now an important issue. These kinds of bacteria species have demonstrated severe health effects after consuming foods and high mortality related to acute cases. The most leading path of intoxication and infection has been through food matrices. Hence, quick recognition of foodborne bacteria agents at low concentrations has been required in current diagnostics. Lateral flow assays (LFAs) are one of the urgent and prevalently applied quick recognition methods that have been settled for recognizing diverse types of analytes. Thus, the present review has stressed on latest developments in LFAs-based platforms to detect various foodborne pathogenic bacteria such as Salmonella, Listeria, Escherichia coli, Brucella, Shigella, Staphylococcus aureus, Clostridium botulinum, and Vibrio cholera. Proper prominence has been given on exactly how the labels, detection elements, or procedures have affected recent developments in the evaluation of diverse bacteria using LFAs. Additionally, the modifications in assays specificity and sensitivity consistent with applied food processing techniques have been discussed. Finally, a conclusion has been drawn for highlighting the main challenges confronted through this method and offered a view and insight of thoughts for its further development in the future.

Bimetallic Fe/Mn MOFs/MßCD/AuNPs stabilized on MWCNTs for developing a label-free DNA-based genosensing bio-assay applied in the determination of Salmonella typhimurium in milk samples.

Monitoring of pathogenic bacteria plays a vital role in precluding foodborne disease outbreaks. In this research work, a genosensor based on innovative label-free DNA was developed for the detection of Salmonella. typhimurium (S. typhimurium) in the milk samples. To realize this objective, bimetallic Fe/Mn MOF is synthesized and mixed with methyl-ß-cyclodextrin (MßCD) and AuNPs which are then stabilized on multi-walled carbon nanotubes (MWCNTs), and the obtained nanocomposite is immobilized on the Au electrode surface. Different characterization methods such as FE-SEM, TEM, EDS, FTIR, and XRD were used for investigating the particle size and morphological features. Electrochemical and impedimetric techniques were used for exploring the applicability of the fabricated genosensor. Under optimal circumstances, LOD and LOQ have acquired at 0.07 pM and 0.21 pM. Moreover, an extensive linear range of 1 pM-1 µM was resulted for ss-tDNA (single-stranded target DNA), R2 obtained 0.9991. The recoveries were obtained 95.6-104%. Great selectivity against one, two, and three-base mismatched sequences was also shown for fabricated biosensing assay. Furthermore, negative genosensing assay control for investigating selectivity was provided by the ss-tDNAs of Haemophilusinfluenzae and Shigella dysenteriae bacteria. Well-fabricated genosensing bio-assay represents better performance, great specificity, high sensitivity, increased active sites, and finally results in an increase in the electron transfer rate. It is to be noted that the organized genosensing bio-assay is capable of being re-used and re-generated in a straightforward manner to estimate the hybridization process.

A PCR-free genosensing platform for detection of Shigella dysenteriae in human plasma samples by porous and honeycomb-like biochar decorated with ultrathin flower-like MoS2 nanosheets incorporated with Au nanoparticles.

Shigella dysenteriae, a gram-negative bacterium, which results in the most infectious of bacterial shigellosis and dysenteries. In this study, an innovative gene detection platform based on label-free DNA sequences was developed to detect Shigella dysenteriae in human plasma samples. The porous and honeycomb-like structure of biochar (BC) was first synthesized through a pyrolysis process. Then, the produced biochar was effectively decorated with flower-like MoS2 nanosheets (MoS2/BC). The resulting nanocomposite was incorporated with Au nanoparticles (AuNPs) by applying chronoamperometry technique, and then the subsequent product including MoS2 nanosheets, biochar and AuNPs were immobilized on the Au electrode surface and used for modifier agent in electrochemical bio-assays. Structural and morphological study of the synthesized compounds were investigated using various characterization methods such as FE-SEM, TEM, EDS, FTIR, and XRD. Various electrochemical techniques including cyclic voltammetry (CV) and Differential pulse anodic stripping voltammetry (DPASV) have been used to investigate the applicability of the fabricated genosensing bio-assay. Under optimal conditions, LOD and LOQ were calculated 9.14 fM and 0.018 pM respectively. In addition, a linear range from 0.01 to 100 pM was obtained for single stranded-target DNA (ss-tDNA), with R2 of 0.9992. The recoveries ranged from 98.0 to 101.3%. The fabricated bio-detection assay demonstrated high selectivity for 1, 2, and 3 base mismatch sequences. In addition, a negative control of the gene detection platform which was performed to study selectivity was provided by ss-tDNA from Haemophilusinfluenzae, and Salmonella typhimurium. Moreover, it is important to mention that the organized bioassay is simply reusable and reproducible with the RSD% (relative standard deviation) ˂ 5 to next detection assays.

Recent advances in the highly sensitive determination of zearalenone residues in water and environmental resources with electrochemical biosensors.

Zearalenone (ZEN), a significant class of mycotoxin which is considered as a xenoestrogen, permits, similar to natural estrogens, it's binding to the receptors of estrogen resulting in various reproductive diseases especially, hormonal misbalance. ZEN has toxic effects on human and animal health as a result of its teratogenicity, carcinogenicity, mutagenicity, nephrotoxicity, genotoxicity, and immunotoxicity. To ensure water and environmental resources safety, precise, rapid, sensitive, and reliable analytical and conventional methods can be progressed for the determination of toxins such as ZEN. Different selective nanomaterial-based compounds are used in conjunction with different analytical detection approaches to achieve this goal. The current review demonstrates the state-of-the-art advances of nanomaterial-based electrochemical sensing assays including various sensing, apta-sensing and, immunosensing studies to the highly sensitive determination of various ZEN families. At first, a concise study of the occurrence, structure, toxicity, legislations, and distribution of ZEN in monitoring has been performed. Then, different conventional and clinical techniques and procedures to sensitive and selective sensing techniques have been reviewed and the efficient comparison of them has been thoroughly discussed. This study has also summarized the salient features and the requirements for applying various sensing and biosensing platforms and diverse immobilization techniques in ZEN detection. Finally, we have defined the performance of several electrochemical sensors applying diverse recognition elements couples with nanomaterials fabricated using various recognition elements coupled with nanomaterials (metal NPs, metal oxide nanoparticles (NPs), graphene, and CNT) the issues limiting development, and the forthcoming tasks in successful construction with the applied nanomaterials.

Emerging electrochemical sensing and biosensing approaches for detection of Fumonisins in food samples.

Fumonisins (FBs) can be found extensively in feedstuffs, foodstuffs, and crops. The consumption of the fumonisin-contaminated corn can result in esophageal cancer. In addition, the secondary metabolites of fungi termed mycotoxins may have some adverse effects on animals and humans such as estrogenicity, immunotoxicity, teratogenicity, mutagenicity, and carcinogenicity. Hence, developing sensitivity techniques for mycotoxins determination is of great importance. This paper reports the latest developments of nanomaterial-based electrochemical biosensing, apta-sensing, sensing, and immunosensing analyses to detect fumonisins. A concise study of the occurrence, legislations, toxicity, and distribution of FBs in levels monitoring was done. The techniques, different detection matrices, and approaches to highly selective and sensitive sensing methods were reviewed. The review also summarizes the salient features and the necessity of biosensing assessments in FBs detection, and diverse immobilization techniques. Furthermore, this review defined the performance of various electrochemical sensors using different detection elements couples with nanomaterials fabricated applying different detection elements coupled with nanomaterials (metal oxide nanoparticles (NPs), metal NPs, CNT, and graphene), the factors limiting progress, and the upcoming tasks in successful aptasensor fabrication with the functionalized nanomaterials.

Patulin and Trichothecene: characteristics, occurrence, toxic effects and detection capabilities via clinical, analytical and nanostructured electrochemical sensing/biosensing assays in foodstuffs.

Patulin and Trichothecene as the main groups of mycotoxins in significant quantities can cause health risks from allergic reactions to death on both humans and animals. Accordingly, rapid and highly sensitive determination of these toxics agents is of great importance. This review starts with a comprehensive outlook regarding the characteristics, occurrence and toxic effects of Patulin and Trichothecene. In the following, numerous clinical and analytical approaches have been extensively discussed. The main emphasis of this review is placed on the utilization of novel nanomaterial based electrochemical sensing/biosensing tools for highly sensitive determination of Patulin and Trichothecene. Furthermore, a detailed and comprehensive comparison has been performed between clinical, analytical and sensing methods. Subsequently, the nanomaterial based electrochemical sensing platforms have been approved as reliable tools for on-site analysis of Patulin and Trichothecene in food processing and manufacturing industries. Different nanomaterials in improving the performance of detecting assays were investigated and have various benefits toward clinical and analytical methods. This paper would address the limitations in the current developments as well as the future challenges involved in the successful construction of sensing approaches with the functionalized nanomaterials and also allow exploring into core-research works regarding this area.[Formula: see text].

SU8/glass microchip capillary electrophoresis integrated with Pt electrodes for separation and simultaneous detection of phenylephrine and acetaminophen.

Introduction: A new microfluidic-based method with electrochemical detection was developed for the simultaneous quantification of acetaminophen (AP) and phenylephrine (PHE) pharmaceuticals in the human blood and pharmaceuticals (e.g. tablet and drop). Methods: The separation was achieved on a SU8/glass microchip with a 100 µm Pt working electrode that was positioned out of the channel and 2-(N-morpholino) ethanesulfonic acid was used as a running buffer (pH 7, 10 mM). Home designed modulated high voltage power supply and dual time switcher was used for controlling the injection and separation of the analytes in the unpinched injection mode. Results: The injection was carried out using +750 V for 7 seconds, and the separation and detection voltages were set at +1000 V and +0.9 V, respectively. Critical parameters such as detection potential, buffer concentration, injection, and separation voltage were studied in terms of their effects on the resolution, peak height, and migration times. For each analyte, the correlation coefficients were over 0.99 (n = 6). The developed microchip was able to detect AP and phenylephrine simultaneously with the limit of detection of 7.9 and 5.2 (µg/mL) respectively for PHE and AP and excellent linear range of 10-200 (µg/mL). The recovery of the drugs ranged from 96% to 103%, while the repeatability of the method through inter- and intra-day was lower than 7%. Conclusion: The developed method offers several advantages, including easy sample pretreatment process, simplicity, very fast analysis compared to other typical chromatographic methods. Thus, the proposed microfluidic-based method is proposed to be used as a time- and cost-effective monitoring method for the analysis of AP and PHE.

Lateral flow assays (LFA) as an alternative medical diagnosis method for detection of virus species: The intertwine of nanotechnology with sensing strategies.

Viruses are responsible for multiple infections in humans that impose huge health burdens on individuals and populations worldwide. Therefore, numerous diagnostic methods and strategies have been developed for prevention, management, and decreasing the burden of viral diseases, each having its advantages and limitations. Viral infections are commonly detected using serological and nucleic acid-based methods. However, these conventional and clinical approaches have some limitations that can be resolved by implementing other detector devices. Therefore, the search for sensitive, selective, portable, and costless approaches as efficient alternative clinical methods for point of care testing (POCT) analysis has gained much attention in recent years. POCT is one of the ultimate goals in virus detection, and thus, the tests need to be rapid, specific, sensitive, accessible, and user-friendly. In this review, after a brief overview of viruses and their characteristics, the conventional viral detection methods, the clinical approaches, and their advantages and shortcomings are firstly explained. Then, LFA systems working principles, benefits, classification are discussed. Furthermore, the studies regarding designing and employing LFAs in diagnosing different types of viruses, especially SARS-CoV-2 as a main concern worldwide and innovations in the LFAs' approaches and designs, are comprehensively discussed here. Furthermore, several strategies addressed in some studies for overcoming LFA limitations like low sensitivity are reviewed. Numerous techniques are adopted to increase sensitivity and perform quantitative detection. Employing several visualization methods, using different labeling reporters, integrating LFAs with other detection methods to benefit from both LFA and the integrated detection device advantages, and designing unique membranes to increase reagent reactivity, are some of the approaches that are highlighted.

Nanoscale Metal-Organic Frameworks: Recent developments in synthesis, modifications and bioimaging applications.

Porous Metal-Organic Frameworks (MOFs) have emerged as eye-catching materials in recent years. They are widely used in numerous fields of chemistry thanks to their desirable properties. MOFs have a key role in the development of bioimaging platforms that are hopefully expected to effectually pave the way for accurate and selective detection and diagnosis of abnormalities. Recently, many types of MOFs have been employed for detection of RNA, DNA, enzyme activity and small-biomolecules, as well as for magnetic resonance imaging (MRI) and computed tomography (CT), which are valuable methods for clinical analysis. The optimal performance of the MOF in the bio-imaging field depends on the core structure, synthesis method and modifications processes. In this review, we have attempted to present crucial parameters for designing and achieving an efficient MOF as bioimaging platforms, and provide a roadmap for researchers in this field. Moreover, the influence of modifications/fractionalizations on MOFs performance has been thoroughly discussed and challenging problems have been extensively addressed. Consideration is mainly focused on the principal concepts and applications that have been achieved to modify and synthesize advanced MOFs for future applications.

A novel engineered label-free Zn-based MOF/CMC/AuNPs electrochemical genosensor for highly sensitive determination of Haemophilus Influenzae in human plasma samples.

An innovative label-free DNA genosensing assay based on a direct hybridization followed by DPASV in the presence of [Fe(CN)6]4-/3- was developed for recognizing the H. influenza genome in human plasma samples. To attain this objective, Zn-based MOF was synthesized and combined with carboxymethyl cellulose (CMC), which were immobilized on the surface of Au electrode and AuNPs were immobilized on the Zn-based MOF/CMC/Au-modified electrode surface. The genosensing bio-assay provides high specificity, sensitivity, and good performance for the determination of L-fuculokinase gene from the Haemophilus influenza genome. Various characterization techniques were applied including Fe-SEM, EDS, FT-IR, and XRD for investigation of morphological features and particle size. Under optimal conditions LOD and LOQ were 1.48 fM and 3.23 fM, respectively. Moreover, a wide linear range was obtained ranging from 0.1 pM-10 nM for t-DNA. The recoveries and RSDs were 98.4-103% and 2.2-3.2, respectively. The fabricated biosensing assay presented high selective ability of one, two, and three-base mismatched sequences. In addition, negative control of the genosensing assay for investigation of the selectivity was performed by the t-DNAs of Salmonella typhimurium and Shigella flexneri bacteria. Likewise, reproducibility and repeatability of the related bio-assay were investigated. It is to be noted that the organized genosensing bio-assay can be straightforwardly reused and regenerated to assess the hybridization process.