Recent advancements in the specific determination of carcinoembryonic antigens using MOF-based immunosensors.

Carcinoembryonic antigens (CEAs) are prominent cancer biomarkers that enable the early detection of numerous cancers. For effective CEA screening, rapid, portable, efficient, and sensitive diagnosis approaches should be devised. Metal-organic frameworks (MOFs) are porous crystalline materials that have received major attention for application in high-efficiency signal probes owing to their advantages such as large specific surface area, superior chemical stability and tunability, high porosity, easy surface functional modification, and adjustable size and morphology. Immunoassay strategies using antigen-antibody specific interaction are one of the imperative means for rapid and accurate measurement of target molecules in biochemical fields. The emerging MOFs and their nanocomposites are synthesized with excellent features, providing promising potential for immunoassays. This article outlines the recent breakthroughs in the synthesis approaches of MOFs and overall functionalization mechanisms of MOFs with antigen/antibody and their uses in the CEA immunoassays, which operate according to electrochemical, electrochemiluminescent and colorimetric techniques. The prospects and limitations of the preparation and immunoassay applications of MOF-derived hybrid nanocomposites are also discussed at the end.

Applications of Advanced Materials for Non-Enzymatic Glucose Monitoring: From Invasive to the Wearable Device.

Diabetes mellitus (DM) is a global health problem leading to many complications and disabilities in life adjusting activities and even dead. Monitoring glucose levels is a key factor in diagnosis and management of DM. Conventional glucose sensors consisted of immobilized enzymes, are so susceptible to environmental conditions. In this way, nonenzymatic biosensors have attracted extensive attentions in many clinical diagnostics applications. To date, the finger pricking test is a common enzyme-based glucometer that is an invasive and inconvenient and may lead to infections in the injection sites. So, working on the possibility of cutaneous or subcutaneous insertion of devices as a noninvasive or minimally-invasive systems for continuous glucose controlling approaches through human biofluids (blood, perspiration, tears, saliva, etc.) have stimulated growing interest. This review summarizes recent nonenzymatic and noninvasive biofluids glucose monitoring systems which are highly resilience and stretchable to continuously adapt to body movements during common physical activity. Sensors are based on their constituent materials including carbon-based, metal nanoparticles, polymer, and hydrogel systems are classified for electrochemical, and optical glucose detection. Finally, we address the drawbacks and challenges of enzyme-free sensors which are aroused sustaining research passion to be used in point-of-care medical diagnostics applications.

Aptasensing of ciprofloxacin residue using graphene oxide modified with gold nanoparticles and branched polyethyleneimine.

Precise monitoring of antibiotic residues in aqueous solution is of vital significance for safeguarding the environment and food resources. Herein, a convenient platform was fabricated for the electrochemical assay of ciprofloxacin (CFX) in real milk samples using aminated aptamer and graphene oxide nanogold-functionalized branched polyethyleneimine (GO-PEI-AuNPs) nanocomposite. For the first time, a gold electrode was modified with GO-PEI-AuNPs. The modified surface endowed excellent electrochemical substrates with large surface areas, excellent electron transfer rates, and suitable capabilities to firmly attach high amounts of aptamer. After further modification of substrate with CFX specific aptamer a recognition probe enabling selective and sensitive determination of CFX was realized. All of the aptasensor fabrication steps were surveyed via cyclic voltammetry techniques. The construction and morphology of the GO-PEI-AuNPs composite were evaluated by UV-Vis spectroscopy, transmission electron microscopy, and field emission scanning electron microscopy. Under optimal conditions, the suggested scaffold can offer an acceptable linear range of 0.001 to 100 µM and a low limit of quantification of 0.001 µM for selective and sensitive monitoring of CFX in real samples. The effectiveness of the apta-assay was confirmed by detection of CFX in pasteurized and local milk samples for which suitable analytical results were achieved. It is expected that the developed substrate can be facilely extended to other aptamer-based multiplex screening platforms in actual food and environmental samples.

Nanomaterial based PVA nanocomposite hydrogels for biomedical sensing: Advances toward designing the ideal flexible/wearable nanoprobes.

In today's world, the progress of wearable tools has gained increasing momentum. Notably, the demand for stretchable strain sensors has considerably increased owing to various potential and emerging applications like human motion monitoring, soft robotics, prosthetics, and electronic skin. Hydrogels possess excellent biocompatibility, flexibility, and stretchability that render them ideal candidates for flexible/wearable substrates. Among them, enormous efforts were focused on the progress of polyvinyl alcohol (PVA) hydrogels to realize multifunctional wearable sensing through using additives/nanofillers/functional groups to modify the hydrogel network. Herein, this review offers an up-to-date and comprehensive summary of the research progress of PVA hydrogel-based wearable sensors in view of their properties, strain sensory efficiency, and potential applications, followed by specifically highlighting their probes using metallic/non-metallic, liquid metal (LM), 2D materials, bio-nanomaterials, and polymer nanofillers. Indeed, flexible electrodes and strain/pressure sensing performance of designed PVA hydrogels for their effective sensing are described. The representative cases are carefully selected and discussed regarding the construction, merits and demerits, respectively. Finally, the necessity and requirements for future advances of conductive and stretchable hydrogels engaged in the wearable strain sensors are also presented, followed by opportunities and challenges.

Rational design of smart nano-platforms based on antifouling-nanomaterials toward multifunctional bioanalysis.

The ability to design nanoprobe devices with the capability of quantitative/qualitative operation in complex media will probably underpin the main upcoming progress in healthcare research and development. However, the biomolecules abundances in real samples can considerably alter the interface performance, where unwanted adsorption/adhesion can block signal response and significantly decrease the specificity of the assay. Herein, this review firstly offers a brief outline of several significances of fabricating high-sensitivity and low-background interfaces to adjust various targets' behaviors induced via bioactive molecules on the surface. Besides, some important strategies to resist non-specific protein adsorption and cell adhesion, followed by imperative categories of antifouling reagents utilized in the construction of high-performance solid sensory interfaces, are discussed. The next section specifically highlights the various nanocomposite probes based on antifouling-nanomaterials for electrode modification containing carbon nanomaterials, noble metal nanoparticles, magnetic nanoparticles, polymer, and silicon-based materials in terms of nanoparticles, rods, or porous materials through optical or chemical strategies. We specially outline those nanoprobes that are capable of identification in complex media or those using new constructions/methods. Finally, the necessity and requirements for future advances in this emerging field are also presented, followed by opportunities and challenges.

Synergizing Functional Nanomaterials with Aptamers Based on Electrochemical Strategies for Pesticide Detection: Current Status and Perspectives.

Owing to the high toxicity and large-scale use of pesticides, it is imperative to develop selective, sensitive, portable, and convenient sensors for rapid monitoring of pesticide. Therefore, the electrochemical detection platform offers a promising analytical approach since it is easy to operate, economical, efficient, and user-friendly. Meanwhile, with advances in functional nanomaterials and aptamer selection technologies, numerous sensitivity-enhancement techniques alongside a widespread range of smart nanomaterials have been merged to construct novel aptamer probes to use in the biosensing field. Hence, this study intends to highlight recent development and promising applications on the functional nanomaterials with aptamers for pesticides detection based on electrochemical strategies. We also reviewed the current novel aptamer-functionalized microdevices for the portability of pesticides sensors. Furthermore, the major challenges and future prospects in this field are also discussed to provide ideas for further research.

Carbon-based aerogels for biomedical sensing: Advances toward designing the ideal sensor.

Carbon based aerogels are special solid-state materials comprised of interconnected networks of 3D nanostructures with high amount of air-filled nanoporous. They expand the structural properties along with physicochemical characteristics of nanoscale construction blocks to macroscale, and incorporate distinctive attributes of aerogels, like large surface area, high porosity, and low density, with particular features of the different constituents. These features impart aerogels with rapid response signal, high selectivity, and ultra-sensitivity for sensing diverse targets in biomedical media. This has prompted researchers to develop a variety of aerogel-based sensors with encouraging achievements. Hence, this work outlines sensing applications of aerogel-based sensors with a comprehensive overview on the carbon aerogel hybrid materials and their analytical performances. Authors tried to list advantages and limitations of the developed approach and introduced more potent research for possible devices designing. We also point out some challenges and future perspectives related to the improvement of high-efficiency aerogel-based sensors.

Sensitive aptasensing of ciprofloxacin residues in raw milk samples using reduced graphene oxide and nanogold-functionalized poly(amidoamine) dendrimer: An innovative apta-platform towards electroanalysis of antibiotics.

The constant need of humans and animals for food resources was led to overuse of antibiotics as vital medicines. In this regard, we are now facing major concern about the risks on the food safety and environment owing to their uncontrolled disposal. Hence, the progress of simple and sensitive approaches for fast monitoring of antibiotic levels is highly desirable. Here, we aimed to describe a new sensitive and easy-to use strategy based on electrochemical single off apta-assay toward ciprofloxacin (CFX). A novel interface using 3D Au-PAMAM/rGO have been designed via full electrochemically technique on the surface of glassy carbon electrodes (GCE) and evaluated with cyclic voltammetry method. Firstly, rGO with large amount of active functional groups as substrate was fabricated on the GCE electrode. Thereby, the 3D Au-PAMAM nanocomposite was synthesized and covalently electrodeposited onto the rGO-GCE modified surface. The structure and morphology of 3D Au-PAMAM were studied using UV-Vis spectroscopy, Field emission scanning electron microscopes (FE-SEM) and Transmission electron microscopy. Also, FE-SEM and Energy-dispersive X-ray spectroscopy (EDS) have been carry out to illustrate surface morphology of electrodes. The obtained results from square wave voltammetry, different pulse voltammetry, and chronoamperometry techniques implied that the suggested scaffold could be used as facile bio-device toward antibiotic detection with low limit of quantification (LLOQ) of 1 nM and a linear range of 1 µM-1 nM. Interestingly, the suggested aptasensor is successfully used to measure CFX residues in local and pasteurized milk samples. It can be deduced that Apt/rGO/3D Au-PAMAM/GCE as a novel biocompatible interface could offer suitable, cost-effective, reliable, rapid, and user-friendly sensing device for direct determination of CFX in real samples.

A stretchable glove sensor toward rapid monitoring of trifluralin: A new platform for the on-site recognition of herbicides based on wearable flexible sensor technology using lab-on-glove.

In this study, a flexible glove-based electrochemical sensor as a wearable point-of-use screening tool has been fabricated for defense and food security applications. To design the wearable glove-based sensor, we drew conductive patterns on the fingers of a rubber glove via gold@silver-modified graphene quantum dots (Au@Ag core-shell/graphene quantum dots [GQDs]) nano-ink with optimal thickness. Then, this platform is combined with a portable electrochemical analyzer for on-site detection of trifluralin pesticide in the range of 10 nM to 1 mM with the low limit of quantification (LLOQ) of 10 nM. The high efficiency and distinction of the trifluralin at specified concentrations in real leaf and apple samples were performed by simply touching with the glove and in spikes solution by immersing of fingertips. With their high sensitivity, selectivity, rapid, and easy operation pesticide analysis, these glove-embedded sensors can also be engaged in on-site monitor of other chemical threats and can be expanded to water and environmental samples.

Nanomaterials and new biorecognition molecules based surface plasmon resonance biosensors for mycotoxin detection.

Mycotoxins are highly toxic secondary metabolites, which may contaminate many types of food and feeds. These toxins have serious health risks for both human and animals. One of the effective ways to prevent food contamination and protect people against mycotoxins is based on timely detection. Several methods like enzyme-linked immunosorbent assay and affinity chromatography are commercially available for this purpose. Nevertheless, sensitive, fast, simple, low-cost, and portable devices are absolutely required for a fast point-of care information and making decisions. Application of biosensors appears to be a possible technique to meet this need for mycotoxins analyze. The present study has been focused on the literature update of smart using of biosensing for detection of mycotoxin at both academic and industrial levels in order to replace conventional chromatographic methods. Surface plasmon resonance (SPR) as one of the relatively novel and simple analytical method has been proven for rapid, sensitive, label-free detection and widely used for qualitative and quantitative analysis of multiplexed pollutant in real-time. This paper aims to provide an extensive overview on biosensors for mycotoxin detection by highlighting the main biorecognition elements. Moreover, SPR principles, assay formats, and signal enhancement are summarized.

Nanomaterials based surface plasmon resonance signal enhancement for detection of environmental pollutions.

Due to the nearby relationship between human health, socioeconomic development and environmental pollution, the detection and identification of environmental pollutants need more attention. Therefore, the development of suitable analytical devices that are sensitive, specific, precise, quick, and easy-to-use are required to resolve the increased request for legislative action on environmental pollution control and early detection of rising pollutants. Currently, the development of biosensing instruments attracted important attention because of their high selectivity, sensitivity, simplicity, reliability, low-cost and real-time response. Surface plasmon resonance (SPR) sensor as an example of portable, rapid, and smart biosensing devices widely used for qualitative and quantitative detection of multiplexed pollutant in real-time. Thus, SPR principles, assay formats, surface modification methods and signal enhancement are summarized in this review. Moreover, applications of SPR in the detection of pesticide, polycyclic aromatic hydrocarbons (PAHs), heavy metals and polychlorinated biphenyls (PCBs) over the past decade is discussed.

Development of an ultrasound-assisted emulsification microextraction method for the determination of chlorpyrifos and organochlorine pesticide residues in honey samples using gas chromatography with mass spectrometry.

A simple, rapid, and efficient ultrasound-assisted emulsification microextraction method followed by gas chromatography mass spectrometry in selected ion monitoring mode was developed for the determination of organochlorine pesticides in honey samples. The type and volume of organic extraction solvent, pH, effect of added salt content, and centrifuging time and speed were investigated. Under the optimum extraction conditions, 30 µL of 1, 2-dibromoethane (extraction solvent) was immersed into an ultrasonic bath for 1 min at 40°C. The limits of detection and quantification for all target pesticides were 0.003-0.06 and 0.01-0.2 ng/g, respectively. The extraction recovery was 91-100% and the enrichment factors were 168-192. The relative standard deviation for the method was <6% for intraday (n = 6) and <8% for interday precision (n = 4). The proposed method was successfully applied for the analysis of organochlorine pesticides in honey samples.

Dispersive Liquid-Liquid Microextraction for HPLC-UV Determination of PAHs in Milk.

A simple and rapid analytical method for the extraction and quantification of four polycyclic aromatic hydrocarbons in milk sample has been developed using dispersive liquid-liquid microextraction followed by the use of HPLC. Benzo(a)pyrene, benzo(a)anthracene, and benzo(b)fluoranthene were used as model compounds; the milk sample was spiked with these compounds to assess the extraction procedure. Experimental parameters that influence the extraction efficiency, including the nature and volume of the disperser and extraction solvents, pH, and the volume of milk sample, were optimized. Under the optimum extraction conditions (extraction solvent: chloroform, 200 µL; dispersive solvent: acetonitrile, 700 µL; and extraction time 5 s or less), the performance of the proposed method was evaluated. The chromatographic peak area was linear with concentrations in the range of 0.2-10 ng/mL(-1) and with correlation coefficients ranging from 0.9968 to 0.9985. The LODs, based on a S/N ratio of 3, ranged from 0.06 to 0.18 ng/mL(-1). The RSDs varied from 3.68 to 9.7% (n = 3). The recoveries of these compounds were from 88.38 to 100%. The performance of the present method was evaluated for the determination of polycyclic aromatic hydrocarbons in various types of milk samples.