Nanobiosensors and their role in detection of adulterants and contaminants in food products

Nanotechnology is a multifaceted technical and scientific field undergoing a fast expansion. Nanoparticles, quantum dots, nanotubes, nanorods, nanowires, nanochips and many more are being increasingly used for fabrication of nanosensors and nanobiosensors to increase the sensitivity and selectivity of reactions. Food safety is an extremely important concern in food industries since it is directly associated with effect of food on human health. Here in our review, we have not only described the newest information regarding methods and use of nanomaterials for construction of nanosensors but also their detection range, limit of detection (LOD) and applications for food safety. Precise nanosensors having improved sensitivity and low limit of detection were discussed in brief. Review is primarily focused on nanosensors employed for detection of adulterants and contaminants in food products such as meat products, milk, fruit juices and water samples.

Nanoparticles as a Tool for Alleviating Plant Stress: Mechanisms, Implications, and Challenges

Plants, being sessile, are continuously exposed to varietal environmental stressors, which consequently induce various bio-physiological changes in plants that hinder their growth and development. Oxidative stress is one of the undesirable consequences in plants triggered due to imbalance in their antioxidant defense system. Biochemical studies suggest that nanoparticles are known to affect the antioxidant system, photosynthesis, and DNA expression in plants. In addition, they are known to boost the capacity of antioxidant systems, thereby contributing to the tolerance of plants to oxidative stress. This review study attempts to present the overview of the role of nanoparticles in plant growth and development, especially emphasizing their role as antioxidants. Furthermore, the review delves into the intricate connections between nanoparticles and plant signaling pathways, highlighting their influence on gene expression and stress-responsive mechanisms. Finally, the implications of nanoparticle-assisted antioxidant strategies in sustainable agriculture, considering their potential to enhance crop yield, stress tolerance, and overall plant resilience, are discussed.

Nanozyme as detector and remediator to environmental pollutants: between current situation and future prospective

The term "nanozyme" refers to a nanomaterial possessing enzymatic capabilities, and in recent years, the field of nanozymes has experienced rapid advancement. Nanozymes offer distinct advantages over natural enzymes, including ease of production, cost-effectiveness, prolonged storage capabilities, and exceptional environmental stability. In this review, we provide a concise overview of various common applications of nanozymes, encompassing the detection and removal of pollutants such as pathogens, toxic ions, pesticides, phenols, organic contaminants, air pollution, and antibiotic residues. Furthermore, our focus is directed towards the potential challenges and future developments within the realm of nanozymes. The burgeoning applications of nanozymes in bioscience and technology have kindled significant interest in research in this domain, and it is anticipated that nanozymes will soon become a topic of explosive discussion.

Surface modification strategies and the functional mechanisms of gold nanozyme in biosensing and bioassay

Gold nanozymes (GNZs) have been widely used in biosensing and bioassay due to their interesting catalytic activities that enable the substitution of natural enzyme. This review explains different catalytic activities of GNZs that can be achieved by applying different modifications to their surface. The role of Gold nanoparticles (GNPs) in mimicking oxidoreductase, helicase, phosphatase were introduced. Moreover, the effect of surface properties and modifications on each catalytic activity was thoroughly discussed. The application of GNZs in biosensing and bioassay was classified in five categories based on the combination of the enzyme like activities and enhancing/inhibition of the catalytic activities in presence of the target analyte/s that is realized by proper surface modification engineering. These categories include catalytic activity enhancer, reversible catalytic activity inhibitor, binding selectivity enhancer, agglomeration base, and multienzyme like activity, which are explained and exemplified in this review. It also gives examples of those modifications that enable the application of GNZs for in vivo biosensing and bioassays.

Preparation of bifunctional monomer molecularly imprinted polymer filled solid-phase extraction for sensitivity improvement of quantitative analysis of sulfonamide in milk

To solve the problems of unstable adsorption performance and high organic solvent consumption of traditional molecular imprinting materials, we developed a water-resistant and highly adsorptive molecularly imprinted sulfamethazine polymer (MIP) through a novel synthetic strategy consisting of the application of mixed functional monomers combined with hydrophobic crosslinkers. The results showed that the imprinting factor of the prepared MIP was increased from 0.93 to 4.38, and that the relative selection coefficient k' was 5.59. With the application of the material to be developed as a solid-phase extraction (SPE) filler for sulfonamides (SAs) in milk combined with UPLC-MS/MS, the validated method showed a sensitive quantification limit (0.89 µg/kg), a steady recovery (95.55%-97.97%) and an excellent precision (0.08%-2.92% RSD). Moreover, after 5 times usage, the recovery rate of MIP-SPE was still above 90%. Therefore, the prepared materials showed high performance of molecular adsorption and were water-resistant, which was also considered an excellent filler of SPE for SAs extraction in food or other fields.

Development of an Immunoassay Method for the Sensitive Detection of Histamine and Tryptamine in Foods Based on a CuO@Au Nanoenzyme Label and Molecularly Imprinted Biomimetic Antibody

In this paper, a novel biomimetic enzyme-linked immunoassay method (BELISA) was successfully established for the detection of histamine and tryptamine, based on catalytically active cupric oxide@gold nanoparticles (CuO@Au NPs) as a marker and a molecularly imprinted polymer (MIP) as the biomimetic antibody. Under optimized conditions, the detection limitations of the BELISA method for histamine and tryptamine were 0.04 mg L^-1 and 0.14 mg L^-1, respectively. For liquor spiked with histamine and tryptamine, the BELISA method delivered satisfactory recoveries ranging from 89.90% to 115.00%. Furthermore, the levels of histamine and tryptamine in fish, soy sauce, and rice vinegar samples were detected by the BELISA method and a high performance liquid chromatography method, with no significant difference between the two methods being found. Although the catalytic activity of nanozymes is still lower than that of natural enzymes, the BELISA method could still sensitively determine the histamine and tryptamine levels in food samples.

Recent Advancements in Nanobiosensors: Current Trends, Challenges, Applications, and Future Scope

In recent years, there has been immense advancement in the development of nanobiosensors as these are a fundamental need of the hour that act as a potential candidate integrated with point-of-care-testing for several applications, such as healthcare, the environment, energy harvesting, electronics, and the food industry. Nanomaterials have an important part in efficiently sensing bioreceptors such as cells, enzymes, and antibodies to develop biosensors with high selectivity, peculiarity, and sensibility. It is virtually impossible in science and technology to perform any application without nanomaterials. Nanomaterials are distinguished from fine particles used for numerous applications as a result of being unique in properties such as electrical, thermal, chemical, optical, mechanical, and physical. The combination of nanostructured materials and biosensors is generally known as nanobiosensor technology. These miniaturized nanobiosensors are revolutionizing the healthcare domain for sensing, monitoring, and diagnosing pathogens, viruses, and bacteria. However, the conventional approach is time-consuming, expensive, laborious, and requires sophisticated instruments with skilled operators. Further, automating and integrating is quite a challenging process. Thus, there is a considerable demand for the development of nanobiosensors that can be used along with the POCT module for testing real samples. Additionally, with the advent of nano/biotechnology and the impact on designing portable ultrasensitive devices, it can be stated that it is probably one of the most capable ways of overcoming the aforementioned problems concerning the cumulative requirement for the development of a rapid, economical, and highly sensible device for analyzing applications within biomedical diagnostics, energy harvesting, the environment, food and water, agriculture, and the pharmaceutical industry.

Molecular Imprinting on Nanozymes for Sensing Applications

As part of the biomimetic enzyme field, nanomaterial-based artificial enzymes, or nanozymes, have been recognized as highly stable and low-cost alternatives to their natural counterparts. The discovery of enzyme-like activities in nanomaterials triggered a broad range of designs with various composition, size, and shape. An overview of the properties of nanozymes is given, including some examples of enzyme mimics for multiple biosensing approaches. The limitations of nanozymes regarding lack of selectivity and low catalytic efficiency may be surpassed by their easy surface modification, and it is possible to tune specific properties. From this perspective, molecularly imprinted polymers have been successfully combined with nanozymes as biomimetic receptors conferring selectivity and improving catalytic performance. Compelling works on constructing imprinted polymer layers on nanozymes to achieve enhanced catalytic efficiency and selective recognition, requisites for broad implementation in biosensing devices, are reviewed. Multimodal biomimetic enzyme-like biosensing platforms can offer additional advantages concerning responsiveness to different microenvironments and external stimuli. Ultimately, progress in biomimetic imprinted nanozymes may open new horizons in a wide range of biosensing applications.