Nanomaterials Enabled and Bio/Chemical Analytical Sensors for Acrylamide Detection in Thermally Processed Foods: Advances and Outlook

A ratiometric fluorescent "off-on" sensor for acrylamide detection in toast based on red-emitting copper nanoclusters stabilized by bovine serum albumin

Acrylamide, as a Class 2A carcinogen, poses serious threats to human health. To achieve rapid and accurate determination of acrylamide in food, a ratiometric fluorescent "off-on" sensor was designed by incorporating red-emitting copper nanoclusters and glutathione. Copper nanoclusters with bimodal emission at 395 nm and 650 nm (excited at 310 nm) were synthesized by using bovine serum albumin as the ligand and ascorbic acid as the reductant. With glutathione addition, the fluorescence intensity at 650 nm gradually decreased, while the case at 395 nm slightly increased. The quenched fluorescence at 650 nm was subsequently restored by acrylamide through thiol-ene Michael addition reaction between acrylamide and glutathione. The constructed sensor showed excellent performance towards acrylamide detection in the range of 5-300 μM with a detection limit of 1.48 μM, and was further applied to real-sample detection of acrylamide in toast and exhibited good recoveries (90.29-101.30 %), indicating potential applications of this sensor.

Perovskite Nanocrystals: Superior Luminogens for Food Quality Detection Analysis

With the global limited food resources receiving grievous damage from frequent climate changes and ascending global food demand resulting from increasing population growth, perovskite nanocrystals with distinctive photoelectric properties have emerged as attractive and prospective luminogens for the exploitation of rapid, easy operation, low cost, highly accurate, excellently sensitive, and good selective biosensors to detect foodborne hazards in food practices. Perovskite nanocrystals have demonstrated supreme advantages in luminescent biosensing for food products due to their high photoluminescence (PL) quantum yield, narrow full width at half-maximum PL, tunable PL in the entire visible spectrum, easy preparation, and various modification strategies compared with conventional semiconductors. Herein, we have carried out a comprehensive discussion concerning perovskite nanocrystals as luminogens in the application of high-performance biosensing of foodborne hazards for food products, including a brief introduction of perovskite nanocrystals, perovskite nanocrystal-based biosensors, and their application in different categories of food products. Finally, the challenges and opportunities faced by perovskite nanocrystals as superior luminogens were proposed to promote their practicality in the future food supply.

Dietary Acrylamide: A Detailed Review on Formation, Detection, Mitigation, and Its Health Impacts

In today's fast-paced world, people increasingly rely on a variety of processed foods due to their busy lifestyles. The enhanced flavors, vibrant colors, and ease of accessibility at reasonable prices have made ready-to-eat foods the easiest and simplest choice to satiate hunger, especially those that undergo thermal processing. However, these foods often contain an unsaturated amide called 'Acrylamide', known by its chemical name 2-propenamide, which is a contaminant formed when a carbohydrate- or protein-rich food product is thermally processed at more than 120 °C through methods like frying, baking, or roasting. Consuming foods with elevated levels of acrylamide can induce harmful toxicity such as neurotoxicity, hepatoxicity, cardiovascular toxicity, reproductive toxicity, and prenatal and postnatal toxicity. This review delves into the major pathways and factors influencing acrylamide formation in food, discusses its adverse effects on human health, and explores recent techniques for the detection and mitigation of acrylamide in food. This review could be of interest to a wide audience in the food industry that manufactures processed foods. A multi-faceted strategy is necessary to identify and resolve the factors responsible for the browning of food, ensure safety standards, and preserve essential food quality traits.

Artificial enzyme innovations in electrochemical devices: advancing wearable and portable sensing technologies

With the rapid evolution of sensing technologies, the integration of nanoscale catalysts, particularly those mimicking enzymatic functions, into electrochemical devices has surfaced as a pivotal advancement. These catalysts, dubbed artificial enzymes, embody a blend of heightened sensitivity, selectivity, and durability, laying the groundwork for innovative applications in real-time health monitoring and environmental detection. This minireview penetrates into the fundamental principles of electrochemical sensing, elucidating the unique attributes that establish artificial enzymes as foundational elements in this field. We spotlight a range of innovations where these catalysts have been proficiently incorporated into wearable and portable platforms. Navigating the pathway of amalgamating these nanoscale wonders into consumer-appealing devices presents a multitude of challenges; nevertheless, the progress made thus far signals a promising trajectory. As the intersection of materials science, biochemistry, and electronics progressively intensifies, a flourishing future seems imminent for artificial enzyme-infused electrochemical devices, with the potential to redefine the landscapes of wearable health diagnostics and portable sensing solutions.

Thiol-ene click derivatization reaction coupled with ratiometric surface-enhanced Raman scattering for reproducible and accurate determination of acrylamide

Acrylamide (AA) is a carcinogen mainly ingested through food and drinking water, making its accurate determination crucial for both food safety and environmental protection. Herein, we proposed a derivatization-based ratiometric surface-enhanced Raman scattering (SERS) method for the quantification of AA. High density Au NPs were anchored to the surface of Cu-TCPP MOF nanosheets (MOFNs) to form the SERS sensor. The abundant Raman "hot spots" at the nanogaps generated by the Au NPs and the internal standard (IS) signal provided by Cu-TCPP MOFNs improved the sensitivity and quantitative accuracy of the method. Following the thiol-ene click derivatization reaction between p-aminothiophenol (PATP) and AA, the Raman peak intensity ratio (I1080/I395) was employed to quantify AA. The linear range was 0.1 nM to 10 μM, and the limit of detection (LOD) was as low as 0.08 nM. Trace amounts of AA in food and water samples were successfully determined using this method.

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.

Quercetin Alleviates Acrylamide-Induced Liver Injury by Inhibiting Autophagy-Dependent Ferroptosis

Acrylamide (ACR) generated in carbohydrate-rich foods during thermal processing has been demonstrated to exhibit hepatotoxicity. As one of the most consumed flavonoids with diet, quercetin (QCT) possesses the ability to protect against ACR-induced toxicity, albeit its mechanism is unclear. Herein, we discovered that QCT alleviated ACR-induced elevated levels of reactive oxygen species (ROS), AST, and ALT in mice. RNA-seq analysis revealed that QCT reversed the ferroptosis signaling pathway upregulated by ACR. Subsequently, experiments indicated that QCT inhibited ACR-induced ferroptosis through the reduction of oxidative stress. With autophagy inhibitor chloroquine, we further confirmed that QCT suppressed ACR-induced ferroptosis by inhibiting oxidative stress-driven autophagy. Additionally, QCT specifically reacted with autophagic cargo receptor NCOA4, blocked the degradation of iron storage protein FTH1, and eventually downregulated the intracellular iron levels and the consequent ferroptosis. Collectively, our results presented a unique approach to alleviate ACR-induced liver injury by targeting ferroptosis with QCT.

A smartphone-assisted ultrasensitive detection of acrylamide in thermally processed snacks using CQD@Au NP integrated FRET sensor

Selective, sensitive, and accurate detection of acrylamide (AA) in thermally processed food is a great challenge for food safety. This paper describes a "turn-on" fluorescence strategy to detect AA in real samples. Herein, the fluorescence intensity of glutathione-modified carbon quantum dots (GSHCQDs) was quenched initially upon the addition of gold nanoparticles (Au NPs) via fluorescence resonance electron transfer (FRET) to form a quenched GSHCQD-Au nanoprobe. When AA was introduced to the quenched GSHCQD-Au nanoprobe, the strong thiol-ene Michael addition (M-A) reaction among the -SH group of GSHCQD and AA occurred which releases GSHCQD to the medium and FL intensity at 520 nm is regained. The GSHCQD-Au nanoprobe can detect the AA in a normal aqueous solution (pH 7) selectively over a short response time of 5 min. Under the optimized conditions, the detection limit of AA was obtained to be 0.12 pM, over a wide linear range of 0-200 nM. Especially, this FRET-based sensing method was utilized successfully for the sensitive detection of AA using an RGB app installed on a smartphone, opening a new approach for the smart sensing of food contaminants.

Assessing Meat Freshness via Nanotechnology Biosensors: Is the World Prepared for Lightning-Fast Pace Methods?

In the rapidly evolving field of food science, nanotechnology-based biosensors are one of the most intriguing techniques for tracking meat freshness. Purine derivatives, especially hypoxanthine and xanthine, are important signs of food going bad, especially in meat and meat products. This article compares the analytical performance parameters of traditional biosensor techniques and nanotechnology-based biosensor techniques that can be used to find purine derivatives in meat samples. In the introduction, we discussed the significance of purine metabolisms as analytes in the field of food science. Traditional methods of analysis and biosensors based on nanotechnology were also briefly explained. A comprehensive section of conventional and nanotechnology-based biosensing techniques is covered in detail, along with their analytical performance parameters (selectivity, sensitivity, linearity, and detection limit) in meat samples. Furthermore, the comparison of the methods above was thoroughly explained. In the last part, the pros and cons of the methods and the future of the nanotechnology-based biosensors that have been created are discussed.

Fluorescent garlic-capped Ag nanoparticles as dual sensors for the detection of acetone and acrylamide

In order to protect human health from the adverse impacts of acrylamide and acetone, simple analytical processes are required to detect low concentrations of acrylamide and acetone. Dual functional garlic-capped silver nanoparticles (G-Ag NPs) have been used as fluorescent sensors for acrylamide and acetone. This technique depends on the quenching of the photoluminescence (PL) intensity of G-Ag NPs with the interaction of either acrylamide or acetone. This fluorescent probe presented high selectivity toward acrylamide with a wide linear response of 0.01-6 mM with a limit of detection (LOD) of 2.9 μM. Moreover, this probe also acted as a selective and sensitive fluorescent sensor for the detection of acetone in the range of 0.1-17 mM with LOD of 55 μM. The applicability of G-Ag NPs as a proposed sensor for acrylamide was evaluated using a potato chips sample with a recovery percentage of 102.4%. Acetone concentration is also quantified in human urine samples and the recoveries ranged from 98.8 to 101.7%. Repeatability and reproducibility studies for acrylamide and acetone offered relative standard deviation (RSD) of 0.9% and 1.5%, and 0.77% and 1.1%, respectively.

Nanozyme-encoded luminescent detection for food safety analysis: An overview of mechanisms and recent applications

With the rapid growth in global food production, delivery, and consumption, reformative food analytical techniques are required to satisfy the monitoring requirements of speed and high sensitivity. Nanozyme-encoded luminescent detections (NLDs) integrating nanozyme-based rapid detections with luminescent output signals have emerged as powerful methods for food safety monitoring, not only because of their preeminent performance in analysis, such as rapid, facile, low background signal, and ultrasensitive, but also due to their strong attractiveness for future sensing research. However, the lack of a full understanding of the fundamentals of NLDs for food safety detection technologies limits their further application. In this review, a systematic overview of the mechanisms of NLDs and their applications in the food industry is summarized, which covers the nanozyme-mimicking types and their luminescent signal generation mechanisms, as well as their applications in monitoring common foodborne contaminants. As demonstrated by previous studies, NLDs are bridging the gap to practical-oriented food analytical technologies and various opportunities to improve their food analytical performance to be considered in the future are proposed.

Construction of ratiometric fluorescence sensor and test strip with smartphone based on molecularly imprinted dual-emission quantum dots for the selective and sensitive detection of domoic acid

Domoic acid (DA), a highly neurotoxic metabolite produced by phytoplankton, contaminates seafood products and threats humankind. Herein, we have proposed a molecular imprinting fluorescence sensor with internal standard ratiometric mode for sensing of DA in seafood and seawater. In this study, the silicon-coated blue luminous carbon dots (B-CDs@SiO₂) and CdTe acted as reference probe (430 nm) and response probe (610 nm), respectively. Subsequently, the two probes were assembled and the molecularly imprinted polymer (MIP) was introduced as the recognition element to construct the core component of the sensor (B-CDs@SiO₂/CdTe MIP). When DA exists, it can be specifically adsorbed by the amino-rich imprinted sites on surface of B-CDs@SiO₂/CdTe MIP and further assembled into the hydrogen-bonds complex, which can lead to the decrease in the fluorescence signal of MIP at 610 nm owing to the electron transfer from CdTe to DA. However, the fluorescence signal of MIP at 430 nm is not affected because of the protection of silica layer. Based on this principle, the designed internal standard ratiometric fluorescence sensor reveals high sensitivity, excellent selectivity, and wide linear range of 0.03-1 μM with a detection limit of 18 nM. Further, the portable fluorescent test strip with smartphone has been designed for semi-quantitative sensing of DA, which has potential application prospects for field analysis.

Ratiometric Fluorescent Metal-Organic Framework Biosensor for Ultrasensitive Detection of Acrylamide

Acrylamide is a neurotoxin and carcinogen that forms during the thermal processing of food, inflicting irreversible harm to human health. Herein, a ratiometric fluorescence biosensor based on a 6-carboxyfluorescein-labeled aptamer (FAM-ssDNA) and porphyrin metal-organic framework (PCN-224) was developed. PCN-224 exhibits strong adsorption capacity for FAM-ssDNA and also quenches the fluorescence of FAM-ssDNA via fluorescence resonance energy transfer and photoinduced electron transfer. FAM-ssDNA hybridizes with complementary DNA to form double-stranded DNA (FAM-dsDNA), which is liberated from the PCN-224 surface, resulting in fluorescence recovery. However, the intrinsic fluorescence of the ligand remains unchanged. Acrylamide can create an adduct with FAM-ssDNA and inhibit the hybridization of FAM-dsDNA, thus realizing ratiometric sensing of acrylamide. The proposed biosensor displays excellent detection performance from 10 nM∼0.5 mM with a limit of detection of 1.9 nM. In conclusion, a fabricated biosensor was successfully applied to detect acrylamide in thermally processed food, and the results were consistent with those of high-performance liquid chromatography.

A fluorescence biosensor based on double-stranded DNA and a cationic conjugated polymer coupled with exonuclease III for acrylamide detection

As a toxic substance on human health produced in food thermal treatment, simple analytical approaches are highly desired for the detection of acrylamide (ACR) in foods. With the aid of exonuclease III (Exo III), a simple fluorescence sensor was proposed based on carboxyfluorescein-labeled double-stranded DNA (FAM-dsDNA) and a cationic conjugated polymer (PFP). Fluorescence resonance energy transfer (FRET) efficiency between FAM and PFP was changed with and without ACR. When ACR was present, ACR and single-stranded DNA (P1, ssDNA) formed an adduct, allowing free FAM-labeled complementarity strand DNA (P2, FAM-csDNA) to appear in the solution and avoiding the digestion of P2 by Exo III. After the addition of PFP, the interaction of PFP and FAM induced strong FRET. Under optimized conditions, ACR was detected with a limit of detection (LOD) of 0.16 μM. According to this biosensor, a LOD of 1.3 μM in water extract samples was observed with a good recovery rate (95-110 %).

Detection of Acrylamide in Foodstuffs by Nanobody-Based Immunoassays

Acrylamide is toxic aliphatic amide formed via the Maillard reaction between asparagine and reducing sugars during thermal processing of food. Herein, a specific nanobody termed Nb-7E against the acrylamide derivative xanthyl acrylamide (XAA) was isolated from an immunized phage display library and confirmed to be able to detect acrylamide. First, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was established for acrylamide with a limit of detection (LOD) of 0.089 μg/mL and working range from 0.23 to 5.6 μg/mL. Furthermore, an enhanced electrochemical immunoassay (ECIA) was developed based on the optimized reaction conditions. The LOD was as low as 0.033 μg/mL, threefold improved compared to that of ic-ELISA, and a wider linear detection range from 0.39 to 50.0 μg/mL was achieved. The average recoveries ranged from 88.29 to 111.76% in spiked baked biscuits and potato crisps. Finally, the analytical performance of the ECIA was validated by standard ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS).

Recent Progress on Highly Selective and Sensitive Electrochemical Aptamer-based Sensors

Highly selective, sensitive, and stable biosensors are essential for the molecular level understanding of many physiological activities and diseases. Electrochemical aptamer-based (E-AB) sensor is an appealing platform for measurement in biological system, attributing to the combined advantages of high selectivity of the aptamer and high sensitivity of electrochemical analysis. This review summarizes the latest development of E-AB sensors, focuses on the modification strategies used in the fabrication of sensors and the sensing strategies for analytes of different sizes in biological system, and then looks forward to the challenges and prospects of the future development of electrochemical aptamer-based sensors.

A portable kit based on thiol-ene Michael addition for acrylamide detection in thermally processed foods

Accurate, sensitive, and selective analysis of acrylamide generated in thermally processed foods is of great significance for food safety. Herein, a novel acrylamide sensing platform is designed for both sensitive on-site colorimetric analysis and accurate UV-vis spectroscopy quantification, by integrating thiol-ene Michael addition with gold nanoparticles-mediated catalytical oxidation. The Michael addition reaction between acrylamide and glutathione efficiently alleviates glutathione-induced catalytic activity inhibition of gold nanoparticles, evoking the chromogenic reaction of H₂O₂-mediated 3,3',5,5'-tetramethylbenzidine. With increasing the concentration of acrylamide, the oxidation of 3,3',5,5'-tetramethylbenzidine is accelerated, presenting a series of shades from colorless to blue. The sensing platform exhibits excellent detection performance of acrylamide in the range of 0.5-175 μM with a detection limit of 0.16 μM, and is successfully employed in food samples. Especially, a portable assay kit based on the proposed platform is developed for visual determination of acrylamide, opening an avenue for smart sensors of food safety hazards.

Recent Progress of Nanostructured Sensing Materials from 0D to 3D: Overview of Structure-Property-Application Relationship for Gas Sensors

Along with the progress of nanoscience and nanotechnology, nanomaterials with attractive structural and functional properties have gained more attention than ever before, especially in the field of electronic sensors. In recent years, the gas sensing devices have made great achievement and also created wide application prospects, which leads to a new wave of research for designing advanced sensing materials. There is no doubt that the characteristics are highly governed by the sensitive layers. For this reason, important advances for the outstanding, novel sensing materials with different dimensional structures including 0D, 1D, 2D, and 3D are reported and summarized systematically. The sensing materials cover noble metals, metal oxide semiconductors, carbon nanomaterials, metal dichalcogenides, g-C₃ N₄ , MXenes, and complex composites. Discussion is also extended to the relation between sensing performances and their structure, electronic properties, and surface chemistry. In addition, some gas sensing related applications are also highlighted, including environment monitoring, breath analysis, food quality and safety, and flexible wearable electronics, from current situation and the facing challenges to the future research perspectives.