An electrochemical biosensor based on hemoglobin-oligonucleotides-modified electrode for detection of acrylamide in potato fries

Acrylamide in food products and the role of electrochemical biosensors in its detection: a comprehensive review

In this review, the mechanisms of acrylamide formation in food, along with aspects related to its toxicity and associated consumption risks, are investigated, highlighting the potential impact on human health. European regulations regarding acrylamide content in food products are also addressed, emphasizing the importance of monitoring and detecting this substance in nutrition, by public health protection measures. The primary objective of the research is to explore and analyze innovative methods for detecting acrylamide in food, with a particular focus on electrochemical biosensors. This research direction is motivated by the need to develop rapid, sensitive, and efficient monitoring techniques for this toxic compound in food products, considering the associated consumption risks. The research has revealed several significant results. Studies have shown that electrochemical biosensors based on hemoglobin exhibited increased sensitivity and low detection limits, capable of detecting very low concentrations of acrylamide in processed foods. Additionally, it has been found that the use of functionalized nanomaterials, such as carbon nanotubes and gold nanoparticles, has led to the improvement of electrochemical biosensor performance in acrylamide detection. The integration of these technological innovations and functionalization strategies has enhanced the sensitivity, specificity, and stability of biosensors in measuring acrylamides. Thus, the results of this research offer promising perspectives for the development of precise and efficient methods for monitoring acrylamides in food, contributing to the improvement of food quality control and the protection of consumer health.

A label-free aptasensor for colorimetric detection of food toxin: Mediation of catalytically active gold nanozymes and smartphone imaging strategy

A portable colorimetric aptasensor was developed on the surface of a plastic sheet for on-site detection of acrylamide. The mechanism of aptasensor is based on the disruption of the aptamer complex with its complementary strand on the sensing zone, and subsequently, the catalytic activity of gold nanoparticles (AuNPs) for the reduction process of 4-nitrophenol (4-NP) in the presence of sodium borohydride (NaBH4). A yellow-to-colorless change of the sample solution revealed the target presence, easily discernible by the naked eye. The acrylamide quantification was accomplished using the smartphone imaging readout technique. The aptasensor detected the acrylamide concentration in the range of 0.01-500 nmol L-1 with a detection limit of 0.0024 nmol L-1. Coffee, potato chips, bread, and lake water samples were successfully analyzed by the aptasensor for their acrylamide content. The introduced aptasensor can pave a facile, cost-effective, portable, and user-friendly sensing tool for food safety control and environmental monitoring.

Recent advancements in nanomaterial based optical detection of food additives: a review

Food additives have become a critical component in the food industry. They are employed as preservatives to decelerate the negative effects of environmental and microbial factors on food quality. Currently, food additives are used for a variety of purposes, including colorants, flavor enhancers, nutritional supplements, etc., owing to improvements in the food industry. Since the usage of food additives has increased dramatically, the efficient monitoring of their acceptable levels in food products is quite necessary to mitigate the problems associated with their inappropriate use. The traditional methods used for detecting food additives are generally based on standard spectroscopic and chromatographic techniques. However, these analytical techniques are limited by their high instrumentation cost and time-consuming procedures. The emerging field of nanotechnology has enabled the development of highly sensitive and specific sensors to analyze food additives in a rapid manner. The current article emphasizes the need to detect various food additives owing to their potential negative effects on humans, animals, and the environment. In this article, the role of nanomaterials in the optical sensing of food additives has been discussed owing to their high accuracy, ease-of-use, and excellent sensitivity. The applications of nanosensors for the detection of various food additives have been elaborated with examples. The current article will assist policymakers in developing new rules and regulations to mitigate the adverse effects of toxic food additives on humans and the environment. In addition, the prospects of nanosensors for the optical detection of food additives at a commercial scale have been discussed to combat their irrational use in the food industry.

Toxicity, formation, contamination, determination and mitigation of acrylamide in thermally processed plant-based foods and herbal medicines: A review

Thermal processing is one of the important techniques for most of the plant-based food and herb medicines before consumption and application in order to meet the specific requirement. The plant and herbs are rich in amino acids and reducing sugars, and thermal processing may lead to Maillard reaction, resulting as a high risk of acrylamide pollution. Acrylamide, an organic pollutant that can be absorbed by the body through the respiratory tract, digestive tract, skin and mucous membranes, has potential carcinogenicity, neurological, genetic, reproductive and developmental toxicity. Therefore, it is significant to conduct pollution determination and risk assessment for quality assurance and security of medication. This review demonstrates state-of-the-art research of acrylamide focusing on the toxicity, formation, contamination, determination, and mitigation in taking food and herb medicine, to provide reference for scientific processing and ensure the security of consumers.

Facile synthesis of Ag@Fe3O4/ZnO nanomaterial for label-free electrochemical detection of methemoglobin in anemic patients

Methemoglobinemia (MetHb, Fe³⁺) is a chronic disease arising from the unequal distribution of oxyhemoglobin (HbFe²⁺, OHb) in the blood circulatory system. The oxidation of standard oxyhemoglobin forms methemoglobin, causing cyanosis (skin bluish staining). Methemoglobin cannot bind the pulmonary gaseous ligands such as oxygen (O₂) and carbon monoxide (CO). As an oxidizing agent, the biochemical approach (MetHb, Fe³⁺) is modified in vitro by sodium nitrite (NaNO₂). The silver-doped iron zinc oxide (Ag@Fe₃O₄/ZnO) is hydrothermally synthesized and characterized by analytical and spectroscopic techniques for the electrochemical sensing of methemoglobin via cyclic voltammetry (CV). Detection parameters such as concentration, pH, scan rate, electrochemical active surface area (ECSA), and electrochemical impedance spectroscopy (EIS) are optimized. The linear limit of detection for Ag@Fe₃O₄/ZnO is 0.17 µM. The stability is determined by 100 cycles of CV and chronoamperometry for 40 h. The serum samples of anemia patients with different hemoglobin levels (Hb) are analyzed using Ag@Fe₃O₄/ZnO modified biosensor. The sensor's stability, selectivity, and response suggest its use in methemoglobinemia monitoring.

Production and Inhibition of Acrylamide during Coffee Processing: A Literature Review

Coffee is the third-largest beverage with wide-scale production. It is consumed by a large number of people worldwide. However, acrylamide (AA) is produced during coffee processing, which seriously affects its quality and safety. Coffee beans are rich in asparagine and carbohydrates, which are precursors of the Maillard reaction and AA. AA produced during coffee processing increases the risk of damage to the nervous system, immune system, and genetic makeup of humans. Here, we briefly introduce the formation and harmful effects of AA during coffee processing, with a focus on the research progress of technologies to control or reduce AA generation at different processing stages. Our study aims to provide different strategies for inhibiting AA formation during coffee processing and investigate related inhibition mechanisms.

Silica Nanospheres Coated Silver Islands as an Effective Opto-Plasmonic SERS Active Platform for Rapid and Sensitive Detection of Prostate Cancer Biomarkers

The in vitro diagnostics of cancer are not represented well yet, but the need for early-stage detection is undeniable. In recent decades, surface-enhanced Raman spectroscopy (SERS) has emerged as an efficient, adaptable, and unique technique for the detection of cancer molecules in their early stages. Herein, we demonstrate an opto-plasmonic hybrid structure for sensitive detection of the prostate cancer biomarker sarcosine using silica nanospheres coated silver nano-islands as a facile and efficient SERS active substrate. The SERS active platform has been developed via thin (5-15 nm) deposition of silver islands using a simple and cost-effective Radio Frequency (RF) sputtering technique followed by the synthesis and decoration of silica nanospheres (~500 nm) synthesized via Stober's method. It is anticipated that the coupling of Whispering Gallery Modes and photonic nano-jets in SiO₂ nanospheres induce Localized Surface Plasmon Resonance (LSPR) in Ag nano-islands, which is responsible for the SERS enhancement. The as-fabricated SERS active platform shows a linear response in the physiological range (10 nM to 100 μM) and an extremely low limit of detection (LOD) of 1.76 nM with a correlation coefficient of 0.98 and enhancement factor ~2 × 10⁷. The findings suggest that our fabricated SERS platform could be potentially used for the rapid detection of bio-chemical traces with high sensitivity.

A Fast and Easy Probe Based on CMC/Eu (Ⅲ) Nanocomposites to Detect Acrylamide in Different Food Simulants Migrating from Food-Contacting Paper Materials

The residual acrylamide in food paper packaging can be transferred into water and food, which will cause harmful effects on human beings. In this paper, a rapid and easily available fluorescent probe based on carboxymethyl cellulose (CMC)/Eu (Ⅲ) nanocomposites was designed to detect the residue acrylamide with high sensibility. The probe could respond in 1 min. The concentration of acrylamide was linearly correlated to the fluorescence intensity of the probe at the emission wavelength of 615 nm in the concentration range of 0.1–100 μmol/L. The limit of detection (LOD) of the probe was 0.085 μg/L, which is lower than the guideline value of the European Union, the U.S. EPA, and the WHO. An experiment was performed to simulate the acrylamide migrating from food-contacting paper materials to different foods, including waterborne food, alcohol beverage, acidic food, and greasy food. The recoveries and RSDs of acrylamide in all samples indicated that the CMC/Eu (Ⅲ) fluorescent probe was efficient for acrylamide detection. The possible mechanism of the probe for acrylamide detection involved both dynamically quenching and static quenching by forming of non-fluorescent substances.

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.

Characterization of Polyphenol and Volatile Fractions of Californian-Style Black Olives and Innovative Application of E-nose for Acrylamide Determination

Californian-style black olives require a sterilization treatment that produces a carcinogenic contaminant, acrylamide. Thus, this compound was evaluated in two different olive cultivars using an electronic nose (E-nose). The sterilization intensity had a significant influence on the final phenol concentrations, acrylamide content, and volatile compounds. Increasing the sterilization intensity from 10 to 26 min (F0) reduced the phenol content, but it promoted acrylamide synthesis, leading to a wide range of this toxic substance. The Ester and phenol groups of volatile compounds decreased their content when the sterilization treatment increased; however, aldehyde and other volatile compound groups significantly increased their contents according to the thermal treatments. The compounds 4-ethenyl-pyridine, benzaldehyde, and 2,4-dimethyl-hexane are volatile compounds with unpleasant odours and demonstrated a high amount of influence on the differences found after the application of the thermal treatments. The “Manzanilla Cacereña” variety presented the highest amount of phenolic compounds and the lowest acrylamide content. Finally, it was found that acrylamide content is correlated with volatile compounds, which was determined using multiple linear regression analysis (R² = 0.9994). Furthermore, the aroma of table olives was analysed using an E-nose, and these results combined with Partial Least Square (PLS) were shown to be an accurate method (range to error ratio (RER) >10 and ratio of performance to deviation (RPD) >2.5) for the indirect quantification of this toxic substance.

Highly Sensitive Voltammetric Determination of Acrylamide Based on Ibuprofen Capped Mercury Nanoparticles

Highly stable, small-sized and evenly distributed solid mercury nanoparticles capped with ibuprofen (Ibu-HgNPs) were prepared via reduction with hydrazine and capped with ibuprofen as a stabilizing agent. Characterization of Ibu-HgNPs was carried out by UV-Vis spectrophotometry and transmission electron microscopy (TEM). The prepared Ibu-HgNPs were immobilized onto a glassy carbon electrode (GCE) and used for the first time as the sensing element for voltammetric determination of low concentrations of acrylamide (AA) in aqueous solutions. Various parameters such as the type of supporting electrolyte, voltammetric mode, frequency, deposition time, stirring rate and initial potential were optimized to obtain the highest peak current of AA. The sensor delivered the best results in combination with the square wave voltammetry (SWV) mode, with good repeatability (relative standard deviation (RSD) of 25 repetitions was 1.4% for 1000 ppb AA). The study further revealed that Ibu-HgNPs are strongly adhered to GCE and hence do not contaminate the environment even after several runs. The newly developed AA sensor provides linear calibration dependence in the range of 100-1300 ppb with an R2 value of 0.996 and limit of detection (LOD) of 8.5 ppb. Negligible interference was confirmed from several organic compounds, cations and anions. The developed sensor was successfully applied for AA determination in various types of environmental real water samples to prove its practical usefulness and applicability.

A Chemosensor Based on Gold Nanoparticles and Dithiothreitol (DTT) for Acrylamide Electroanalysis

Rapid and simple electroanalysis of acrylamide (ACR) was feasible by a gold electrode modified with gold nanoparticles (AuNPs) and dithiothreitol (DTT) with enhanced detection sensitivity and selectivity. The roughness of bare gold (Au) increased from 0.03 μm to 0.04 μm when it was decorated with AuNPs. The self-assembly between DTT and AuNPs resulted in a surface roughness of 0.09 μm. The DTT oxidation occurred at +0.92 V. The Au/AuNPs/DTT surface exhibited a surface roughness of 0.24 μm after its exposure to ACR with repeated analysis. SEM imaging illustrated the formation of a polymer layer on the Au/AuNPs/DTT surface. Surface plasmon resonance analysis confirmed the presence of AuNPs and DTT on the gold electrode and the binding of ACR to the electrode's active surface area. The peak area obtained by differential pulse voltammetry was inversely proportional to the ACR concentrations. The limit of detection (LOD) and the limit of quantitation (LOQ) were estimated to be 3.11 × 10-9 M and 1 × 10-8 M, respectively, with wide linearity ranging from 1 × 10-8 M to 1 × 10-3 M. The estimated levels of ACR in potato chips and coffee samples by the sensor were in agreement with those of high-performance liquid chromatography.

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

Acrylamide, a food processing contaminant with demonstrated genotoxicity, carcinogenicity, and reproductive toxicity, is largely present in numerous prominent and commonly consumed food products that are produced by thermal processing methods. Food regulatory bodies such as the U.S. Food and Drug Administration (U.S. FDA) and European Union Commission regulations have disseminated various acrylamide mitigation strategies in food processing practices. Hence, in the wake of such food and public health safety efforts, there is a rising demand for economic, rapid, and portable detection and quantification methods for these contaminants. Since conventional quantification techniques like liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) methods are expensive and have many drawbacks, sensing platforms with various transduction systems have become an efficient alternative tool for quantifying various target molecules in a wide variety of food samples. Therefore, this present review discusses in detail the state of robust, nanomaterials-based and other bio/chemical sensor fabrication techniques, the sensing mechanism, and the selective qualitative and quantitative measurement of acrylamide in various food materials. The discussed sensors use analytical measurements ranging from diverse and disparate optical, electrochemical, as well as piezoelectric methods. Further, discussions about challenges and also the potential development of the lab-on-chip applications for acrylamide detection and quantification are entailed at the end of this review.

Differential colorimetric nanobiosensor array as bioelectronic tongue for discrimination and quantitation of multiple foodborne carcinogens

Foodborne amides, specifically acrylamide, are vitally important for food safety and security, as they are the most common food toxicants and suspected human carcinogens. A facile and novel differential-based colorimetric nanobiosensor array composed of three surface-bioengineered gold nanoparticles (AuNPs) was developed for the rapid detection, differentiation, and quantification of acrylamide and six analogues. Diverse cross-reactive receptors demonstrated differential binding affinities toward target analytes, resulting in distinctive AuNP aggregation behaviors and distinguishable response patterns. The sensor array, integrated with principal component analysis and hierarchical cluster analysis, accurately discriminated foodborne amides based on their amine subgroups, International Agency for Research on Cancer (IARC) carcinogen classifications, and food additive types, even at ultra-low concentrations (500 pM). Additionally, the sensor array successfully differentiated non-targeted analytes by sweetener and food ingredients types with 100% correct classification. Partial least squares regression outcomes exhibited high correlation coefficients (R2 > 0.95). Thus, the sensor array has practical potential for food safety monitoring in the food and beverage industries.

Searching for conditions of protein self-assembly by protein crystallization screening method

The self-assembly of biomacromolecules is an extremely important process. It is potentially useful in the fields of life science and materials science. To carry out the study on the self-assembly of proteins, it is necessary to find out the suitable self-assembly conditions, which have always been a challenging task in practice. Inspired by the screening technique in the field of protein crystallization, we proposed using the same screening technique for seeking suitable protein self-assembly conditions. Based on this consideration, we selected 5 proteins (β-lactoglobulin, hemoglobin, pepsin, lysozyme, α-chymotrypsinogen (II) A) together with 5 screening kits (Index^TM, BML, Morpheus, JCSG, PEG/Ion Screen^TM) to investigate the performance of these crystallization screening techniques in order to discover new optimized conditions of protein self-assembly. The screens were all kept at 293 K for certain days, and were analyzed using optical microscope, scanning electron microscope, transmission electron microscope, atomic force microscope, fluorescence microscope, and atomic absorption spectroscope. The results demonstrated that the method of protein crystallization screening can be successfully applied in the screening of self-assembly conditions. This method is fast, high throughput, and easily implemented in an automated system, with a low protein consumption feature. These results suggested that such strategy can be applied to finding new conditions or forms in routine research of protein self-assembly. KEY POINTS: • Protein crystallization screening method is successfully applied in the screening of self-assembly conditions. • This screening method can be applied on various kinds of proteins and possess a feature of low protein consumption. • This screening method is fast, high throughput, and easily implemented in an automated system.

Development of an Isotope Dilution UHPLC-QqQ-MS/MS-Based Method for Simultaneous Determination of Typical Advanced Glycation End Products and Acrylamide in Baked and Fried Foods

In this work, a stable isotope dilution ultrahigh-performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) method was developed and validated for simultaneous determination of N^ε-(carboxymethyl)lysine (CML), N^ε-(carboxyethyl)lysine (CEL), and acrylamide (AA) in baked and fried foods. Ground food samples were extracted with acetone followed by two parallel assays. In assay A, a cleanup procedure based on dispersive solid-phase extraction was conducted for AA, free CML, and CEL analysis using the supernatant. In assay B, a multistep process including reduction, protein precipitation, acid hydrolysis, and solid-phase extraction was conducted for bound CML and CEL analysis using precipitation. The developed method was validated in terms of linearity, sensitivity (limit of detection, LOD; limit of quantitation, LOQ), accuracy, and precision. The results showed that the method had a wide linear range (0.25-500 ng/mL for CML and CEL, 0.5-500 ng/mL for AA), low LOD and LOQ (0.47-0.94 and 1.52-1.91 μg/kg, respectively), and good linearity (R² > 0.999). The recovery test on baby biscuit and French fries samples showed the recovery rates of 90.2-108.3% for CML, 89.0-106.1% for CEL, and 94.5-112.3% for AA with satisfactory precision (relative standard deviation (RSD) < 10%). Finally, the developed method was successfully applied to 11 baked and fried food samples, and total CML, CEL, and AA contents varied in the ranges of 4.07-35.88 mg/kg, 1.99-14.49 mg/kg, and 5.56-506.64 μg/kg, respectively. Therefore, the isotope dilution UHPLC-QqQ-MS/MS method developed herein is promising for routine analysis of CML, CEL, and AA in baked and fried foods.

Molecularly imprinted photoelectrochemical sensing based on ZnO/polypyrrole nanocomposites for acrylamide detection

A highly sensitive quenching molecular imprinting (MIP) photoelectrochemical (PEC) sensor was proposed to detect acrylamide (AM) by using the photoactive composite of ZnO and polypyrrole (PPy) as the PEC signal probe. ZnO, with high electron mobility, excellent chemical and thermal stability as well as good biocompatibility, was selected as the photoelectrically active material. A polypyrrole film was formed on the nanodisk ZnO by electrochemical polymerization, and the recognition site of AM was left on the surface of the PPy film by elution, enabling the specific detection of AM. The transfer of electrons will be hindered when AM is adsorbed on the ZnO/PPy nanocomposites surface, which results in the decrease of photocurrent signal. The proposed molecularly imprinted PEC sensor exhibits significant detection performance of AM in the range of 10-1 M-2.5 × 10-9 M with a LOD of 2.147 × 10-9 M (S/N = 3). The use of photoelectrochemical technology combined with molecular imprinting technology enables the PEC sensor to have excellent selectivity, superior repeatability, preferable stability, low cost, and easy construction, providing a new method for the detection of AM. The high recovery rate in the detection of real samples of potato chips and biscuits indicates that the proposed PEC sensor has potential in monitoring the emerging food safety risks.

Review of Research into the Determination of Acrylamide in Foods

Acrylamide (AA) is produced by high-temperature processing of high carbohydrate foods, such as frying and baking, and has been proved to be carcinogenic. Because of its potential carcinogenicity, it is very important to detect the content of AA in foods. In this paper, the conventional instrumental analysis methods of AA in food and the new rapid immunoassay and sensor detection are reviewed, and the advantages and disadvantages of various analysis technologies are compared, in order to provide new ideas for the development of more efficient and practical analysis methods and detection equipment.