Aptamer-Based Analysis: A Promising Alternative for Food Safety Control

Abstract

Ensuring food safety is nowadays a top priority of authorities and professional players in the food supply chain. One of the key challenges to determine the safety of food and guarantee a high level of consumer protection is the availability of fast, sensitive and reliable analytical methods to identify specific hazards associated to food before they become a health problem. The limitations of existing methods have encouraged the development of new technologies, among them biosensors. Success in biosensor design depends largely on the development of novel receptors with enhanced affinity to the target, while being stable and economical. Aptamers fulfill these characteristics, and thus have surfaced as promising alternatives to natural receptors. This Review describes analytical strategies developed so far using aptamers for the control of pathogens, allergens, adulterants, toxins and other forbidden contaminants to ensure food safety. The main progresses to date are presented, highlighting potential prospects for the future.

Sensitive gluten determination in gluten-free foods by an electrochemical aptamer-based assay

“…Conversely, we registered a maximum signal value of 4.7± 0.1 µA and 3.6±0.1 µA for Gli 4 and Gli 1, respectively at this aptamer concentration. These results are consistent with the specific interaction of both aptamers with the immobilized peptide and a higher affinity for the aptamer Gli 4 [15]. Therefore, the best performance in terms of sensitivity is obtained employing 0.06 mg mL -1 of the modified beads and 250 nM aptamer, in the presence of 1.2% ethanol.…”

“…We chose a competitive assay format, well suited to detect both intact protein and small protein fragments, using two previously selected aptamers targeting the immunotoxic α2-gliadin fragment, 33-mer [15]. Magnetic microparticles are employed as support for the sensing phase to take advantage of the efficient magnetic separation offered by this platform, which facilitates subsequent exhaustive washing steps thus minimizing major problems associated with non-specific interactions.…”

“…In a previous study, hordein content in gluten was comparatively assessed using ELISA and MS [28]. This study reveals significant differences between both methods, showing that 10% of the tested beers give ELISA gluten contents below the limit 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 F o r P e e r R e v i e w 17 of quantification but near average hordein content by MS. Our assay, using an aptamer that detects hordeins [15], could be an alternative for this kind of samples.…”

“…To overcome this drawback, competitive immunoassays have been developed based on the R5 antibody and using as calibration standard gliadin [4] or a mixture of whole protein and hydrolysed fragments [13] or on the G12 antibody and tracing the calibration curve using whole gliadin [11]. However, neither the sandwich assays, not the competitive ones are fully compatible with the With the aim of solving this problem, we have recently obtained a panel of aptamers for specific binding to gliadin [15]. These non-protein receptors, obtained against one of the main immunogenic gluten peptides known as 33-mer [7], are able to bind not only the peptide used as target for selection but also the whole protein and homologous ones in rye, barley and oats, suggesting they might serve as viable receptors for the detection of gluten in foods at concentrations below the 20 ppm threshold proposed by the Codex Alimentarius Commission.…”

Gliadins in Foods and the Electronic Tongue

“…Food allergy is an adverse, abnormal immune-mediated reaction to a certain food or food ingredient that appears in susceptible individuals, often requiring a strict avoidance of their ingestion (Amaya-González et al, 2013). Sometimes, people exhibit food sensitivity, including intolerance that is a nonimmune-mediated reaction.…”