Label-Free Aptasensors for the Detection of Mycotoxins

Abstract

Various methodologies have been reported in the literature for the qualitative and quantitative monitoring of mycotoxins in food and feed samples. Based on their enhanced specificity, selectivity and versatility, bio-affinity assays have inspired many researchers to develop sensors by exploring bio-recognition phenomena. However, a significant problem in the fabrication of these devices is that most of the biomolecules do not generate an easily measurable signal upon binding to the target analytes, and signal-generating labels are required to perform the measurements. In this context, aptamers have been emerged as a potential and attractive bio-recognition element to design label-free aptasensors for various target analytes. Contrary to other bioreceptor-based approaches, the aptamer-based assays rely on antigen binding-induced conformational changes or oligomerization states rather than binding-assisted changes in adsorbed mass or charge. This review will focus on current designs in label-free conformational switchable design strategies, with a particular focus on applications in the detection of mycotoxins.

Detection Methods for Aflatoxin M1 in Dairy Products

“…The difference of this sensor is in the biological recognition element, which is an aptamer instead of an antibody. The aptamer consists of a synthetic oligonucleotide ligand (either single stranded DNA (ssDNA) or RNA), generally comprising less than 80 nucleotides with a size lower than 25 kDa, and is known to exhibit high specificity and strong binding affinity [67,[69][70][71]. In an aptasensor, the aptamer recognizes the molecular target against which it was previously selected in vitro.…”

Future Trends for In Situ Monitoring of Polycyclic Aromatic Hydrocarbons in Water Sources: The Role of Immunosensing Techniques

“…The advantages of these immunosensors in comparison to traditional PAH detection methods like gas chromatography-mass spectrometry (GC-MS) are several, including miniaturization of instrumental devices. They also need minimal organic compounds, small test samples, little use of organic solvents, and they do not result in extensive cleaning due to potential contamination [75]. Also, the technique makes it possible to analyze many samples at the same time, and in situ analysis of environmental pollutant concentrations in a sample [76,77].…”

A Bottom-Up Approach for Developing Aptasensors for Abused Drugs: Biosensors in Forensics

“…There are several methods established for immobilization of the aptamers, and all are rooted from the same principles applied for the immobilization of DNA-based biomolecules [111]. Exploited in the literature, according to the abundancy, the techniques used for immobilization is classified as follows: direct attachment to gold, covalent attachment to functionalized surfaces, and bio coatings [109,110,112,113]. Direct attachment to gold substrates (e.g., electrodes, nanoparticles) is performed via chemisorption of thiol modified aptamers onto gold and has many advantages, such as the ease of immobilization, the ability to form a monolayer, the stability of the gold surfaces, high affinity to thiol-modified substances, and commercial availability [114].…”