Question

We are trying to design an aptamer-based lateral flow strip biosensor to detect Ochratocin A in wheat samples.

what is the problem scope?

technical review?

design requirements?

Answer 1

Ans:

Aptamer-based lateral flow strip biosensor to detect Ochratocin A in wheat samples

What is the problem scope?

The food contaminats such as toxins and other chemicals may cause serious health risk hence there detection is major task.

Ochratoxin A (OTA) is a mycotoxin and produced by Aspergillus and Penicillium spp. This toxin occurs in cereal grains, spices, coffee beans and other types of cereals. OTA is well documented toxin for animals and humans. It is suspected to be a carcinogen in humans. Its detection in wheat therefore can be a good preventive measure to avoid carcinogen exposure to human body.

Technical review:

Aptamers are single stranded nucleic acid oligomers. They do possess diverse conformational shapes and these shapes help in recognition and binding of respective target molecules. Aptamers can be easily chemically modified and there shelf life is also long, due to these reasons aptamer based detectors or sensors are of biological importance.

The lateral flow strip make use of later flow assay (LFA) principal. LFA is a paper-based platform and can be used to detect as well as quantify various analytes in a complex mixture within 5-30 minutes.

The overall work flow or pictorial representation of LFA is as follows;

here in this case instead of blood sample, suspected wheat sample is used for detection of ochratocin A.

Design requirements and how it works:

The LFA strip or aptamer based lateral flow strip biosensor basically comprised of multiple overlapping membranes which is fixed on support card that provides certain stabilization. Hence the main requirement for such biosensor is stabilzation card which carries immobilized chemical or shape of aptamer which capture Ochratocin A. The assay work in following manner;

The solution or wheat sample is applied on to the sample pad. From its point of entry the sample flows laterally via capillary action towards conjugation pad where fluid rehydrates a detection lable which is composed of recognition element coupled to a reporter molecule like gold nano particles(AuNPs).This gold nano particle or aptamers can form complex with target molecule. The supporting pad on which aptamers are imobilized or attached can be a nitrocellulose membrane.