Development Of A Rapid Detection Technology Of A Strip Based On Aptamers In The Detection Of Aflatoxin B1

A novel rapid detection technology of a strip based on aptamers was developed and used for the first time in the detection of aflatoxin B1 in water.The realization of this technique is based on the competition of aflatoxin B1 and DNA probes.Aptamers are artificially synthesized single-stranded DNA or RNA,which can bind specifically to various substances and have strong specificity.Using aptamers instead of antigens and antibodies in traditional colloidal gold lateral flow immunochromatography can make strip rapid detection technology has a wider range of applications and higher sensitivity;nanogold particles become red when they are gathered in large quantities and are visible to the naked eye,which means that real-time detection of test strips can be realized.(1)Preparation of nanogold particles and self-assembly of nanogold particles and aptamers.In this experiment,nanogold particles were prepared by Frens method.The rotational speed,reaction time and the amount of reducing agent were investigated.The characteristics of nanogold particles were characterized by means of UV and transmission electron microscopy.The aptamer of the nucleic acid terminal is modified with a thiol group,and the thiol group can form a covalent bond with the nanogold particles.When self-assembly of the nano gold particles and the aptamer utilizes trisodiμM citrate and adjusts the pH,the self-assembly time is used from the chlorine.The self-assembly time was shortened to 3-4 hours for 1-2 days,and the amount of the aptamer on the surface of the nanogold particles was about 7 wt%using thermogravimetric analysis.(2)The test strip optimizes and detects aflatoxin B1.This experiment examined the types of nanogold-aptamer additions,sealants,nitrocellulose membranes,and streptavidin,and measured the absorbance using an immunochromatographic reader to determine the visual limit of detection aflatoxin B1 as 10 ng/mL,the limit of detection the immunochromatographic reader was 1.05 ng/mL,and the linear range was 1-50000 ng/mL.The recoveries of spiked samples ranged from 107.26%to 116.59%with relative standard deviations ranging from 2.95%to 4.73%.At the same time,the structural analogs of aflatoxin B1 were selected to verify the specificity of the strip,indicating that this method can be used to detect aflatoxin B1 in actual water samples.Finally,the interaction between aflatoxin B1 and aptamers was qualitatively investigated by circular dichroism.In this experiment,a test strip rapid detection technology based on aptamers provided a lower detection limit and a wider detection range for the detection of aflatoxin B1 in water,which facilitates faster real-time sample detection.Moreover,it provided the method basis for the detection of aflatoxin B1 in different samples.