BAM-developed LFIA test cassettes provide quantitative results on Bisphenol A burden from polymer coatings
Source: BAM, division Environmental Analysis
Bisphenol A (BPA) is an important basic chemical used in the production of certain plastics, for example polycarbonate, and in coatings. Studies indicate reproductive toxicity and endocrine disrupting effects of BPA. To protect the consumer, it is desirable to develop a simple, sensitive, inexpensive and rapid method that can be ideally used on-site. The so-called lateral flow immunoassay (LFIA), recently used by billions of people in the SARS-CoV-2 antigen rapid tests, has this potential. In order to meet all criteria, especially regarding sensitivity, these assays need to be carefully optimised. To achieve higher sensitivity, we first replaced the gold nanoparticles ("nanogold", responsible for the formation of the red lines) with dyed latex microparticles, resulting in blue, highly visible lines. The sensitivity of the test was further improved by non-contact printing of dot grids, which nevertheless appear as control and test lines, with careful parameter optimisation. The test results could be evaluated visually within 10 minutes at a visual cut-off of 10 nanograms per millilitre of test solution. It should be noted that lateral flow immunoassays for small molecules use a competitive format and here the absence of the test line indicates that the cut-off level has been exceeded.
Alternatively, to obtain not only a yes/no answer but a quantitative result, photos were taken with a smartphone and a software-based image analysis was performed. The intensity values can be used to create a calibration via calibrators, which enabled a detection limit of 0.14 nanograms per millilitre of test solution.
Development of a Lateral Flow Immunoassay (LFIA) to Screen for the Release of the Endocrine Disruptor Bisphenol A from Polymer Materials and Products
Anna Raysyan and Rudolf J. Schneider
published in Biosensors, Vol. 11, issue 7, page 231, 2021
BAM, division Environmental Analysis