Immunochromatography Detection of Ricin in Environmental and Biological Samples

Ricin has been considered as a potential agent of biological warfare or terrorist attack. This work is aimed to develop and evaluate a rapid test strip for the assay of ricin in environmental and biological samples. Two specific antibodies were used respectively as the capture antibody (Mab 4C13) coated on a nitrocellulose membrane and the tracing antibody (MAb 3D74) labeled with colloidal gold. The immunochromatography strips were tested to detect ricin in porridge, salted vegetable, water and other drinks. The detection could be finished within fifteen minutes and its sensitivity was at 10 ng/ml of ricin in water. When no ricin control samples were tested in parallel, some kind of drinks, such as Sprite and Coca cola showed false positive bands even without toxin pollution, indicating the negative control is essential to avoid possible false positive results. The strips could give positive signals after loading human serum sample mixed with 25 ng ml^-1 of ricin in vitro. When rats were intramuscularly treated with 100 ug kg^-1 of ricin, the residual ricin in the serum samples could be successfully detected by the strips even at 24 h after intoxication. The immunochromatography test strip is a useful tool to check the possible pollution of ricin in enviromental samples such as drink and food, and even to detect the residual toxin in human serum before victim developing intoxication symptoms.