Development Of The Immunochromatographic Test Strips For Rapid Detection Of Aristolochic Acid Ⅰ And T-2 Toxin

Aristolochic acid I(AA-I)and T-2 toxin(T-2)are hazardous small molecule toxins with carcinogenicity and cytotoxicity.AA-I is mainly found in herbs such as Aristolochia and asarum,and T-2 toxin mainly contaminates cereals such as wheat and maize.Detection of AA-I in herbal medicine and T-2 toxins in cereals is of great significance for protecting people’s health.At present,large-scale instruments such as liquid chromatography(LC)are commonly used to detect AA-I,T-2 toxins,and such methods often require professional operation and are time-consuming.The immunochromatographic test strip(ICS)has the advantages of high specificity as well as short time consuming,while the conventional gold nanoparticles-based ICS has limited sensitivity for detecting AA-I and T-2 toxins.Therefore,ICSs were developed based on signal amplification method as well as selenium nanoparticles labeling method to improve the sensitivity of ICS for detecting AA-I in herbal medicines and T-2 toxin in cereals.First,spherical gold nanoparticles with different particle sizes were prepared by the method of reducing chloroauric acid via trisodium citrate,and the combination method of gold nanoparticles with particle size of 20 nm and 30 nm was selected,and the smaller gold nanoparticles(20 nm)labeled monoclonal antibodies were conjugated with the larger gold nanoparticles(30 nm)labeled secondary antibodies to establish the signal amplification mode.Based on the mode,the process parameters of the signal amplified ICS for rapid detecting AA-I and T-2 toxin were optimized,and the signal amplified ICSs with sensitivity of 1 ng/m L were successfully prepared.The detection time of both ICSs was 10 min.Next,spherical,homogeneously dispersed,and stable selenium nanoparticles were successfully synthesized by reduction of selenite with vitamin C under conditions in which PEG and SDS were used as stabilizing agents.Selenium nanoparticles-based ICS with a sensitivity of 0.25 ng/m L for detecting T-2 toxin was prepared by labeling monoclonal antibodies with selenium nanoparticles as the chromogenic material.The test strip could complete the test within 10 min.In addition,the specificity and stability of the prepared ICSs were evaluated.None of the three ICSs cross reacted with small molecule toxins such as aristolochic acid II(AA-II),deoxynivalenol(DON)and zearalenone(ZEN),and they still had comparable stability to the newly prepared test strips after being stored at 37 ℃ for 2 weeks or 25 ℃at constant temperature for 3 months,indicating that the prepared test strips had good specificity and stability.Finally,AA-I and T-2 toxins in 20 herbal medicine samples and 24 cereal samples were rapidly detected by signal amplified ICS and selenium nanoparticles ICS,respectively,and verified by HPLC and ELISA.The results showed that the obtained results were generally consistent between the methods in the detection of AA-I and T-2 toxins from real samples.Therefore,both the signal amplified ICSs for AA-I,T-2toxin and the selenium nanoparticles ICS for T-2 toxin could be used in the detection of real samples.