Development of a Simple, Fast, and Quantitative Lateral Flow Immunochromatographic Strip for Folic Acid
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Folic acid (FA) is an important B vitamin naturally found in foods and also used in dietary supplements and food fortification. To monitor FA content is important to guarantee food quality and also to prevent its abuse in dietary supplements. In this work, we developed a simple and robust lateral flow immunochromatographic assay (ICA) for the routine screening of FA in food samples. FA was conjugated to carrier protein as immunogen and used to produce specific polyclonal antibody (pAb). The pAb was conjugated with gold nanoparticle and used to develop a lateral flow ICA. After the careful optimization of ICA conditions, the assay showed an IC50 of 51.8 ng mL−1 and linear range from 23.4 to 114.5 ng mL−1 for FA in assay buffer, with the assist of a DY6510 strip reader within 8 min. Using milk powder as a matrix model, after a 15-fold dilution to eliminate matrix effect, the ICA showed intra-assay recoveries from 94.2 to 107.0% with coefficient of variance (CV) below 15% and inter-assay recoveries from 91.4% to 111.3% with CV below 18%. Good agreement was obtained between the results of ICA and ciELISA and standard HPLC. It is an ideal screening tool for the fast monitoring of FA in a simple, fast, and low-cost manner.
KeywordsFolic acid Polyclonal antibody Immunochromatographic assay Quantitative detection
Compliance with Ethical Standards
This work was supported by the Guangdong Natural Science Funds for Distinguished Young Scholar (2014A030306026), Guangdong Special Support Program (2014TQ01N109), and Guangdong Young Teachers Program on Higher Education (Y920/4026).
Conflict of Interest
Zu-Pei Liang declares that he has no conflict of interest. Wu-Zu Ha declares that he has no conflict of interest. Zhi-Li Xiao declares that he has no conflict of interest. Hong-Tao Lei declares that he has no conflict of interest. Yu-Dong Shen declares that he has no conflict of interest. Yuan-Ming Sun declares that he has no conflict of interest. Hong Wang declares that he has no conflict of interest. Jin-Yi Yang declares that she has no conflict of interest. Zhen-Lin Xu declares that she has no conflict of interest.
All institutional and national guidelines for the care and use of laboratory animals were followed.
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