Development of Fluorescence-Linked Immunosorbent Assay for Icariin

Area of Science:

• Natural Product Analysis
• Biochemical Assays
• Immunochemistry

Background:

• Traditional Chinese medicine and natural product analysis require efficient detection methods.
• Icariin (ICA) is a key compound in traditional Chinese medicine with therapeutic potential.
• Existing assay methods for ICA can be time-consuming and less sensitive.

Purpose of the Study:

• To develop a faster, simpler, and more sensitive fluorescent immunoassay for icariin (ICA) detection.
• To establish an indirect competitive fluorescence-linked immunosorbent assay (icFLISA) for ICA.
• To enable in vivo visualization and pharmacokinetic studies of ICA.

Main Methods:

• Purification of an ICA-specific monoclonal antibody (MAb).
• Labeling the MAb with rhodamine B isothiocyanate (RBITC).
• Development and validation of an indirect competitive fluorescence-linked immunosorbent assay (icFLISA) using the labeled MAb.

Main Results:

• The RBITC-labeled MAb demonstrated high specificity for ICA.
• The icFLISA achieved an effective ICA measurement range of 1.28 ng/mL to 20 μg/mL (R² = 0.9946).
• The assay exhibited excellent intra- and inter-assay precision (RSD < 10%) and offered a 20-fold wider linear range and 10-fold lower detection limit than ELISA.

Conclusions:

• The developed icFLISA is a simple, rapid, and sensitive method for detecting ICA.
• This assay provides significant improvements over traditional methods like ELISA.
• The icFLISA is suitable for quantifying ICA in biological samples and facilitating in vivo research.