Development of a Fluorescence-Linked Immunosorbent Assay for Baicalin

Area of Science:

• Biochemistry
• Analytical Chemistry
• Pharmacology

Background:

• Baicalin (BAL) is a key compound in traditional medicine.
• Previous pharmacokinetic studies of BAL utilized an indirect competitive enzyme-linked immunosorbent assay (icELISA).
• A need exists for more sensitive and efficient methods for BAL detection.

Purpose of the Study:

• To develop and characterize an indirect competitive fluorescence-linked immunosorbent assay (icFLISA) for baicalin (BAL).
• To compare the performance of the icFLISA with the previously established icELISA for BAL detection.
• To establish a sensitive method for BAL quantification in medicinal and biological samples.

Main Methods:

• Purification of anti-baicalin (BAL) monoclonal antibody (MAb).
• Labeling of the purified MAb with fluorescein isothiocyanate (FITC).
• Development and validation of the indirect competitive fluorescence-linked immunosorbent assay (icFLISA) for BAL detection.

Main Results:

• The icFLISA demonstrated an effective BAL measurement range of 6.4 ng/mL to 500 μg/mL (R(2)=0.997).
• Assay precision and repeatability were excellent, with relative standard deviations (RSDs) below 10%.
• The icFLISA exhibited a 390-fold larger linear range and a 2-fold lower limit of detection (LOD) compared to icELISA.

Conclusions:

• The developed icFLISA is a simple, rapid, and sensitive method for detecting baicalin (BAL).
• This assay offers significant improvements in linear range and sensitivity over the previous icELISA.
• The icFLISA is a valuable tool for quantitative analysis of BAL in medicines and facilitates in vivo visualization studies.