Competitive immunoassay for vancomycin using capillary electrophoresis with laser-induced fluorescence detection

Area of Science:

• Analytical Chemistry
• Biochemistry

Background:

• Vancomycin is a critical antibiotic for treating serious infections.
• Accurate and sensitive monitoring of vancomycin levels is essential for therapeutic efficacy and minimizing toxicity.
• Existing immunoassays may require significant reagent volumes and processing time.

Purpose of the Study:

• To develop a novel, highly sensitive immunoassay for vancomycin quantification.
• To utilize capillary electrophoresis (CE) coupled with laser-induced fluorescence polarization (LIFP) for enhanced detection.
• To evaluate the method's performance using clinical samples and compare it to a standard assay.

Main Methods:

• Development of a competitive immunoassay format utilizing CE.
• Employing a Tris-glycine running buffer for rapid separation (<4 min) of antibody-bound and unbound fluorescent probes.
• Detection via laser-induced fluorescence polarization (LIFP) for simultaneous intensity and polarization measurement.

Main Results:

• Successful separation and detection of vancomycin-antibody complexes.
• Achieved a minimum detectable concentration of 0.98 ng/mL (1.1 fg vancomycin).
• Demonstrated excellent correlation with a standard latex particle immunoassay in clinical samples.
• Required only 1/10th of the reagents compared to the standard method.

Conclusions:

• The developed CE-LIFP immunoassay is a sensitive, rapid, and reagent-efficient method for vancomycin quantification.
• This technique offers a viable alternative to conventional immunoassays for therapeutic drug monitoring.
• The method's high sensitivity and correlation with existing assays support its clinical applicability.