Quantification of chromogranin A using a surface plasmon resonance-based biosensor.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biochemistry

Background:

• Chromogranin A (CgA) is a crucial biomarker for neuroendocrine tumors and other conditions.
• Existing CgA detection methods are costly, time-consuming, and lack reproducibility.
• There is a need for a more efficient and reliable CgA quantification technique.

Purpose of the Study:

• To validate surface plasmon resonance (SPR) as a method for quantifying CgA.
• To optimize SPR conditions for sensitive and reproducible CgA detection.
• To compare the performance of SPR with traditional methods like ELISA.

Main Methods:

• Immobilization of CgA antibody (CgA-Ab) onto a CM5 sensor chip (CgA-Ab-CM5).
• Optimization of binding (240 s, 30 μL/min) and regeneration (pH 1.75) conditions.
• Quantification of varying CgA concentrations using the optimized SPR assay.

Main Results:

• The SPR method achieved a linear detection range of 0.2-187 ng/mL for CgA.
• This range is significantly broader and more sensitive than the 23.4-187 ng/mL range of ELISA.
• The CgA-Ab-CM5 chip demonstrated high reproducibility over 300 binding-regeneration cycles.

Conclusions:

• SPR is a highly sensitive and reliable technique for real-time CgA quantification.
• The validated SPR-based CgA-Ab-CM5 chip offers a significant improvement over conventional methods.
• This method holds promise for improved diagnostics and monitoring of CgA-related diseases.