An SPR imaging immunosensor for leptin determination in blood plasma

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Immunosensing

Background:

• Leptin is a crucial hormone regulating feeding behavior and energy balance.
• Accurate leptin determination is vital for understanding metabolic disorders.
• Existing methods like ELISA can be time-consuming and complex.

Purpose of the Study:

• To develop and validate a specific SPRi immunosensor for quantifying leptin in human blood plasma.
• To establish the analytical performance characteristics of the developed immunosensor.
• To compare the SPRi method with ELISA for leptin determination.

Main Methods:

• Immobilization of rabbit anti-leptin antibodies on a gold chip using a cysteamine linker and EDC/NHS protocol.
• Utilizing non-fluidic array Surface Plasmon Resonance imaging (SPRi) for signal detection.
• Optimization of assay conditions to achieve desired sensitivity and linearity.

Main Results:

• The SPRi immunosensor demonstrated a linear response range from 0.23 to 5 ng mL^-1.
• Achieved a Limit of Detection (LOD) of 0.07 ng mL^-1 and a Limit of Quantitation (LOQ) of 0.23 ng mL^-1.
• Validation studies showed high correlation (Pearson's r=0.991) with ELISA and accurate recovery rates (97-110%).

Conclusions:

• The developed SPRi immunosensor provides a direct, rapid, and simplified method for leptin analysis in plasma.
• This technology holds promise as a valuable tool for clinical diagnostics and research, particularly in studies of malnutrition.
• The SPRi method significantly outperforms ELISA in terms of speed and simplicity.