pH-Based Detection of Target Analytes in Diluted Serum Samples Using Surface Plasmon Resonance Immunosensor

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biosensing

Background:

• Heterogeneous immunosensors require enhanced capture efficiencies for detecting low concentrations of target antigens in complex serum matrices.
• Solution pH is a critical parameter influencing the capture of charged target proteins in serum samples.

Purpose of the Study:

• To investigate the effect of pH optimization on the capture of prostate-specific antigens (PSA) in mixed-analyte systems.
• To evaluate interference effects from non-specific proteins in serum samples.
• To develop a pH-tuned heterogeneous immunosensor for sensitive biomarker detection.

Main Methods:

• Utilized surface plasmon resonance spectroscopy to study PSA capture in mixed-analyte systems.
• Varied solution pH to optimize target analyte capture efficiency.
• Assessed interference from non-specific proteins by adjusting protein ratios.
• Tested the developed immunosensor with PSA-spiked rabbit serum samples.

Main Results:

• Optimized solution pH significantly improved PSA capture efficiency in the presence of interfering proteins.
• Successfully detected PSA in serum samples diluted 100-fold, with interfering proteins present at ~66 times the PSA concentration.
• Demonstrated the feasibility of detecting low antigen concentrations in complex biological fluids.

Conclusions:

• pH tuning is a viable strategy to enhance heterogeneous immunosensor performance for biomarker detection in diluted serum.
• The proposed immunosensor design offers a promising approach for sensitive and specific detection of disease biomarkers in complex biological samples.
• This method can be broadly applied to detect various target analytes in serum by adjusting solution pH.