A surface plasmon resonance sensor for substance P using gold-modified calmodulin and melittin

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Neuroscience

Background:

• Substance P (SP) is a neuropeptide involved in various physiological processes.
• Accurate quantification of SP is crucial for understanding neurological functions and diseases.
• Existing methods for SP detection may lack sensitivity or specificity.

Purpose of the Study:

• To develop and characterize a novel Surface Plasmon Resonance (SPR) biosensor for the sensitive and selective quantification of Substance P (SP).
• To utilize Au colloid-modified calmodulin (Au-CaM) for enhanced SPR signal detection.
• To demonstrate the sensor's capability for quantifying SP in complex biological matrices like mouse brain extracts.

Main Methods:

• Immobilization of melittin on a carboxymethylated dextran-coated sensor chip.
• Modification of calmodulin with streptavidin Au colloids via amine coupling.
• Quantification of SP using an inhibition assay based on SPR signal changes.
• Assessment of sensor selectivity against related peptides and neurotransmitters.

Main Results:

• The Au-CaM modification significantly enhanced the SPR signal for SP detection.
• The developed SPR biosensor achieved a lower detection limit ten times superior to unmodified calmodulin.
• The sensor demonstrated high selectivity for SP over neurokinin A, neurokinin B, and various neurotransmitters.

Conclusions:

• The Au-CaM SPR biosensor provides a sensitive and selective platform for Substance P quantification.
• This method offers improved performance compared to sensors using unmodified calmodulin.
• The biosensor shows potential for application in analyzing SP levels in biological samples, such as brain extracts.