Detection of alkaline phosphatase using surface-enhanced Raman spectroscopy

Area of Science:

• Analytical Chemistry
• Biochemistry
• Nanotechnology

Background:

• Alkaline phosphatase (ALP) is a crucial enzyme in various biological processes.
• Sensitive detection methods for ALP are essential for diagnostics and research.
• Existing techniques often lack the sensitivity required for ultralow concentration analysis.

Purpose of the Study:

• To develop a novel, highly sensitive method for detecting alkaline phosphatase (ALP) activity.
• To utilize surface-enhanced Raman scattering (SERS) with gold nanoparticles for ALP detection.
• To establish a new SERS-based approach for ultralow concentration enzyme activity measurement.

Main Methods:

• Employed gold nanoparticles as the SERS substrate.
• Utilized 5-bromo-4-chloro-3-indolyl phosphate (BCIP) as the ALP enzyme substrate.
• Analyzed the SERS signal generated by indigo dye derivatives from BCIP hydrolysis.

Main Results:

• Achieved detection of ALP at ultralow concentrations of approximately 4 x 10(-15) M.
• Demonstrated single-molecule level detection of ALP activity.
• Successfully detected surface-immobilized avidin with a detection limit of 10 ng/mL.

Conclusions:

• The developed SERS technique provides unprecedented sensitivity for ALP detection.
• This method enables the detection of both free and labeled ALP as a Raman probe.
• The SERS approach is applicable to enzyme immunoassays, immunoblotting, and DNA hybridization assays.