Quasi-spherical silver nanoparticles for human prolactin detection by surface-enhanced Raman spectroscopy

Area of Science:

• Biochemistry and Spectroscopy
• Analytical Chemistry

Background:

• Prolactin is a polypeptide hormone crucial for lactation, with normal serum levels varying by sex and pregnancy status.
• Conventional immunoassay techniques for prolactin detection can be prone to errors in certain clinical scenarios.
• Surface-enhanced Raman spectroscopy (SERS) offers a rapid and reproducible method for protein spectrum analysis, but human prolactin's SERS spectrum at physiological concentrations requires further characterization.

Purpose of the Study:

• To characterize the Raman spectrum of human prolactin at physiological concentrations.
• To utilize silver nanoparticles (AgNPs) as a substrate for SERS analysis of human prolactin.
• To establish a method for detecting human prolactin's spectral signature at low concentrations.

Main Methods:

• Synthesis of quasi-spherical silver nanoparticles (AgNPs) via chemical methods.
• Preparation of serial dilutions of human prolactin.
• Acquisition of Raman and SERS spectra using AgNPs as the substrate, analyzing mixtures of prolactin and AgNPs.

Main Results:

• The SERS spectrum of human prolactin was successfully obtained down to concentrations of 0.1 ng/mL.
• The obtained spectra exhibited characteristic bands related to aromatic amino acid side chains and alpha-helical structures within prolactin.
• The SERS technique demonstrated sensitivity to prolactin's primary and secondary structural features.

Conclusions:

• Quasi-spherical silver nanoparticles serve as an effective SERS substrate for human prolactin analysis.
• The study successfully determined the Raman spectrum of human prolactin at physiological concentrations.
• SERS provides a viable method for characterizing prolactin's spectral properties, potentially aiding in diagnostics.