PlQC based highly sensitive and reproducible novel SERS active substrate for biomolecule detection with high...

Area of Science:

• Nanotechnology
• Spectroscopy
• Biomolecular Sensing

Background:

• Surface-enhanced Raman spectroscopy (SERS) is a sensitive technique for detecting biomolecules.
• Existing SERS substrates face challenges in uniformity, sensitivity, and specificity.
• Label-free detection methods are desirable for biomolecule analysis.

Purpose of the Study:

• To develop a novel, highly sensitive, uniform, and stable SERS substrate.
• To demonstrate the label-free detection of cotinine, a biomarker for nicotine exposure.
• To evaluate the suitability of the developed substrate for analyzing complex biological samples.

Main Methods:

• Fabrication of plasmonic quasicrystal (PlQC) structures.
• Characterization of PlQC substrate for SERS activity, including enhancement factor, uniformity, and stability.
• Label-free detection of cotinine in standard solutions, synthetic urine, and saliva using SERS.
• Principal component analysis (PCA) for spectral analysis of Rhodamine 6G and cotinine.

Main Results:

• PlQC demonstrated high sensitivity (enhancement factor ~10^14), uniformity, reproducibility, and stability.
• Successful label-free detection of cotinine down to 1 ng/mL in standard solutions.
• Detection of cotinine at nanogram levels in synthetic urine and saliva samples.
• PCA confirmed the suitability of PlQC for label-free detection of single biomolecules.

Conclusions:

• PlQC serves as a highly effective SERS-active substrate for sensitive and label-free biomolecule detection.
• The developed PlQC substrate shows significant potential for clinical diagnostics and environmental monitoring.
• This work advances SERS technology for real-world applications in biomarker analysis.