Extreme red shifted SERS nanotags.

Area of Science:

• Nanotechnology
• Spectroscopy
• Materials Science

Background:

• Surface-enhanced Raman scattering (SERS) is a powerful analytical technique.
• Developing robust SERS nanotags for specific applications, especially at longer excitation wavelengths, remains a challenge.
• Chalcogenopyrylium dyes offer unique optical properties but require effective surface functionalization for SERS applications.

Purpose of the Study:

• To construct and characterize novel SERS nanotags operating at 1280 nm excitation.
• To investigate the use of chalcogenopyrylium dyes as reporter molecules for SERS.
• To evaluate the performance of these nanotags in terms of sensitivity and signal stability.

Main Methods:

• Synthesis of a library of 14 chalcogenopyrylium dyes with varying substituents.
• Functionalization of hollow gold nanoshells (HGNs) with selected reporter dyes.
• Characterization of SERS nanotags using spectroscopy and microscopy.
• Determination of limits of detection (LOD) and signal analysis.

Main Results:

• Successfully constructed SERS nanotags using chalcogenopyrylium dyes and HGNs for 1280 nm excitation.
• Demonstrated strong adsorption of dyes onto HGNs due to multiple chalcogen atoms, enhancing SERS signals.
• Achieved picomolar limits of detection (LOD) for the developed nanotags.
• Utilized principal component analysis to identify and classify individual reporter molecules based on their SERS spectra.

Conclusions:

• The developed 1280 nm SERS nanotags exhibit exceptional performance due to strong dye-HGN adsorption.
• Chalcogenopyrylium dyes are effective reporters for long-wavelength SERS applications.
• The findings open avenues for highly sensitive SERS-based detection methods.