Statistical quantification of SERS signals in microfluidic flow using AuNP-bound polystyrene microparticles.

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Nanotechnology

Background:

• Surface-enhanced Raman scattering (SERS) offers high sensitivity but faces challenges in quantitative analysis due to substrate instability and signal variability.
• Developing stable and sensitive SERS substrates is crucial for reliable quantitative detection of analytes.

Purpose of the Study:

• To develop and evaluate novel SERS substrates for the quantitative detection of 4-aminobenzenethiol (4-ATP).
• To investigate the performance of gold nanoparticle (AuNP)-bound polystyrene (PS) microparticles as SERS substrates, particularly under flow conditions in a microfluidic chip.

Main Methods:

• Synthesized and characterized citrate-stabilized AuNPs, biotin-functionalized AuNPs, and AuNP-bound PS microparticles.
• Performed SERS measurements of 4-ATP in aqueous solutions using static and microfluidic chip-based setups.
• Analyzed SERS signal intensity distributions and dependence on flow rate for quantitative assessment.

Main Results:

• AuNP-bound PS microparticles demonstrated approximately twice the detection sensitivity for 4-ATP compared to conventional AuNPs.
• Integrating AuNP-bound PS microparticles into a microfluidic chip significantly enhanced 4-ATP detection sensitivity under controlled flow.
• Optimal detection sensitivity was achieved at a flow rate of 0.66 μL·min⁻¹, yielding a detection limit of 1.9 μM.

Conclusions:

• AuNP-bound PS microparticles represent highly efficient SERS substrates for quantitative analysis.
• The microfluidic chip integration enables sensitive and stable SERS detection of 4-ATP under optimized flow conditions.
• This approach offers a promising platform for advanced quantitative SERS applications.