A novel C-shaped, gold nanoparticle coated, embedded polymer waveguide for localized surface plasmon resonance based...

Area of Science:

• Nanotechnology
• Optical Engineering
• Biomedical Sensing

Background:

• Localized Surface Plasmon Resonance (LSPR) is a phenomenon utilized in optical sensing.
• Optical waveguides offer a platform for integrated photonic devices.
• Affinity biosensors require high sensitivity for detecting subtle environmental changes.

Purpose of the Study:

• To develop a novel embedded optical waveguide sensor for refractive index detection.
• To investigate the use of gold nanoparticles (GNPs) coated on a C-shaped polymer waveguide for enhanced sensing.
• To evaluate the sensitivity and resolution of the developed biosensor.

Main Methods:

• Fabrication of a C-shaped SU8 polymer waveguide on a silicon wafer using single-step patterning.
• Coating the waveguide with gold nanoparticles (GNPs) to leverage LSPR.
• Characterization of the sensor's absorbance response to refractive index variations.
• Measurement of sensitivity and resolution at 530 nm.

Main Results:

• The sensor demonstrated a linear absorbance response to refractive index changes between 1.33 and 1.37.
• A GNP-coated C-bent waveguide exhibited a sensitivity of approximately 5 ΔA/RIU.
• The sensor probe achieved a resolution of approximately 2 × 10⁻⁴ RIU.

Conclusions:

• The novel C-shaped optical waveguide sensor functionalized with gold nanoparticles shows significant potential for affinity biosensing applications.
• The sensor design enables detection of minor refractive index variations with high sensitivity and resolution.
• This technology is suitable for developing analysis chips for microenvironment monitoring.