Real-time biodetection using a smartphone-based dual-color surface plasmon resonance sensor.

Area of Science:

• Optoelectronics
• Biosensing
• Nanotechnology

Background:

• Surface Plasmon Resonance (SPR) sensors offer label-free detection capabilities.
• Traditional SPR setups often require complex and expensive optical components.
• There is a need for portable, cost-effective biosensing platforms.

Purpose of the Study:

• To develop a compact and affordable fiber optic SPR sensor utilizing smartphone technology.
• To leverage the color selectivity of smartphone cameras for enhanced detection.
• To demonstrate the sensor's efficacy in real-time biodetection, specifically for immunoglobulin G (IgG) concentration measurement.

Main Methods:

• A red-green dual-color fiber optic SPR sensor was designed with a simplified optical configuration, omitting prisms and gratings.
• Smartphone cameras were employed for simultaneous real-time monitoring of red and green color channels.
• The sensor's performance was evaluated using refractive index measurements and IgG concentration detection.

Main Results:

• The sensor exhibited a linear response over a refractive index range of 1.326 to 1.351 (R² = 0.991) with a resolution of 2.3 × 10⁻⁴ RIU.
• A linear SPR response was observed for IgG concentrations from 0.02 to 0.30 mg/mL with good repeatability.
• The dual-color detection method reduced false detection and improved sensitivity.

Conclusions:

• The proposed smartphone-based fiber optic SPR sensor is compact, cost-effective, and simple to operate.
• It enables real-time, label-free biodetection with high sensitivity and reliability.
• Potential applications include public health and environmental monitoring.