Polymeric Flexible Immunosensor Based on Piezoresistive Micro-Cantilever with PEDOT/PSS Conductive Layer

Area of Science:

• Materials Science
• Biotechnology
• Sensor Technology

Background:

• Development of sensitive and reliable biosensors is crucial for early disease detection and monitoring.
• Polymeric micro-cantilever platforms offer advantages in flexibility and cost-effectiveness for bio-sensing applications.

Purpose of the Study:

• To propose and demonstrate a fully polymeric micro-cantilever for immunoassays.
• To investigate the sensing performance of the micro-cantilever for detecting human immunoglobulin G (IgG).

Main Methods:

• Fabrication of a polymeric micro-cantilever with a parylene-C passivation layer and a poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate) (PEDOT/PSS) strain resistor.
• Optimization of micro-cantilever design and fabrication for improved electrical properties.
• Characterization of mechanical properties (spring constant, deflection sensitivity) and biological sensing performance using an IgG immunoassay.

Main Results:

• Achieved a square resistance of 220 Ω/□ for the PEDOT/PSS conductive layer.
• Measured a spring constant of 0.017 N/m and a deflection sensitivity of 8.59 × 10^-7 nm^-1.
• Demonstrated linear detection of IgG within 10–100 ng/mL with a limit of detection (LOD) of 10 ng/mL.

Conclusions:

• The proposed polymeric micro-cantilever immunosensor is capable of detecting trace amounts of biological substances.
• The flexible, conductive layer-based sensor shows promise for sensitive and specific immunoassays.
• This technology could advance point-of-care diagnostics and biological substance detection.