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Preparation of Silicon Nanowire Field-effect Transistor for Chemical and Biosensing Applications
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Ultrasensitive Detection of PSA Using Antibodies in Crowding Polyelectrolyte Multilayers on a Silicon Nanowire
Galina V Presnova1, Denis E Presnov2,3, Mariya M Ulyashova1
1Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia.
Polymers
|February 10, 2024
Summary
This study introduces a novel nanowire field-effect transistor (NWFET) immunosensor for rapid prostate-specific antigen (PSA) detection. The innovative polyelectrolyte matrix enhances antibody fixation and antigen interaction, enabling ultra-low detection limits for early prostate cancer screening.
Area of Science:
- Nanotechnology
- Biomedical Engineering
- Analytical Chemistry
Background:
- Field-effect transistors with nanowire channels (NWFETs) offer label-free, real-time biomarker detection.
- Prostate cancer diagnosis relies on accurate and sensitive detection of biomarkers like prostate-specific antigen (PSA).
- Existing detection methods may lack the speed, sensitivity, or real-time capabilities required for early screening.
Purpose of the Study:
- To develop and characterize a novel NWFET-based immunosensor for the sensitive and real-time detection of prostate-specific antigen (PSA).
- To investigate the use of polyelectrolyte multilayers (polyethylenimine (PEI) and polystyrene sulfonate (PSS)) for enhanced antibody immobilization and antigen interaction within the NWFET architecture.
- To evaluate the performance of the developed immunosensor, including its sensitivity, limit of detection (LOD), and response time for PSA detection.
Main Methods:
- Fabrication of NWFETs using silicon-on-insulator (SOI) material, e-beam lithography, thin film deposition, and reactive-ion etching.
- Coating of silicon nanowires (NWs) with alternating layers of PEI and PSS to create a 3-D matrix for antibody immobilization.
- Investigation of PSA-antibody interactions within the polyelectrolyte matrix using SEM and AFM with gold nanoparticle-labeled antibodies.
- Characterization of the immunosensor's response to PSA, pH sensitivity, LOD, and real-time detection capabilities.
Main Results:
- The polyelectrolyte matrix facilitated "soft fixation" and optimal orientation of antibodies, enhancing PSA interaction.
- PSA was observed to penetrate the matrix and concentrate near the nanowire surface, crucial for detection.
- The developed NWFET immunosensor demonstrated high sensitivity to pH (71 mV/pH) and an ultra-low LOD of 0.04 fg/mL for PSA.
- The immunosensor provided a response in less than a minute, enabling real-time PSA measurement.
Conclusions:
- The PEI/PSS coated NWFET immunosensor offers a highly sensitive and rapid method for PSA detection.
- This technology shows significant promise for early prostate cancer screening and point-of-care (POC) diagnostic systems.
- The macromolecular crowding effect within the polyelectrolyte matrix is key to the immunosensor's enhanced performance.
