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Disposable noncompetitive immunosensor for free and total prostate-specific antigen based on capacitance measurement
César Fernández-Sánchez1, Calum J McNeil, Keith Rawson
1Institute for Nanoscale Science and Technology, School of Clinical and Laboratory Sciences, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, U.K.
Analytical Chemistry
|October 1, 2004
Summary
A novel one-step immunosensor detects prostate-specific antigen (PSA) using lateral flow and impedance. This rapid, portable device shows potential for early prostate cancer screening by detecting free and total PSA down to 3 ng/mL.
Area of Science:
- Biosensors and electrochemical detection
- Immunoassay development
- Biomarker detection
Background:
- Prostate-specific antigen (PSA) is a key biomarker for prostate cancer.
- Current detection methods can be time-consuming or require complex equipment.
- Development of rapid, sensitive, and user-friendly diagnostic tools is crucial for early cancer detection.
Purpose of the Study:
- To develop a rapid, single-use immunosensor for sensitive detection of free and total PSA.
- To integrate a one-step lateral flow immunoassay with impedance detection.
- To utilize a pH-sensitive polymer layer on an electrochemical transducer for signal generation.
Main Methods:
- Coating nitrocellulose membranes with antibodies against f-PSA and t-PSA.
- Performing noncompetitive immunoassays with PSA, immobilized antibodies, and urease enzyme conjugate.
- Utilizing a urea solution for automatic washing and urease-catalyzed hydrolysis.
- Measuring changes in system capacitance due to pH-induced polymer layer breakdown on an electrochemical transducer.
Main Results:
- Successful integration of lateral flow immunoassay and impedance detection.
- Demonstrated sensitive detection of both free and total PSA.
- Achieved detection limits as low as 3 ng/mL for PSA.
- The system showed measurable capacitance changes within 30 minutes.
Conclusions:
- A one-step immunosensor prototype for PSA detection has been successfully developed.
- The device is portable, easy to use, robust, and simple.
- This technology holds significant potential for prostate cancer screening and early detection.