Biosensor Using Interdigital Electrodes for Antigen Detection
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Solution Overview
Problem
Current biosensors for antigen/antibody reactions lack high sensitivity and efficiency in detecting multiple analytes simultaneously, particularly in rapid and cost-effective methods suitable for high-throughput screening and portable use.
Innovation Solution
A biosensor system utilizing a silicon chip with gold interdigital structures coated with protein A, G, or G′ for immobilizing antibodies, combined with enzyme-marked detection antibodies and redox-active substrates like p-aminophenol for electrochemical readout, allowing for selective and sensitive detection of antigens through amperometric or cyclic voltammetry methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical measurement methods (ellipsometry, surface plasmon resonance) are used to detect antigen/antibody reactions, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex optical measurement systems with a simple electrochemical amperometric detection system. Instead of using ellipsometry or surface plasmon resonance instruments, the invention uses an enzyme-linked immunosorbent assay (ELISA) approach where enzyme-coupled detection antibodies catalyze substrate conversion, and the resulting electrochemical signal is measured with a simple amperometric sensor, thereby eliminating the need for complex optical apparatus while maintaining detection capability
Solution Approach 2:
The patent employs disposable microtiter plates with pre-coated capture antibodies and enzyme-coupled detection antibodies, replacing expensive and complex optical measurement systems with inexpensive, single-use assay systems that achieve comparable or superior detection sensitivity without requiring sophisticated instrumentation
2Productivity
If multiple analytes are detected simultaneously using sensor arrays, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent divides the detection task into separate, independent wells in a microtiter plate, where each well is dedicated to detecting a specific analyte using capture antibodies specific to that analyte. This segmentation allows simultaneous detection of multiple analytes in parallel without requiring complex multi-sensor arrays, as each well functions as an independent detection unit
Solution Approach 2:
The patent creates a universal detection platform using identical enzyme-coupled detection antibodies and substrate systems that can detect multiple different analytes. The same amperometric detection method and enzyme-substrate system are used across all wells, allowing the system to detect various analytes simultaneously without requiring different detection mechanisms for each, thereby simplifying the overall device complexity
3Loss of time
If rapid detection (<10 min) is achieved, then time consumption is reduced, but measurement precision may deteriorate
Solution Approach 1:
The patent performs preliminary preparation by pre-coating microtiter plate wells with capture antibodies specific to target analytes before sample addition. This preliminary immobilization of capture antibodies eliminates the need for time-consuming antibody incubation steps during actual detection, allowing rapid sample addition and immediate antigen-antibody binding while maintaining detection sensitivity
Solution Approach 2:
The patent uses highly active enzyme markers (such as horseradish peroxidase or alkaline phosphatase) coupled to detection antibodies that catalyze substrate conversion extremely rapidly, allowing the detection reaction to complete within minutes. The high catalytic activity of these enzymes enables the system to rush through the detection step quickly while still generating sufficient signal for sensitive measurement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid (<10 min), sensitive, and cost-effective detection of multiple antigens with minimal sample preparation, suitable for medical diagnostics, foodstuff monitoring, environmental monitoring, and bio-threat detection, reducing the need for complex optical apparatus.
Implementation Method 1
coated with protein A, G, or G′ for immobilizing antibodies
Implementation Method 2
enzyme-marked detection antibodies and redox-active substrates like p-aminophenol
Implementation Method 3
the enzymes catalyze a splitting reaction to an optically active molecule
Implementation Method 4
A redox recycling through enzymatic splitting of for example pAP (para aminophenol) at IDS can be induced
Implementation Method 5
For electrochemical readout of the redox recycling a counter-electrode and a reference electrode are necessary
Data Source
AI summary
A biosensor for detecting an antigen using an antigen/antibody coupling includes: a silicon substrate, at least one interdigital electrode pair structure that is located on the silicon substrate, the electrode pair being interspaced at a maximum distance of 1.0 μm; a counter-electrode on the silicon substrate; a reference electrode; a first layer of protein, covering at least the interdigital electrode structure; a selective second protein layer applied to the first layer and containing a capture antibody selected specifically with respect to the antigen of interest and to which the antigen can be coupled. A sensor signal can be read on the interdigital electrode structure, if the antigen is coupled to the capture antibody by way of a sample to be analyzed that comes into contact with the biosensor and a redox reactive molecule is enzymatically released on the sensor surface by an enzyme-marked detection antibody likewise coupled to the antigen.