FET Biosensor for CVD Biomarker Detection

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Solution Overview

Problem

Conventional methods for detecting cardiovascular disease biomarkers in liquid samples, such as ELISA and electrochemical redox methods, are time-consuming and have low sensitivity, especially when dealing with samples of high ionic strength like human serum due to the charge-screening effect.

Innovation Solution

A biosensor system utilizing a transistor with a reactive electrode and a receptor immobilized on its surface, applying a voltage pulse to monitor response currents correlated to the biomarker concentration, allowing for direct analysis of liquid samples without the need for dilution and overcoming the charge-screening effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional methods such as ELISA and electrochemical redox method are used for detecting CVD biomarkers, then the detection can be performed, but the detection is time-consuming and has low sensitivity

Engineering Contradiction:

Improvedetection sensitivityVSAvoiddetection time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces conventional mechanical/chemical detection methods (ELISA, electrochemical redox) with a field-effect transistor-based biosensor that utilizes electrical field effects to detect biomarker binding events directly, eliminating time-consuming washing and signal amplification steps while achieving high sensitivity through direct transduction of binding events into electrical signals

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from conventional optical or electrochemical readouts to electrical current measurements using FET biosensors, enabling real-time, label-free detection of biomarker-concentration with high sensitivity and reduced detection time

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional detection methods are used on high ionic strength samples like human serum, then the biomarker detection can be attempted, but the charge-screening effect causes severe difficulty in detection

Engineering Contradiction:

Improvedetection reliability in high-salt samplesVSAvoiddetection difficulty due to charge-screening effect

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces electrochemical redox methods that are sensitive to ionic strength with field-effect transistor-based detection that measures changes in electrical field at the sensor surface, making the detection insensitive to bulk solution ionic strength and eliminating charge-screening interference

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a receptor layer immobilized on the FET gate that specifically binds the target biomarker, acting as an intermediary that transduces biomarker binding events into measurable electrical signals while being insensitive to the ionic environment of the sample

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This method provides a faster and more sensitive detection of cardiovascular disease biomarkers, capable of analyzing high-salt concentration samples like human serum without dilution, enhancing the detection limit and reliability of biomarker concentration analysis.

Implementation Method 1

a reactive electrode spaced apart from the gate terminal of the transistor, the reactive electrode having a receptor immobilized thereon for specific binding with the CVD biomarker in the liquid sample

Methodology Applied

Scientific EffectSpecific binding: Adsorption

Implementation Method 2

applying a voltage pulse between the reactive electrode and the source of the transistor, the voltage pulse having a pulse width; monitoring a response current, which is produced in response to the voltage pulse, within the pulse width from the biosensor

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10107824B2Method for detecting cardiovascular disease biomarker

Publication Date: 2018.10.23 NATIONAL TSING HUA UNIVERSITY

AI summary

A method for analyzing concentration of a cardiovascular disease (CVD) biomarker in a liquid sample includes: applying the liquid sample to a biosensor, the biosensor including a transistor having a drain, a source, and a gate terminal disposed between the gate and the source, and a reactive electrode spaced apart from the gate terminal of the transistor and having a receptor immobilized thereon for specific binding with the CVD biomarker, the liquid sample being in contact with the gate terminal and the reactive electrode; applying a voltage pulse between the reactive electrode and the source, the voltage pulse having a pulse width; monitoring a response current in response to the voltage pulse; and analyzing the response current.