FET Biosensor Pixelated Gate for Single-Molecule Detection
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Solution Overview
Problem
Current biosensors face challenges in detecting biomarkers at extremely low concentrations and have a limited dynamic range, making them ineffective for early disease detection and clinical screening, as they become 'blind' to further ligand recognition events after a single or few interactions, and are impractical for tracking ligands in biologically relevant media due to size constraints and low reproducibility.
Innovation Solution
A field-effect transistor (FET) biosensor with a gate electrode functionalized into uncoupled domains covered by a hydrophobic ionic conducting material, allowing for electrical/ionic contact with a water electrolyte or bio-fluid while protecting the semiconductor, enabling high sensitivity and wide concentration dynamic range by preventing rapid deactivation of biological recognition elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensing surface is miniaturized to the highest possible limit, then single-molecule detection sensitivity is improved, but the dynamic range is reduced and detection time becomes impractically long for dispersed biomarkers
Solution Approach 1:
The gate electrode is divided into multiple uncoupled domains that act as independent sensing units. Each domain contains a limited number of biological recognition elements, preventing conformational changes from spreading across the entire surface. This segmentation allows the sensor to maintain single-molecule detection sensitivity while providing multiple independent detection sites, thereby reducing the wait time for detecting dispersed biomarkers in biological fluids.
Solution Approach 2:
The patent modifies the electrical parameters of the FET by creating uncoupled domains with different capacitance values. Each domain's electrical response is independent, allowing the system to detect a broader range of ligand concentrations. This parameter change enables the sensor to maintain high sensitivity for single-molecule detection while also being able to detect biomarkers at various concentrations in dispersed biological samples.
2Measurement precision
If a large number of biological recognition elements are used to detect few ligands, then detection sensitivity is improved, but the sensor rapidly deactivates after initial ligand recognition events
Solution Approach 1:
The gate electrode surface is segmented into multiple uncoupled domains, each containing a controlled number of biological recognition elements. When a ligand binding event occurs in one domain, the conformational change is confined to that domain only and cannot propagate to other domains. This prevents the rapid deactivation that would occur in a continuous surface, allowing the sensor to maintain sensitivity and operational duration by preserving the activity of recognition elements in uncoupled domains even after some have bound ligands.
3Measurement precision
If the gate electrode is fully functionalized with biological recognition elements, then detection sensitivity is maximized, but conformational changes spread across the entire surface causing rapid deactivation
Solution Approach 1:
The gate electrode is divided into multiple uncoupled domains that are electrically isolated from each other. Each domain can be independently functionalized with biological recognition elements, maintaining high detection sensitivity through the collective effect of multiple domains. The electrical isolation prevents conformational changes from spreading between domains, ensuring that detection events in one domain do not affect the conformational state and reliability of recognition elements in other domains, thus improving the reproducibility of detection events across multiple measurements.
4Measurement precision
If nano-systems are used to achieve nanoscale spatial localization, then single-molecule detection is enabled, but the systems are limited by low reproducibility and production scalability
Solution Approach 1:
The patent replaces complex mechanical nano-positioning systems with an electrical field-based sensing approach using FETs. Instead of requiring precise mechanical placement of individual recognition elements at the nanoscale, the invention uses the electrical field sensitivity of FETs to detect binding events. This substitution maintains single-molecule detection capability while dramatically improving ease of manufacture and production scalability, as FETs can be fabricated using standard semiconductor manufacturing techniques rather than requiring complex nano-positioning machinery.
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
The biosensor achieves sensitive detection of biomarkers at extremely low concentrations and spans a wide concentration dynamic range, preventing rapid deactivation and maintaining sensitivity across multiple ligand recognition events, thus enabling early detection of biomarkers in clinical screening.
Implementation Method 1
a hydrophobic ionic conducting material to maintain semiconductor stability in water environments
Implementation Method 2
field-effect transistor (FET) biosensor... whose conductance is affected by the presence of a complementary DNA target
Data Source
AI summary
Described herein is a field effect transistor sensor including: a substrate, a source electrode, a drain electrode, a gate electrode functionalized with a layer of biological recognition elements, a source-drain channel and a semiconductor layer. The layer of biological recognition elements of the gate electrode is patterned into a plurality of uncoupled domains.