Nitrogen-Doped Graphene Biosensor for Stable Bioreceptor Immobilization
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Solution Overview
Problem
Current methods for immobilizing bioreceptors on graphene surfaces for biosensors face challenges, particularly with covalent functionalization methods that disrupt conductivity and charge carrier mobility, and non-covalent methods lack sensitivity and reliability for large-scale production of sensitive biosensors.
Innovation Solution
A biosensor device featuring a doped graphene layer structure with nitrogen and/or phosphorus atoms (1-10 at%) functionalized with analyte-receptors via covalent linker moieties, optimized for improved sensitivity and reliability, using CVD growth on non-metallic substrates to maintain electronic properties and minimize contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If covalent functionalization methods are used to immobilize bioreceptors on graphene, then immobilization strength is improved, but conductivity and charge carrier mobility deteriorate
Solution Approach 1:
The patent applies local quality by introducing nitrogen dopant atoms at specific locations within the graphene lattice. These localized dopant sites provide covalent bonding positions for bioreceptor immobilization while the undoped regions of graphene maintain their excellent electrical properties, thus resolving the contradiction between strong immobilization and preserved conductivity
Solution Approach 2:
Nitrogen dopant atoms serve as intermediary elements between the graphene substrate and bioreceptors. The nitrogen atoms provide functional groups that enable covalent bonding with bioreceptors, while the graphene backbone maintains its electrical conductivity, thus mediating between the requirements for strong immobilization and preserved electrical properties
2Reliability
If non-covalent functionalization methods are used to immobilize bioreceptors on graphene, then conductivity is preserved, but sensitivity and reliability deteriorate
Solution Approach 1:
The patent creates local functional zones at nitrogen dopant sites where covalent bonding occurs, while the rest of the graphene surface maintains its non-covalent interaction characteristics. This localized approach preserves overall conductivity while providing specific high-sensitivity bonding sites for analyte detection
Solution Approach 2:
The patent changes the chemical parameter of the graphene surface by introducing nitrogen dopants, which alter the local electronic structure and create new bonding sites. This parameter change enables covalent immobilization without requiring extensive covalent functionalization of the entire surface, thus maintaining sensitivity and conductivity
3Measurement precision
If graphene is doped with nitrogen and phosphorus atoms, then sensitivity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating nitrogen dopant atoms during the CVD growth process itself, rather than requiring subsequent doping steps. The dopant precursors are introduced along with the carbon precursor, and nitrogen doping occurs in-situ during graphene formation, simplifying the manufacturing process while achieving the desired sensitivity enhancement
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 solution enhances the sensitivity and reliability of graphene-based biosensors by maintaining electronic properties and ensuring uniform dopant distribution, improving charge injection and reducing Debye screening length, enabling effective detection of analytes with increased sensitivity and commercial viability.
Implementation Method 1
the doped graphene layer structure is doped with nitrogen and/or phosphorus atoms in an amount of from 1 at% to 10 at%
Implementation Method 2
using CVD growth on non-metallic substrates to maintain electronic properties and minimize contamination
Data Source
AI summary
There is provided a biosensor device comprising: a doped graphene layer structure having at least first and second electrical contacts and a sample-surface between said electrical contacts for receiving an analyte composition to be tested; wherein the doped graphene layer structure is doped with nitrogen and/or phosphorus atoms in an amount of from 1 at% to 10 at%; and wherein the sample-surface is functionalised with a plurality of analyte-receptors, each analyte-receptor being bound to a nitrogen or phosphorus atom of the doped graphene layer structure by a covalent linker moiety.