Enzymatic Assembly of DNA-Functionalized SWNTs

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Solution Overview

Problem

The low aqueous solubility and difficulty in aligning single-walled carbon nanotubes (SWNTs) have limited their use in various applications, and existing methods for assembling CNTs into nanostructures lack efficient and scalable biological approaches.

Innovation Solution

A method involving phosphodiester bonding catalyzed by ATP-dependent single-strand DNA-ligase is used to functionalize SWNTs, enabling their assembly into macroscopic aggregates through enzymatic ligation reactions, which allows for the formation of macro-scale items by exploiting biological recognition specificity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If covalent chemical modifications are used to overcome low solubility, then aqueous solubility is improved, but physical and electrochemical properties are adversely affected

Engineering Contradiction:

Improveaqueous solubilityVSAvoidphysical and electrochemical properties

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent uses DNA as an intermediary molecule that binds non-covalently to SWNTs, providing aqueous solubility without modifying the nanotube structure. The DNA acts as a mediator between the hydrophobic SWNT surface and the hydrophilic aqueous environment, enabling solubility while preserving the intrinsic physical and electrochemical properties of the carbon nanotubes.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the surface properties of SWNTs by coating them with DNA molecules, which alters the surface chemistry from hydrophobic to hydrophilic. This parameter change enables aqueous solubility while maintaining the core structure and properties of the carbon nanotubes intact, avoiding the adverse effects of covalent modification.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If biological molecules are used to separate and purify CNTs, then solubility is improved with less invasive modification, but assembly into higher-order nanostructures remains difficult

Engineering Contradiction:

Improveaqueous solubilityVSAvoidassembly into nanostructures

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent demonstrates that DNA-functionalized SWNTs can perform multiple functions: they maintain aqueous solubility, enable separation and purification by ion exchange chromatography, and facilitate assembly into higher-order nanostructures through biological recognition motifs. This multi-functionality resolves the contradiction by showing that biological molecules can simultaneously provide solubility and enable structured assembly.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent exploits the intrinsic ability of DNA to bind and disperse SWNT bundles, and further utilizes biological recognition motifs (such as RecA-based sequences) to automatically guide the assembly of SWNTs into desired nanostructures. The system is self-directing, using the DNA's own recognition properties to organize the nanotubes without external intervention.

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If DNA is used to assemble CNTs into nanostructures, then recognition specificity is improved, but scaling to macroscopic aggregates requires new enzymatic approaches

Engineering Contradiction:

Improverecognition specificityVSAvoidscaling to macroscopic aggregates

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces spontaneous or non-specific assembly mechanisms with an enzymatic system. ssDNA-ligase catalyzes the formation of phosphodiester bonds between DNA-functionalized SWNTs, providing a controlled and scalable mechanism for assembling macroscopic aggregates. This enzymatic approach maintains the recognition specificity of DNA while enabling efficient scaling to macroscopic dimensions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the assembly mechanism from passive or non-enzymatic to active enzymatic catalysis. By introducing ssDNA-ligase, the system gains the ability to form stable phosphodiester linkages between DNA-functionalized SWNTs, enabling controlled assembly into macroscopic aggregates while maintaining the specificity provided by DNA recognition sequences.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10526628B2Enzyme-mediated assimilation of DNA-functionalized single-walled carbon nanotubes (SWNTs)

Publication Date: 2020.01.07 UNITED STATES OF AMERICA THE AS REPRESENTED BY THE SEC OF THE ARMY

AI summary

Select embodiments of the present invention employ biological means to direct assemble CNT-based nanostructures, allowing for scaling to macrostructures for manufacture. In select embodiments of the present invention, a method is provided for assembling DNA-functionalized SWNTs by phosphodiester bonding catalyzed by ssDNA-ligase to form macroscopic CNT aggregates.