Fluorescent Silk Photoreaction for Visible-Light Surface Disinfection

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Solution Overview

Problem

Conventional photocatalysis for antimicrobial and antiviral applications is limited by cytotoxicity and the need for noncytotoxic, biocompatible carriers that can generate reactive oxygen species (ROS) in a controlled and biodegradable manner, especially under visible light activation.

Innovation Solution

Genetically hybridized fluorescent silk, specifically mKate2 silk, is used to generate ROS upon visible light exposure, providing a biocompatible and biodegradable platform for antimicrobial and antiviral applications by combining the properties of far-red fluorescent proteins with silk fibers, which can be woven into fabrics or used in various forms for disinfection and preservation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional red fluorescent proteins are used to generate reactive oxygen species, then photocatalytic efficiency is improved, but cytotoxicity increases

Engineering Contradiction:

Improvephotocatalytic efficiencyVSAvoidcytotoxicity

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent changes the excitation wavelength parameter from conventional blue/green light to red light (610-650 nm), which reduces cytotoxicity while maintaining photocatalytic efficiency. The far-red fluorescent protein mKate2 is specifically engineered to be excited by red light, generating reactive oxygen species with lower cellular damage compared to conventional RFPs excited by shorter wavelengths.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material by genetically fusing the far-red fluorescent protein mKate2 with silk fibroin. This composite combines the ROS-generating capability of fluorescent proteins with the biocompatibility, biodegradability, and structural properties of silk, resulting in a material that is both effective for photocatalysis and safe for biological applications.

Inventive Principle:

Principle #40Composite materials

2Power

If semiconductor nanoparticles are used for plasmonic photocatalysis, then photocatalytic efficiency under visible light is improved, but biocompatibility and scalability are worsened

Engineering Contradiction:

Improvephotocatalytic efficiencyVSAvoidbiocompatibility and scalability

Core Design Contradiction:

PowerVSAdaptability or versatility

Solution Approach 1:

The patent replaces expensive, hard-to-scale semiconductor nanoparticles with a biologically produced material (transgenic silk) that can be manufactured at low cost through silkworm cultivation. The silk material is inherently biodegradable and biocompatible, eliminating the need for complex purification and safety protocols required for nanoparticle systems.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent utilizes the self-organizing and self-assembling properties of silk fibroin to naturally incorporate and position the far-red fluorescent protein throughout the silk matrix. This self-assembly process eliminates the need for complex nanoparticle synthesis and functionalization steps, enabling simple large-scale production through biological means.

Inventive Principle:

Principle #25Self-service

3Reliability

If conventional fluorescent proteins are used for ROS generation, then antimicrobial activity is improved, but biodegradability and eco-friendliness are worsened

Engineering Contradiction:

Improveantimicrobial activityVSAvoidbiodegradability

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

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 mKate2 silk effectively reduces microbial colonies under visible light without the use of harmful nanoparticles, offering scalable, eco-friendly, and biodegradable solutions for antimicrobial and antiviral applications, including skin disinfection, filtration, and food preservation.

Implementation Method 1

The phototoxicity of fluorescent proteins, in particular red fluorescent proteins (RFP) is unanimously acknowledged in several different scientific communities; RFP often generates and releases reactive oxygen species (ROS) upon light excitation

Methodology Applied

Scientific EffectPhotosensitization:

Implementation Method 2

RFP has also been used as a means of selectively damaging specific proteins upon light activation, which is also known as chromophore-assisted light inactivation

Methodology Applied

Scientific EffectPhototoxicity:

Implementation Method 3

applying light in the visible spectrum for a predetermined amount of time to the placed quantity of genetically hybridized fluorescent silk

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS11925117B2Light activated photoreaction via genetic hybridization of far-red fluorescent protein and silk

Publication Date: 2024.03.05 PURDUE RES FOUND

AI summary

A method of disinfection of a surface of a subject of harmful microorganisms including pathogenic bacteria and viruses upon visible light irradiation using a hybridized fluorescent silk is provided. The method includes placing a predetermined quantity of the hybridized fluorescent silk i) directly on to a skin surface of a subject; or ii) on a medium and then placing the medium on the skin surface of the subject. The method further includes applying light in the visible spectrum for a predetermined amount of time to the placed quantity of hybridized fluorescent silk, wherein the hybridized fluorescent silk is one of KillerRed, SuperNova, KillerOrange, Dronpa, TurboGFP, mCherry, or any combination thereof.