Up-conversion Phosphor Coatings for Antimicrobial Action
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Solution Overview
Problem
Current antimicrobial coatings for surfaces have limitations, including short-lived effectiveness, potential toxicity, and the development of resistance, particularly with chemical substances, and concerns about the long-term impact of heavy metals on humans and the environment.
Innovation Solution
A curable composition comprising a film-forming polymer, up-conversion phosphors selected from specific lanthanoid-doped silicates, and optional additives, which emit antimicrobial radiation upon irradiation with lower energy wavelengths, providing long-lasting protection against microorganisms without impairing surface properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical substances or metal particles are used for antimicrobial coatings, then antimicrobial effectiveness is improved, but toxicity and environmental harm worsen
Solution Approach 1:
The patent replaces chemical and metallic antimicrobial mechanisms with a physical mechanism: up-conversion phosphors that convert visible or infrared light into UV radiation. This physical light-based approach eliminates the need for toxic chemical substances and heavy metal particles, resolving the contradiction between effectiveness and toxicity.
Solution Approach 2:
The invention changes the fundamental parameter of antimicrobial action from chemical interaction to physical radiation. By using phosphors that emit UV radiation upon light absorption, the system achieves antimicrobial effectiveness through a different physical-chemical parameter (electromagnetic radiation wavelength conversion) rather than through toxic substance interaction.
2Reliability
If conventional antimicrobial materials are used, then initial antimicrobial action is improved, but duration of action worsens due to short-lived effectiveness
Solution Approach 1:
The up-conversion phosphor coating is self-powered, converting ambient visible or infrared light into antimicrobial UV radiation continuously. This eliminates the need for external power sources or periodic reapplication, enabling long-lasting antimicrobial action without depleting active ingredients, thus resolving the short-lived effectiveness problem.
3Reliability
If chemical disinfectants are used, then antimicrobial effectiveness is improved, but development of resistance worsens
Solution Approach 1:
By replacing chemical disinfectants with physical UV radiation generated through up-conversion phosphors, the patent eliminates the selective pressure that drives microbial resistance development. Microorganisms cannot develop resistance to physical UV radiation in the same way they develop resistance to chemical antibiotics, resolving this contradiction.
4Reliability
If metal particles are incorporated into coatings, then antimicrobial property is improved, but long-term stability worsens due to heavy metal degradation
Solution Approach 1:
The patent substitutes heavy metal particles with organic up-conversion phosphor materials that do not suffer from heavy metal degradation, leaching, or accumulation problems. These phosphors are photostable and maintain their antimicrobial functionality over long periods without the stability issues associated with metal particles.
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 composition achieves sustained antimicrobial action against a wide range of pathogens, including bacteria, viruses, and fungi, with enhanced chemical and mechanical stability, and does not compromise the appearance or functionality of the coated surfaces.
Implementation Method 1
the exploitation of the effect of what is called up-conversion is also known. This uses phosphor particles with which electromagnetic radiation having wavelengths above UV light, especially visible light or infrared light, can be converted to electromagnetic radiation having shorter wavelength
Implementation Method 2
DNA has good absorption of electromagnetic radiation in the wavelength range between 200 nm and 300 nm, and particularly good absorption between 250 nm and 280 nm, and so this radiation is particularly suitable against DNA. It is thus possible to inactivate pathogenic microorganisms (viruses, bacteria, yeasts, moulds inter alia) with such irradiation. According to the duration and intensity of the irradiation, the structure of DNA can be destroyed.
Data Source
AI summary
A curable composition for production of coatings with an antimicrobial property contains at least one film-forming polymer, at least one up-conversion phosphor, optionally, at least one additive, and optionally, at least one curing agent. The phosphor is selected from the idealized general formula (I), A1-x-y-zB*yB2SiO4:Ln1x,Ln2z,, where x=0.0001-0.05, z=0 or z=0.0001 to 0.3, and y=x+z; A is selected from Mg, Ca, Sr, and Ba; B is selected from Li, Na, K, Rb, and Cs; B* is selected from Li, Na, and K; where B is the same as B* or B is not the same as B*, and B and B* are preferably not the same; Ln1 is selected from praseodymium (Pr), erbium (Er), and neodymium (Nd); and Ln2 is optionally selected from gadolinium (Gd).