Charged Polyethylenimine Disinfecting Composition
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Solution Overview
Problem
Current methods for enhancing the antimicrobial effectiveness of linear polyethylenimine (PEI) are insufficient, as they do not adequately improve the charge density necessary for effective antimicrobial action against pathogens, and there are no commercial antimicrobial LPEI products available, with the United States Environmental Protection Agency (EPA) not listing LPEI as an approved active or inert antimicrobial substance.
Innovation Solution
A method is developed to prepare a disinfecting composition comprising charged linear PEI by providing an aqueous solution of PEI hydrochloride, adjusting the pH with a base, adding an organic acid to reduce the pH, removing a significant portion of the salt, and optionally adding water and another organic acid to achieve a pH of 2-7, thereby enhancing the zeta potential and antimicrobial performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods are used to prepare PEI solutions, then the preparation process is simple, but the charge density and antimicrobial performance are insufficient
Solution Approach 1:
The patent applies parameter changes by systematically adjusting pH levels through multiple stages (initial pH adjustment to 9-11, then reduction to 2-7), controlling ionic strength through salt removal (20-100%), and optimizing organic acid concentration. These parameter modifications transform conventional PEI solutions into highly charged formulations with enhanced zeta potential and superior antimicrobial performance against both gram-positive and gram-negative bacteria
Solution Approach 2:
The patent extracts and removes excess salts (20-100% salt removal) from the PEI solution to reduce ionic strength and enhance charge density. This extraction process isolates the active cationic polymer from interfering ions, thereby improving the zeta potential and antimicrobial effectiveness without requiring complex chemical modifications to the PEI structure
2Reliability
If charge density is increased to improve antimicrobial effectiveness, then antimicrobial performance is enhanced, but toxicity may increase
Solution Approach 1:
The patent optimizes the balance between charge density and toxicity by controlling pH within a specific range (2-7) and limiting organic acid concentration. This parameter optimization ensures sufficient protonation of amine groups for antimicrobial activity while maintaining biocompatibility and reducing cytotoxicity, achieving effective disinfection without excessive harm to host cells
Solution Approach 2:
The patent removes 20-100% of salts rather than complete removal, applying partial action to achieve optimal ionic strength. This partial salt removal sufficiently enhances charge density and antimicrobial performance while avoiding the extreme conditions that might lead to precipitation or excessive complexity, thereby maintaining a practical balance between effectiveness and safety
3Reliability
If salt is removed to enhance charge density, then zeta potential increases, but the preparation complexity increases
Solution Approach 1:
The patent extracts excess salts from the PEI solution through dialysis, ultrafiltration, or centrifugal partition chromatography. These extraction methods selectively remove ionic contaminants while retaining the high molecular weight PEI polymer, thereby enhancing zeta potential and charge density through a relatively simple physical separation process
Solution Approach 2:
The patent introduces organic acids as intermediaries to buffer the solution and control pH during the salt removal process. These organic acids mediate between the base addition and final pH adjustment, facilitating gradual salt precipitation or removal while maintaining stable conditions that preserve PEI charge characteristics and simplify the overall process
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 method results in a disinfecting solution with enhanced antimicrobial performance, reduced toxicity, and the ability to leave a persistent, residual antimicrobial film, effectively addressing the limitations of existing PEI formulations.
Implementation Method 1
adding a base in an amount to provide a linear PEI salt solution with a pH between 9-11
Implementation Method 2
adding a first organic acid to the solution obtained in (ii) to reduce the pH to less than 7
Implementation Method 3
removing about 20% to 100% of the salt from the solution obtained in (iii)
Data Source
AI summary
A method of preparing a disinfecting composition comprising charged polyethylenimine (PEI), the method comprising adding a base to an aqueous solution comprising a linear PEI hydrochloride solution to provide a linear PEI salt solution with a pH between 9-11, adding a first organic acid to reduce the pH to less than 7, removing about 20% to 100% of the salt from the solution, and optionally adding water and/or a second organic acid to obtain the disinfecting composition with a pH of 2-7. The method can further comprise adding at least one metal salt to the disinfecting composition. The resulting disinfecting solution can be used to provide antimicrobial products with enhanced antimicrobial performance, reduced toxicity, and/or able to leave a persistent “kill-later” film.