Functionalization of biopolymers for the neutralization of organophosphates

• Grant number: 24/18342-0
• Support Opportunities: Scholarships in Brazil - Program to Stimulate Scientific Vocations
• Start date: January 20, 2025
• End date: March 01, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Elisa Souza Orth
• Grantee: Izaque Junior Oliveira Silva
• Host Institution: Setor de Ciências Exatas. Universidade Federal do Paraná (UFPR). Ministério da Educação (Brasil)

Abstract

Organophosphates are highly toxic molecules commonly used as pesticides and chemical weapons. Furthermore, they have high chemical stability, which makes the process of controlling and neutralizing them a difficult task and a global concern. Effective responses are needed for cases of poisoning, terrorism, accidents and chemical disasters. Alpha-nucleophiles (e.g., amidoximes) are highly reactive chemical species, capable of accelerating (i.e., catalyzing) the neutralization reactions of organophosphates to less toxic molecules, but they have disadvantages, such as leaching, poisoning of the molecule or non-selectivity. Recent work in our research group has shown that the covalent anchoring of alpha-nucleophiles in biopolymers is capable of: i) modulating selectivity, ii) ensuring that these chemical species do not leach and do not poison each other, and iii) maintaining high reactivity in the neutralization of organophosphates, acting as true biocatalysts. Furthermore, it is possible to use the biopolymeric platform to process these catalysts in solid, colloidal or gel form, expanding the range of possible applications. The study and chemical modification of natural polymers to obtain biocatalysts for organophosphates is an ongoing project, led by PhD student Willian Takarada. To date, synthesis parameters have been optimized to obtain biocatalysts derived from alginate and cellulose containing alpha-nucleophilic groups (such as hydroxamic acids and amidoximes), in addition to the satisfactory testing of these samples in the neutralization of a model organophosphate. This project proposes to functionalize the biopolymer, carboxymethyl cellulose, with amidoxime groups, since this material has not yet been evaluated for this purpose and it is known that neighboring carboxylic acid groups can enhance catalysis. In addition to the synthesis of the biocatalyst, its characterization and kinetic study will be carried out to evaluate its potential in the degradation of toxic organophosphate agents. Finally, a neutralizing gel will be prepared from the biopolymer and its potential to prevent skin poisoning will be evaluated. Thus, it is expected that, at the end of the project, sustainable materials will be obtained that have potential as catalysts and also in the remediation of agrochemical poisoning, through neutralizing gels.