Poly-epsilon caprolactone nanoparticles containing the herbicide atrazine : from the preparation and characterization until herbicide activity evaluation

Orientador: : Leonardo Fernandes FracetoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: A "Revolução Verde" ocorreu na década de 60 e previa o aumento da produção agrícola devido ao crescimento populacional, onde foi intensificado o estudo de novas tecnologias para o aumento da produção de alimentos e rentabilidade dos agricultores. Entre as várias tecnologias, destacou-se a utilização de defensivos agrícolas no controle, prevenção e na eliminação de doenças que interferem na produtividade agrícola. O uso de nanopartículas (NPs) para o carreamento de compostos bioativos para liberação sustentada aumenta o tempo de ação e estabilidade química do ativo no meio, bem como a disponibilidade para ação junto ao organismo alvo. Na agricultura, o uso de NPs visa reduzir a concentração efetiva do ativo a ser utilizado, reduzir de aplicações, reduzir a toxicidade, diminuir a periculosidade e os riscos de contaminação ambiental. O presente trabalho propôs o desenvolvimento de NPs poliméricas de poli-épsilon caprolactona (PCL) como sis-temas carreadores para o herbicida atrazina (ATZ) bem como a avaliação das características físico-químicas destes sistemas, a atividade herbicida e a genotoxicidade das formulações preparadas. As nanocápsulas (NCs/ATZ) e as nanoesferas (NEs/ATZ) contendo ATZ apresentaram diâmetro médio de 483,1 ± 10,4 nm e 408,5 ± 2,5 nm, respectivamente. A ATZ apresentou uma eficiência de encapsulação acima de 90% para as formulações de NE e NC e foram observadas alterações no perfil de liberação da ATZ em comparação com o herbicida ATZ. A estabilidade coloidal e físico-química das formulações foi mantida por um período de 90 dias. O uso de NPs aumentou a retenção da ATZ em ensaios com coluna de solo, sendo que a atividade herbicida se mostrou mais eficaz quando comparada ao ativo ATZ apenas e ao de uma formulação comercial (Gesaprin). A investigação da genotoxicidade das formulações, utilizando o ensaio de aberração cromossômica Allium cepa, mostrou que a encapsulação da ATZ reduziu os efeitos sobre o número de aberrações cromossômicas quando comparadas ao ativo ATZ e à formulação comercial. As formulações de NPs contendo ATZ preparadas neste trabalho apresentam grande potencial para aplicação na agricultura, uma vez que estas podem ter ação herbicida utilizando menor concentração de ativo, reduzem a mobilidade da ATZ no solo e diminuem os efeitos genotóxicos, tornando-se mais seguras ao meio ambiente e reduzindo os riscos de contaminaçãoAbstract: The "Green Revolution" occurred during the decade of 60 and it aimed towards the rapid increase on agriculture production due to population growth, when was intensified the research and development to increase agriculture production and profitability. Among several technologies, herbicides and pesticides have emerged to control, prevent and destroy diseases that interfere in the agricultural productivity. The use of nanoparticles (NPs), as drug delivery system loads to modified drug release profile, increase time of action and increased chemical stability is wells is increase in bioavailability. In agriculture the use of NPs can reduces the amount of chemical used and the number of applications with decrease in toxicity, minimizing the risks of an environmental contamination. This study aims to develop NPs pre-pared with poly-épsilon-caprolactone (PCL) as a carrier system for the herbicide atrazine (ATZ). The formulations were characterized and the herbicide activity and genotoxicity were investigated. The nanocapsules (NCs/ATZ) and nanospheres (NE/ATZ) containing ATZ showed a size average diameter of 483.1±10.4 nm and 408.5±2.5 nm respectively. The ATZ presented encapsulation efficiency over 90% on formulations of NC and NE. The release profiles of the ATZ encapsulated in NPs were changed in relation to the ATZ herbicide only. The colloidal stability over 90 days showed that the formulations were stable. The use of NPs increased the retention of ATZ on soil column and showing that the herbicide was more active when compared to ATZ or a commercial formulation (Gesaprin). The genotoxicity evaluation showed that the encapsulation of ATZ reduced the toxic effects on the number of chromosomal aberration when compared to active ATZ and commercial formulation. NPs formulation containing ATZ prepared in this study presented a great potential for application in agriculture, since these formulations have the same herbicide activity (using lower concentration of active compound), reduce the ATZ soil mobility and also decrease the genotoxicity effects of ATZ, and in this way, reducing the risks of environmental contaminationMestradoBioquimicaMestre em Biologia Funcional e Molecula

Nanotechnology Potential in Seed Priming for Sustainable Agriculture

International audienceOur agriculture is threatened by climate change and the depletion of resources and biodiversity. A new agriculture revolution is needed in order to increase the production of crops and ensure the quality and safety of food, in a sustainable way. Nanotechnology can contribute to the sustainability of agriculture. Seed nano-priming is an efficient process that can change seed metabolism and signaling pathways, affecting not only germination and seedling establishment but also the entire plant lifecycle. Studies have shown various benefits of using seed nano-priming, such as improved plant growth and development, increased productivity, and a better nutritional quality of food. Nano-priming modulates biochemical pathways and the balance between reactive oxygen species and plant growth hormones, resulting in the promotion of stress and diseases resistance outcoming in the reduction of pesticides and fertilizers. The present review provides an overview of advances in the field, showing the challenges and possibilities concerning the use of nanotechnology in seed nano-priming, as a contribution to sustainable agricultural practices

Evaluation of Cyto- and Genotoxicity of Poly(lactide-co-glycolide) Nanoparticles

This work reports on an analysis of the cyto- and genotoxicity of poly(lactide-co-glycolide) polymer nanoparticles, in an attempt to evaluate their mutagenic effects. Fibroblast (3T3) and human lymphocyte cell cultures were exposed to solutions containing three different concentrations of nanoparticles (5.4, 54 and 540 mu g/mL, polymer mass/volume of solution). The nanoparticles were characterized in terms of their hydrodynamic diameters, zeta potentials and polydispersity indices. The morphology of the particles was determined by atomic force microscopy. The PLGA nanospheres presented a size of 95 nm, a zeta potential of -20 mV and a spherical morphology. Cellular viability assays using fibroblast cells showed no significant alterations compared with the negative control. A cytogenetic analysis of human lymphocyte cells showed no significant changes in the mitotic index in relation to the control, indicating that in the concentration range tested, the particles used in the experimental models did not present cyto- or genotoxicity. For the tests conducted in this work we can conclude that biodegradable and biocompatible PLGA nanospheres are not toxic in the cell cultures tested (fibroblast and lymphocyte cells) and in the range of concentrations employed. The results provide new information concerning the toxic effects of particles produced using PLGA.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Evaluation of the Genotoxicity of Chitosan Nanoparticles for Use in Food Packaging Films

The use of nanoparticles in food packaging has been proposed on the basis that it could improve protection of foods by, for example, reducing permeation of gases, minimizing odor loss, and increasing mechanical strength and thermal stability. Consequently, the impacts of such nanoparticles on organisms and on the environment need to be investigated to ensure their safe use. In an earlier study, Moura and others (2008a) described the effect of addition of chitosan (CS) and poly(methacrylic acid) (PMAA) nanoparticles on the mechanical properties, water vapor, and oxygen permeability of hydroxypropyl methylcellulose films used in food packaging. Here, the genotoxicity of different polymeric CS/PMAA nanoparticles (size 60, 82, and 111 nm) was evaluated at different concentration levels, using the Allium cepa chromosome damage test as well as cytogenetic tests employing human lymphocyte cultures. Test substrates were exposed to solutions containing nanoparticles at polymer mass concentrations of 1.8, 18, and 180 mg/L. Results showed no evidence of DNA damage caused by the nanoparticles (no significant numerical or structural changes were observed), however the 82 and 111 nm nanoparticles reduced mitotic index values at the highest concentration tested (180 mg/L), indicating that the nanoparticles were toxic to the cells used at this concentration. In the case of the 60 nm CS/PMAA nanoparticles, no significant changes in the mitotic index were observed at the concentration levels tested, indicating that these particles were not toxic. The techniques used show promising potential for application in tests of nanoparticle safety envisaging the future use of these materials in food packaging.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Nanocarrier-Mediated Delivery of miRNA, RNAi, and CRISPR-Cas for Plant Protection: Current Trends and Future Directions

Funding Information: M.M. thanks the Biotechnology Institute of Ankara University and Bioproducts and Biosystems department, Aalto University for support during the study. L.F.F., J.L.O., and L.B.C. thank the São Paulo Research Foundation (FAPESP, 2017/21004-5, 2018/21142-1, and 2018/23608-8). The authors are grateful for the financial support provided by CAPES (Project 88881.191767/2018-01). A.E.S.P. is grateful for a postdoctoral grant provided by CAPES-COFECUB (88887.363975/2010-00). In addition, L.F.F. thanks the National Council for Scientific and Technological Development (CNPq). All authors are greatful to FinELib for the support to make this article open access. Publisher Copyright: © 2021 The Authors. Published by American Chemical Society.Current trends in plant genetic transformation technologies, i.e., designing and applying molecules like miRNA, RNAi, and CRISPR-Cas, largely enable researchers to target specific sites in the plant genome to avert the growing biotic and abiotic threats to plants. However, the delivery of these molecules through conventional techniques brings an array of drawbacks such as low efficiency due to the cell wall barrier, tissue damage that leads to browning or necrosis, degradation of these biomolecules by physiological conditions (high temperature, harsh pH, and light), and plant-specific protocols. The advancements in nanotechnology offer an excellent alternative for the safe and highly efficient delivery of biomolecules such as miRNA, CRISPR-Cas, and RNAi without damaging the plant tissues. Nanoparticle (polymeric, metallic, magnetic, silica, carbon, etc.)-based delivery of biomolecules can be efficiently utilized especially for plant protection applications. Herein, we present a comprehensive overview of current trends (with a focus on the previous five years) in nanoparticle-based delivery of miRNA, RNAi, CRISPR-Cas and simillar biomolecules for plant protection applications. In addition, a future perspective focuses on the research gaps and unexplored potentials of nanoparticles for the delivery of biomolecules.Peer reviewe

Controlled release system for ametryn using polymer microspheres: Preparation, characterization and release kinetics in water

The purpose of this work was to develop a modified release system for the herbicide ametryn by encapsulating the active substance in biodegradable polymer microparticles produced using the polymers poly(hydroxybutyrate) (PHB) or poly(hydroxybutyrate-valerate) (PHBV), in order to both improve the herbicidal action and reduce environmental toxicity. PHB or PHBV microparticles containing ametryn were prepared and the efficiencies of herbicide association and loading were evaluated, presenting similar values of approximately 40%. The microparticles were characterized by scanning electron microscopy (SEM), which showed that the average sizes of the PHB and PHBV microparticles were 5.92 +/- 0.74 mu m and 5.63 +/- 0.68 mu m, respectively. The ametryn release profile was modified when it was encapsulated in the microparticles, with slower and more sustained release compared to the release profile of pure ametryn. When ametryn was associated with the PHB and PHBV microparticles, the amount of herbicide released in the same period of time was significantly reduced, declining to 75% and 87%, respectively. For both types of microparticle (PHB and PHBV) the release of ametryn was by diffusion processes due to anomalous transport (governed by diffusion and relaxation of the polymer chains), which did not follow Fick's laws of diffusion. The results presented in this paper are promising, in view of the successful encapsulation of ametryn in PHB or PHBV polymer microparticles, and indications that this system may help reduce the impacts caused by the herbicide, making it an environmentally safer alternative. (C) 2010 Elsevier B.V. All rights reserved