Investigating at a molecular level the composition of soil rhizosphere that drives eco-corona formation on CuO nanoparticles

• Grant number: 24/18015-9
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry
• Principal Investigator: Diego Stéfani Teodoro Martinez
• Grantee: Laís Gomes Fregolente
• Supervisor: Patrick G Hatcher
• Host Institution: Centro Nacional de Pesquisa em Energia e Materiais (CNPEM). Ministério da Ciência, Tecnologia e Inovação (Brasil). Campinas , SP, Brazil
• Institution abroad: Old Dominion University (ODU), United States
• Associated to the scholarship: 23/13881-7 - Molecular characterization of Eco-corona on 65CuO nanoparticles in tropical environment: Understanding the impacts of soil organic matter from oxisol, biochar conditioning, and Amazonian Dark Earth in the rhizobium-root symbiosis at nano-bio interfaces, BP.PD

Abstract

The nanoparticle corona refers to the layer of macromolecules that spontaneously form onto nanoparticles surface, altering their natural behavior and influencing their stability, reactivity, and ecotoxicity. The composition, structure, and dimensions of this coating depend on both the characteristics of the nanoparticles and the medium in which they are exposed. While the protein corona is a well-established concept related to the adsorption of proteins on nanomaterial surfaces, other exposure mediums have recently been explored, leading to the term "eco-corona" for the adsorption layer of biomolecules. Soil, as one of the most complex and dynamic environments, contains a diverse array of organic compounds of varying sizes. The soil root zone is particularly active, influenced by factors such as soil composition, plant exudates, and soil microbiota. The molecular diversity and chemical composition of soils can also be modified by the addition of biochar, which alters the nature of soil organic matter. This scenario represents the higher diversity of biomolecules that can be found in soils, which will impact eco-corona formation as well as transformation and fate of nanoparticles. These environments, characterized by complex organic composition, remain underexplored from the eco-corona perspective, representing a significant area of research opportunity. There are many unanswered questions regarding the dominant mechanisms of interaction and resilience of proteins and molecules in more diverse scenarios driving corona formation. The aim of this BEPE project is to understand the composition of eco-corona formed onto CuO nanoparticles within a soil rhizosphere zone using cutting-edge scientific instrumentation for organic matter characterization at the molecular level of detail. We expect to identify an adsorption pattern of molecules that constitute the eco-corona by evaluating soil dissolved organic matter, humic acids, soybean root exudate, and rhizobium extract, varying the sequence and duration of exposure, mixtures, and nanoparticle morphology. By elucidating the composition of eco-corona in different scenarios and addressing both hard and soft corona issues, we aim to bridge significant gaps and uncertainties regarding eco-corona, providing insights that will guide future research on nanomaterials for soil application. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) will be the key technique to explore the organic matter at a molecular-level. Meanwhile, the liquid state 1H nuclear magnetic resonance (NMR) and high-resolution magic angle spinning (HR-MAS) NMR will provide highly resolved spectra (2D-NMR). Together, these techniques enhance our understand of organic matter composition, facilitating a detailed characterization of the molecules that comprise the mediums and eco-corona. Methodologies such as thermochemolysis-gas chromatography/mass spectrometry, using tretramethylammonium hydroxide (TMAH) as a derivatization agent, and the benzenepolycarboxylic acid (BPCA) method as a molecular marker for black carbon, will be employed to assess changes in organic matter resulting from biochar soil addition. Therefore, this BEPE project stands at the frontier of knowledge in environmental nanoscience, particularly regarding soils environment. The techniques outlined are crucial for advancing our understanding of the role of the rhizosphere in eco-corona formation. Dr. Hatcher, a specialist in the proposed techniques, presents us with an opportunity to enhance the discussion and interpretation of the results. His laboratory group is renowned for being one of the leading research teams in chromatography and molecular analysis of complex samples worldwide.