Milena T. Pelegrino

Bio: Milena T. Pelegrino is an academic researcher from Universidade Federal do ABC. The author has contributed to research in topics: Nanocarriers & Drought tolerance. The author has an hindex of 15, co-authored 41 publications receiving 820 citations. Previous affiliations of Milena T. Pelegrino include Federal University of São Paulo & State University of Campinas.

Exogenous nitric oxide improves sugarcane growth and photosynthesis under water deficit.

Abstract: Nitric oxide (NO)-mediated redox signaling plays a role in alleviating the negative impact of water stress in sugarcane plants by improving root growth and photosynthesis. Drought is an environmental limitation affecting sugarcane growth and yield. The redox-active molecule nitric oxide (NO) is known to modulate plant responses to stressful conditions. NO may react with glutathione (GSH) to form S-nitrosoglutathione (GSNO), which is considered the main reservoir of NO in cells. Here, we investigate the role of NO in alleviating the effects of water deficit on growth and photosynthesis of sugarcane plants. Well-hydrated plants were compared to plants under drought and sprayed with mock (water) or GSNO at concentrations ranging from 10 to 1000 μM. Leaf GSNO sprayed plants showed significant improvement of relative water content and leaf and root dry matter under drought compared to mock-sprayed plants. Additionally, plants sprayed with GSNO (≥ 100 μM) showed higher leaf gas exchange and photochemical activity as compared to mock-sprayed plants under water deficit and after rehydration. Surprisingly, a raise in the total S-nitrosothiols content was observed in leaves sprayed with GSH or GSNO, suggesting a long-term role of NO-mediated responses to water deficit. Experiments with leaf discs fumigated with NO gas also suggested a role of NO in drought tolerance of sugarcane plants. Overall, our data indicate that the NO-mediated redox signaling plays a role in alleviating the negative effects of water stress in sugarcane plants by protecting the photosynthetic apparatus and improving shoot and root growth.

Superparamagnetic iron oxide nanoparticles dispersed in Pluronic F127 hydrogel: potential uses in topical applications

Abstract: The present study is focused on the synthesis and characterization of nitric oxide (NO)-releasing superparamagnetic iron oxide nanoparticles (Fe3O4 NPs), and their incorporation in Pluronic F127 hydrogel with great potential for topical applications. Magnetite nanoparticles (Fe3O4 NPs) were synthesized by thermal decomposition of acetylacetonate iron (Fe(acac)3), and coated with the thiol containing molecule mercaptosuccinic acid (MSA), leading to Fe3O4-MSA NPs. The obtained NPs were characterized using different techniques. The results showed that the Fe3O4-MSA NPs have a mean diameter of 11 nm, in the solid state, and superparamagnetic behavior at room temperature. Fe3O4-MSA NPs have an average hydrodynamic size of (78.0 ± 0.9) nm, average size distribution (PDI) of 0.302 ± 0.04, and zeta potential of (−22.10 ± 0.55) mV. Free thiol groups on the Fe3O4-MSA NP surface were nitrosated by the addition of sodium nitrite, yielding S-nitrosated magnetic nanoparticles (Fe3O4-S-nitroso-MSA NPs), which act as spontaneous NO donors upon S–N bond cleavage. The amount of (86.4 ± 4.7) μmol of NO was released per gram of Fe3O4-S-nitroso-MSA NPs. In order to enhance NP dispersion, Fe3O4-MSA NPs were incorporated in Pluronic F127 hydrogel (3.4% w/w), and characterized using different techniques. Rheological measurements suggest a potential use for Fe3O4-MSA NPs dispersed in Pluronic hydrogel for topical applications. Atomic force microscopy (AFM) showed that the NPs are embedded within the Pluronic film while the X-ray photoelectron spectroscopy (XPS) spectrum of the Fe3O4-MSA NPs samples revealed the presence of iron, oxygen, carbon and sulfur, confirming the presence of MSA molecules on the NP surface.

Green Synthesis of Metallic Nanoparticles and Their Prospective Biotechnological Applications: an Overview

Abstract: The green synthesis of nanoparticles (NPs) using living cells is a promising and novelty tool in bionanotechnology. Chemical and physical methods are used to synthesize NPs; however, biological methods are preferred due to its eco-friendly, clean, safe, cost-effective, easy, and effective sources for high productivity and purity. High pressure or temperature is not required for the green synthesis of NPs, and the use of toxic and hazardous substances and the addition of external reducing, stabilizing, or capping agents are avoided. Intra- or extracellular biosynthesis of NPs can be achieved by numerous biological entities including bacteria, fungi, yeast, algae, actinomycetes, and plant extracts. Recently, numerous methods are used to increase the productivity of nanoparticles with variable size, shape, and stability. The different mechanical, optical, magnetic, and chemical properties of NPs have been related to their shape, size, surface charge, and surface area. Detection and characterization of biosynthesized NPs are conducted using different techniques such as UV-vis spectroscopy, FT-IR, TEM, SEM, AFM, DLS, XRD, zeta potential analyses, etc. NPs synthesized by the green approach can be incorporated into different biotechnological fields as antimicrobial, antitumor, and antioxidant agents; as a control for phytopathogens; and as bioremediative factors, and they are also used in the food and textile industries, in smart agriculture, and in wastewater treatment. This review will address biological entities that can be used for the green synthesis of NPs and their prospects for biotechnological applications.

Opportunities and challenges for nanotechnology in the agri-tech revolution.

Abstract: Current agricultural practices, developed during the green revolution, are becoming unsustainable, especially in the face of climate change and growing populations. Nanotechnology will be an important driver for the impending agri-tech revolution that promises a more sustainable, efficient and resilient agricultural system, while promoting food security. Here, we present the most promising new opportunities and approaches for the application of nanotechnology to improve the use efficiency of necessary inputs (light, water, soil) for crop agriculture, and for better managing biotic and abiotic stress. Potential development and implementation barriers are discussed, emphasizing the need for a systems approach to designing proposed nanotechnologies.