Marcelo Assis

Valencia Catholic University Saint Vincent Martyr

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Document Type

Co-Authors

E. Longo

Universidade Federal de São Carlos

105

Juán Andrés

Universitat Jaume I

Lara Kelly Ribeiro

Universidade Federal de São Carlos

Amanda F. Gouveia

Universitat Jaume I

Lúcia H. Mascaro

Universidade Federal de São Carlos

Camila Cristina de Foggi

Universidade Federal do Rio Grande do Sul

Ieda L. V. Rosa

Universidade Federal de São Carlos

Fernanda de Freitas Aníbal

Universidade Federal de São Carlos

Carlos Eduardo Vergani

Universidade Estadual Paulista (Unesp)

Lourdes Gracia

Hospital General Universitario de Alicante Doctor Balmis

Cooperative Institutions

Universidade Federal de São Carlos

181

Universidade de São Paulo

Universidade Estadual Paulista (Unesp)

Universitat Jaume I

Centro Universitário de Araraquara

Universidade Federal de São Paulo

Universidade Estadual de Campinas (UNICAMP)

Universidade Federal do Maranhão

Universitat de València

Universidade Federal de Alfenas

Author Statistics

Papers

Citation

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Research Field

Mechanism of photoluminescence in intrinsically disordered CaZrO3 crystals: First principles modeling of the excited electronic states

Journal of Alloys and Compounds (2017)

Marisa C. Oliveira Lourdes Gracia Marcelo Assis Ieda L. V. Rosa Maria Fernanda do Carmo Gurgel

10.1016/j.jallcom.2017.06.052

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Citations (23)

Gold Nanoparticles: In Vivo and in Vitro Toxicity, Cell Proliferation, Cell Gene Expression and Antiviral Activity Against a Surrogate of SARS-CoV-2

SSRN Electronic Journal (2022)

Beatriz Salesa Patricia Ferrús-Manzano Alberto Tuñón-Molina Alba Cano-Vicent Marcelo Assis

Gold nanoparticles (AuNPs) are a fundamental building block of many applications across nanotechnology as they have excellent antibacterial efficacy and biosafety which make them promising for a broad range of biomedical applications. Here we explore their in vivo toxicity, cytotoxicity and proliferative capacity in human keratinocyte cells, their ability to induce gene expression in a wide range of genes and their antiviral properties against a surrogate of SARS-CoV-2. The results showed that AuNPs are non-toxic in vivo at any concentration up to 800 µg/mL. However, AuNP cytotoxicity in human HaCaT cells is time-dependent, so that concentrations of up to 300 µg/mL did not show any in vitro toxic effect at 3, 12 and 24 h, although higher concentrations were found to have some significant toxic activity, especially at 24 h. No significant proliferative activity was observed when using low AuNP concentrations (10, 20 and 40 μg/mL), while the AuNP antiviral tests indicated low or insignificant antiviral activity. Surprisingly, none of the 13 analyzed genes had their expressions modified after 24 h's exposure to AuNPs. These results have an essential value in the strategy for treating bacterial and viral infections of general interest in different fields of biomedicine, plus antiviral activity against a surrogate of SARS-CoV-2, Influenza or Ebola. We expect further research to broaden the field of AuNP applications and accelerate their transfer to biomedicine and clinical applications.

10.2139/ssrn.4255400

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Citations (0)

PVC-SiO2-Ag composite as a powerful biocide and anti-SARS-CoV-2 material

Journal of Polymer Research (2021)

Marcelo Assis Luiz Gustavo Pagotto Simões Guilherme C. Tremiliosi Lara Kelly Ribeiro Dyovani Coelho

The ongoing COVID-19 pandemic has pushed scientists and technologists to find novel strategies to develop new materials to prevent the transmission, spread, and entry of pathogens into the human body. In this report, the fabrication of polyvinyl chloride (PVC)-SiO2-Ag composite is presented, in which the percentage of Ag is 0.84% wt. Our findings render that this composite eliminates (> 99.8%) bacteria and fungus (Staphylococcus aureus, Escherichia coli, Penicillium funiculosum) and SARS-CoV-2, by surface contact in 2 h hours and 15 min, respectively. Specific migration analysis shown that the use of the PVC-SiO2-Ag composite is considered safe and effective for food preservation. This research and innovation front can be considered a breakthrough for the design of biocide materials. Future directions for this exciting and highly significant research field can open the door to the development of new technologies for the fabrication of packaging films to protect consumer products (such as fruits, vegetables, and other foods).

Biocide

10.1007/s10965-021-02729-1

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Citations (19)

Development and Characterization of Electrospun Nanostructures Using Polyethylene Oxide: Potential Means for Incorporation of Bioactive Compounds

Colloids and Interfaces (2020)

Sergiana dos Passos Ramos Michele Amendoeira Giaconia Jonas T. Do Marco Robert Paiva Veridiana Vera de Rosso

The development of processes for stabilization of the properties of bioactive compounds has been studied in recent years, and the use of nanotechnology is among the most discussed routes. The present work addressed the assembly of nanostructures using polyethylene oxide (PEO), the production of core-shell nanofibers (NFs) with bioactive compounds, and the evaluation of their microscopic and physical characteristics. Aqueous solutions of PEO were electrospun by varying different process and solution parameters (PEO and NaCl concentrations, feeding rate, the tip-to-collector distance (TCD), and applied voltage) in order to optimize production of nanostructures. The best condition obtained was evaluated to form core-shell NFs composed by jussara pulp as a source of anthocyanins. To assess the production of NFs with PEO and jussara pulp, feed solutions were prepared in acetate buffer (pH 4.5) with 6% PEO and 10% lyophilized jussara pulp, at a feeding rate of 150 μL·h−1 and TCD of 15 cm using an applied voltage of 10 kV to form core-shell NFs. The results revealed the formation of core-shell NFs with a diameter of 126.5 ± 50.0 nm. The outcomes achieved represent a crucial step in the application of anthocyanins in food systems as pigments, establishing a basis for further research on the incorporation of nanomaterials into foodstuff.

Nanomaterials

Polyethylene oxide

10.3390/colloids4020014

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Citations (18)

Efficient photoelectrochemical real textile wastewater detoxification using photoanodes of C3N4–BiVO4

Chemosphere (2024)

Isabelle M.D. Gonzaga Roger Gonçalves Carlos H.M. Fernandes Marcelo Assis Ivo F. Teixeira

Bismuth vanadate

Graphitic carbon nitride

Industrial wastewater treatment

Textile industry

Charge carrier

10.1016/j.chemosphere.2024.141315

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Citations (4)

Electron beam irradiation for the formation of thick Ag film on Ag₃PO₄

RSC Advances (2020)

João Paulo de Campos da Costa Marcelo Assis Vinícius Teodoro André Rodrigues-Pinheiro Camila Cristina de Foggi

This study demonstrates that the electron beam irradiation of materials, typically used in characterization measurements, could be employed for advanced fabrication, modification, and functionalization of composites. We developed irradiation equipment using an electron beam irradiation source to be applied in materials modification. Using this equipment, the formation of a thick Ag film on the Ag3PO4 semiconductor is carried out by electron beam irradiation for the first time. This is confirmed by various experimental techniques (X-ray diffraction, field-emission scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy) and ab initio molecular dynamics simulations. Our calculations demonstrate that, at the earlier stages, metallic Ag growth is initiated preferentially at the (110) surface, with the reduction of surface Ag cations forming metallic Ag clusters. As the (100) and (111) surfaces have smaller numbers of exposed Ag cations, the reductions on these surfaces are slower and are accompanied by the formation of O2 molecules.

Electron beam processing

Surface Modification

10.1039/d0ra03179h

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Citations (14)

Fermented Jussara: Evaluation of Nanostructure Formation, Bioaccessibility, and Antioxidant Activity

Frontiers in Bioengineering and Biotechnology (2022)

Michele Amendoeira Giaconia Sergiana dos Passos Ramos Camilly Fratelli Marcelo Assis Tatiana Martelli Mazzo

Among the species of plants present in the Atlantic Forest, the jussara (Euterpe edulis Mart.) stands out for the contents of bioactive compounds present in its composition. Fermentation processes can be essential in converting bioproducts and bioactive compounds, improving their biological properties. In addition, the improvement of procedures for the maintenance of the features of bioactive compounds has been a research focus in recent years, and the nanotechnology features that can potentially solve this issue have been highlighted among the most reviewed paths. The present work focused on tailoring nanostructures applying polyethylene oxide, assembling fermented jussara pulp nanofibers, and assessing their characteristics. The results revealed the formation of fermented jussara nanofibers with a diameter of 101.2 ± 26.2 nm. Also, the obtained results allow us to state that it is possible to maintain or even increase the antioxidant activity of anthocyanins and their metabolites after fermentation processes.

Bioproducts

10.3389/fbioe.2022.814466

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Citations (10)

Study of biological properties of gold nanoparticles: Low toxicity, no proliferative activity, no ability to induce cell gene expression and no antiviral activity

Chemico-Biological Interactions (2023)

Beatriz Salesa Patricia Ferrús-Manzano Alberto Tuñón-Molina Alba Cano-Vicent Marcelo Assis

HaCaT

Nanotoxicology

Zeta potential

10.1016/j.cbi.2023.110646

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Citations (7)

Design Ag-Based Semiconductors for Antimicrobial Technologies: Challenges and Future Trends

Anna Rafaela Cavalcante Braga Letícia G. da Trindade Sonia Ramos Monize Bürck Monica Masako Nakamoto

Semiconductors are one of the most versatile materials found today and are applied in various fields of technology. Currently, one of the applications gaining significant recognition is their use as antimicrobial agents. Unlike other organic antimicrobial agents like antibiotics and antifungal drugs, semiconductors have different mechanisms of action. Silver (Ag) has been prominent since ancient times due to its ability for ionic release, interaction with organic groups based on phosphorus and sulfur, and plasmonic effect among the primary materials used for microbial elimination. As a result, not only Ag-based nanoparticles are highly efficient in inactivating pathogens, but also Ag-based semiconductors are extensively utilized for this purpose. This work focuses on studying the design of Ag-based semiconductors, including Ag2O, AgVO3, Ag2WO4, Ag2CrO4, Ag2MoO4, and Ag3PO4, along with their intrinsic antimicrobial activity. Additionally, it explores new perspectives and future trends in applying these materials.

10.1007/978-981-97-0221-3_11

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Citations (1)

Tailoring the Bactericidal Activity of Ag Nanoparticles/α-Ag₂WO₄Composite Induced by Electron Beam and Femtosecond Laser Irradiation: Integration of Experiment and Computational Modeling

ACS Applied Bio Materials (2019)

Nadia G. Macedo Thales R. Machado Román Alvarez Roca Marcelo Assis Camila Cristina de Foggi

In nanotechnology research, significant effort is devoted to fabricating patterns of metallic nanoparticles on the surfaces of different semiconductors to find innovative materials with favorable characteristics, such as antimicrobial and photocatalytic properties, for novel applications. We present experimental and computational progress, involving a combined approach, on the antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) of as-synthesized α-Ag2WO4 samples and Ag nanoparticle composites (Ag NPs)/α-Ag2WO4. The former included two morphologies: hexagonal rod-like (α-Ag2WO4-R) and cuboid-like (α-Ag2WO4-C), and the latter included composites formed under electron beam, Ag NPs/α-Ag2WO4-RE and Ag NPs/α-Ag2WO4-CE, and femtosecond (fs) laser irradiation, Ag NPs/α-Ag2WO4-RL and Ag NPs/α-Ag2WO4-CL. Direct observations of the arrangement of Ag NPs on the Ag NPs/α-Ag2WO4 composites irradiated with an electron beam and laser, through transmission electron microscopy (TEM), high-resolution TEM, energy-dispersive X-ray spectroscopy, and field-emission scanning electron microscopy, allow us to investigate the surface morphology, chemical composition, homogeneity, and crystallinity. Therefore, these experimental factors, and in particular, the facet-dependent response of Ag NPs/α-Ag2WO4 composites were discussed and analyzed from the perspective provided by the results obtained by first-principles calculations. On this basis, α-Ag2WO4-R material proved to be a better bactericidal agent than α-Ag2WO4-C with minimum bactericidal concentration (MBC) values of 128 and 256 μg/mL, respectively. However, the Ag NPs/α-Ag2WO4-CL composite is the most efficient bactericidal agent of all tested samples (MBC = 4 μg/mL). This superior performance can be attributed to the cooperative effects of crystal facets and defect engineering. These results on the synthesis and stability of the Ag NPs/α-Ag2WO4 composites can be used for the development of highly efficient bactericidal agents for use in environmental remediation and the potential extension of methods to produce materials with catalytic applications.

10.1021/acsabm.8b00673

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Citations (37)