Márcio José Tiera

Universidade Estadual Paulista (Unesp)

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Vera Aparecida de Oliveira Tiera

Universidade Estadual Paulista (Unesp)

Julio Fernandes

Hôpital du Sacré-Cœur de Montréal

Aline Margarete Furuyama Lima

Universidade Estadual Paulista (Unesp)

Miguel G. Neumann

Universidade Federal de São Carlos

André Miguel Martinez

Universidade Estadual Paulista (Unesp)

Vera Aparecida de Oliveira Tiera

Universidade Estadual Paulista (Unesp)

Qin Shi

Fuzhou Pulmonary Hospital of Fujian

Françoise M. Winnik

National Institute for Materials Science

Isadora Pfeifer Dalla Picola

Universidade Estadual Paulista (Unesp)

Maicon Segalla Petrônio

Universidade Estadual Paulista (Unesp)

Cooperative Institutions

Universidade Estadual Paulista (Unesp)

238

Universidade de São Paulo

Hospital Regional de Presidente Prudente

Universidade Estadual de Campinas (UNICAMP)

Faculdade de Tecnologia e Ciências

Universidade Federal de São Carlos

Universidade de Marília

Hôpital du Sacré-Cœur de Montréal

Université de Montréal

Faculdade de Medicina de São José do Rio Preto

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Polycation-Based Gene Therapy: Current Knowledge and New Perspectives

Current Gene Therapy (2011)

Márcio José Tiera Qin Shi Françoise M. Winnik Julio Fernandes

At present, gene transfection insufficient efficiency is a major drawback of non-viral gene therapy. The 2 main types of delivery systems deployed in gene therapy are based on viral or non-viral gene carriers. Several non-viral modalities can transfer foreign genetic material into the human body. To do so, polycation-based gene delivery methods must achieve sufficient efficiency in the transportation of therapeutic genes across various extracellular and intracellular barriers. These barriers include interactions with blood components, vascular endothelial cells and uptake by the reticuloendothelial system. Furthermore, the degradation of therapeutic DNA by serum nucleases is a potential obstacle for functional delivery to target cells. Cationic polymers constitute one of the most promising approaches to the use of viral vectors for gene therapy. A better understanding of the mechanisms by which DNA can escape from endosomes and traffic to enter the nucleus has triggered new strategies of synthesis and has revitalized research into new polycation-based systems. The objective of this review is to address the state of the art in gene therapy with synthetic and natural polycations and the latest advances to improve gene transfer efficiency in cells.

10.2174/156652311796150408

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Citations (100)

Synthesis, characterization and solution properties of amphiphilic N-isopropylacrylamide–poly(ethylene glycol)–dodecyl methacrylate thermosensitive polymers

Colloids and Surfaces A Physicochemical and Engineering Aspects (2005)

Neide Aparecida Blaz Vieira João Ruggiero Neto Márcio José Tiera

Gel permeation chromatography

Hydrodynamic radius

Cloud point

10.1016/j.colsurfa.2005.05.006

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Citations (18)

Hydrophobic Effect of Amphiphilic Derivatives of Chitosan on the Antifungal Activity against Aspergillus flavus and Aspergillus parasiticus

Molecules (2013)

Ricchard Viegas de Souza Mirelli Takaki Rafael de Oliveira Pedro Juliana dos Santos Gabriel Márcio José Tiera

Low molecular weight amphiphilic derivatives of chitosan were synthesized, characterized and their antifungal activities against Aspergillus flavus and Aspergillus parasiticus were tested. The derivatives were synthesized using as starting material a deacetylated chitosan sample in a two step process: the reaction with propyltrimethyl-ammonium bromide (Pr), followed by reductive amination with dodecyl aldehyde. Aiming to evaluate the effect of the hydrophobic modification of the derivatives on the antifungal activity against the pathogens, the degree of substitution (DS₁) by Pr groups was kept constant and the proportion of dodecyl (Dod) groups was varied from 7 to 29% (DS₂). The derivatives were characterized by ¹H-NMR and FTIR and their antifungal activities against the pathogens were tested by the radial growth of the colony and minimum inhibitory concentration (MIC) methods. The derivatives substituted with only Pr groups exhibited modest inhibition against A. flavus and A. parasiticus, like that obtained with deacetylated chitosan. Results revealed that the amphiphilic derivatives grafted with Dod groups exhibited increasing inhibition indexes, depending on polymer concentration and hydrophobic content. At 0.6 g/L, all amphiphilic derivatives having from 7.0 to 29% of Dod groups completely inhibited fungal growth and the MIC values were found to decrease from 4.0 g/L for deacetylated chitosan to 0.25-0.50 g/L for the derivatives. These new derivatives open up the possibility of new applications and avenues to develop effective biofungicides based on chitosan.

Aspergillus parasiticus

10.3390/molecules18044437

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Citations (24)

Energy transfer between anthracene bound to pmaa and basic dyes

Abstracts (1992)

Márcio José Tiera Miguel G. Neumann Carlos M. Previtali

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Polymeric Systems as Nanodevices for siRNA Delivery

Current Gene Therapy (2013)

Márcio José Tiera Qin Shi Hellen Franciane Gonçalves Barbosa Julio Fernandes

The delivery of small interfering RNAs (siRNAs) is a promising approach to silencing gene expression aimed at treating infections, cancer, neurodegenerative diseases and various other disorders. Recent progress in this area has been achieved with nanodevices possessing multiple properties and assembled with new, biodegradable, synthetic polymers and polysaccharides. Different synthetic routes and multiple strategies, such as multilayer systems and stimuliresponsive polymers, have been developed to attain high efficiencies. This review covers the most important, promising and successful approaches to improve siRNA delivery. It is a concise report on multiple strategies employed, including cell-specific delivery coupling ligands or antibodies with nanodevices to improve siRNA efficiency and specificity.

10.2174/156652321305131212125042

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Citations (9)

Biopolymeric Films of Amphiphilic Derivatives of Chitosan: A Physicochemical Characterization and Antifungal Study

International Journal of Molecular Sciences (2019)

Anna Carolina Rodrigues Santos Alves Aline Margarete Furuyama Lima Márcio José Tiera Vera Aparecida de Oliveira Tiera

The chemical modification of chitosan has been an active subject of research in order to improve the physicochemical and antifungal properties of chitosan-based films. The aim of this study was to evaluate the physiochemical and antifungal properties of films prepared with chitosan and its derivatives containing diethylaminoethyl (DEAE) and dodecyl groups (Dod). Chitosans and selected derivatives were synthesized and characterized, and their films blended with glycerol and sorbitol (5%, 10%, and 20%). They were studied by means of the evaluation of their mechanical, thermal, barrier, and antifungal properties. The collected data showed that molecular weight (Mw), degree of acetylation, and grafting with DEAE and Dod groups greatly affected the mechanical, thickness, color, and barrier properties, all of which could be tailored by the plasticizer percentage. The antifungal study against Aspergillus flavus, Alternaria alternata, Alternaria solani, and Penicillium expansum showed that the films containing DEAE and Dod groups exhibited higher antifungal activity than the non-modified chitosans. The mechanical properties of highly soluble films were improved by the plasticizers at percentages of 5% and 10%, indicating these derivatives as potential candidates for the coating of seeds, nuts and fruits of various crops.

Plasticizer

Biopolymer

Alternaria solani

10.3390/ijms20174173

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Citations (12)

Topical delivery of siRNA to psoriatic skin model using high molecular weight chitosan derivatives: In vitro and in vivo studies

Drug Delivery and Translational Research (2025)

André Miguel Martinez Thalles Fernando Rocha Ruiz Patrícia Simone Leite Vilamaior Vera Aparecida de Oliveira Tiera Sebastião Roberto Taboga

10.1007/s13346-025-01800-4

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