Marcos Antonio Sabino Gutiérrez , Doutor em Química, mestre em Engenharia de Materiais e graduado em Química de Polímeros pela Universidade Simón Bolívar (USB), Caracas-Venezuela. É pesquisador chefe do Grupo de Pesquisa B5IDA (Biomateriais, Biomiméticos, Biopolímeros, Biodegradáveis e Biocompatíveis). É atualmente, por dois meses, Pesquisador Visitante no Centro de Tecnologia da Informação Renato Archer (CTI), onde também já esteve como pesquisador visitante pela FAPESP e CNPq anteriormente. Desenvolveu trabalhos de pesquisa em Biopolímeros no Instituto de Pesquisa Francês INRA e na Universidade do Minho, onde realizou um Pós-Doutoramento em cada instituição.
Marcos Antonio Sabino Gutiérrez
Grupo B5IDA, Departamento de Química, Universidad Simón Bolivar, Caracas, Venezuela
Núcleo de Tecnologias Tridimensionais, Centro de Tecnologia da Informação Renato Archer (CTI), Campinas, SP, Brasil
Biopolymers such as polysaccharides are compounds that possess functional groups that are very susceptible to be used to make chemical modifications and to extend their applications. And, this allows them to be used as graft-like chains for the synthesis of new copolymers with characteristics of biomaterials. Poly (N-Isopropylacrylamide) PNIPA, is a thermosensitive synthetic polymer widely used in the preparation of intelligent gels for the biomedical field. In this research the synthesis and characterization of graft copolymers based on PNIPA with the biopolymers: chitosan (QN), hyaluronic acid (HA) and alginate (ALG) were performed, which obtain new biodegradable and biocompatible biomaterials, and maintain their intelligent character due to the phase change as a result of their thermosensitivity. The PNIPA was in first time chemically modified with 3-butenoic acid in order to generate carboxyl end groups on the copolymer chain (PNIPA-co-COOH) which serve as anchor points and then covalently graft the polysaccharides. For the specific case of the graft with hyaluronic acid, it was necessary to perform a second modification using piperazine (PIP) and obtain copolymers of type PNIPA-co-COO-g-PIP. The polysaccharides used as grafts were: (1) chitosan oligomers obtained by acid degradation; (2) commercial sample of hyaluronic acid and (3) purified alginate. The characterization of all copolymers obtained consisted of conducting infrared spectroscopic studies. The differential scanning calorimetry technique was used to determine the lower critical solution temperature or LCST transition, resulting in the range of 29-34 °C. After simulating an injectability process (for the gel character presented by these novel copolymers) its morphology was studied using scanning electron microscopy, resulting in the presence of ordered scaffold-like micrometric structures with high porosity and interconnection between pores. Hemocompatibility assays were performed on agar/blood systems, showing the most of these formulations being biocompatible. It was also possible to obtain micro/nano particles, and depending on the structure of each copolymer, particles or capsules could be obtained. All these results give these copolymers a high potentiality of use in tissue engineering and for pharmacological applications.