resumo
Magnetic hydrogel kappa-carrageenan nanospheres were successfully prepared via water-in-oil (w/o) microemulsions combined with thermally induced gelation of the polysaccharide. The size of the nanospheres (an average diameter (empty set) of about 50 and 75 nm) was modulated by varying the concentration of surfactant. The nanospheres contained superparamagnetic magnetite nanoparticles (empty set 8 nm), previously prepared by co-precipitation within the biopolymer. Carboxyl groups, at a concentration of about 4 mmol g(-1), were successfully grafted at the surface of these magnetic nanospheres via carboxymethylation of the kappa-carrageenan. The carboxylated nanospheres were shown to be thermo-sensitive in the 37-45 degrees C temperature range, indicating their potential as thermally controlled delivery systems for drugs and/or magnetic particles at physiological temperatures. Finally, preliminary results have been obtained for IgG antibody conjugation of the carboxylated nanospheres and the potential of these systems for bio-applications is discussed.
palavras-chave
DIFFERENTIAL SCANNING CALORIMETRY; IRON-OXIDE NANOPARTICLES; MINIEMULSION POLYMERIZATION; BIOMEDICAL APPLICATIONS; STARCH DERIVATIVES; DRUG-DELIVERY; PARTICLES; FUNCTIONALIZATION; CARBOXYMETHYLATION; MICROGELS
categoria
Science & Technology - Other Topics; Materials Science; Physics
autores
Daniel-da-Silva, AL; Fateixa, S; Guiomar, AJ; Costa, BFO; Silva, NJO; Trindade, T; Goodfellow, BJ; Gil, AM
nossos autores
Ana Luísa Daniel da Silva
Investigador Principal
Ana Maria Pissarra Coelho Gil
Professor Associado com Agregação
Brian James Goodfellow
Professor Auxiliar
Nuno João Silva
Investigador Principal
Sara Fateixa
Bolseiro de pós-Doutoramento
Tito Trindade
Professor CatedráticoGrupos
G1 - Materiais Porosos e Nanossistemas
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G5 - Materiais Biomiméticos, Biológicos e Vivos
agradecimentos
This work was partially funded by FCT and FEDER (project PTDC/QUI/67712/2006). A L Daniel-da-Silva thanks CICECO-Centro de Investigacao em Materiais Ceramicos e Compositos (University of Aveiro, Portugal) and FCT (grant SFRH/BPD/39105/2007) for funding this work. The authors thank Manuel Martins (University of Aveiro, Portugal) for performing TEM observations. The work in Zaragoza has been supported by the research grants MAT200761621 and CONSOLIDER-INGENIO 2010 Program, grant CSD2007/0010 from the Ministry of Education. NJOS acknowledges CSIC for a I3P contract.