RESUMEN
A novel kind of chitosan derivatives (CS-LA-TM) were synthesized by grafting hydrophobic molecules of lithocholic acid (LA) and quaternization. CS-LA-TM and micelle-like self-aggregates were characterized by FTIR, 1H NMR, fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy (TEM). The critical micelles concentration (CMC) ranging from 0.009 mg/mL to 0.030 mg/mL decreased with increasing of the degree of substitution (DS) of LA, pH of medium but with decreasing of the degree of quaternization (DQ) of amino groups. The TEM images demonstrated that spherical CS-LA-TM nanoaggregates with uniform size were formed by self-assembly. The sizes (100-200 nm) of CS-LAs-TMs nanoaggregates increased with increasing of DS, DQ, and can be easily controlled by pH of medium, which may confer the nanoaggregates potential as delivery systems for anticancer drugs, or DNA and siRNA.
Asunto(s)
Quitosano/química , Cristalización/métodos , Ácido Litocólico/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Nanotecnología/métodos , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
Objective proteins synthesized from genetically recombined Escherichia coli strain (E. coli) have been successfully produced by microbe fermentation, but complicated separation and purification steps always make against the maintenance of activities as well as increase the cost. Aiming at simplifying the process, an idea of administrating directly the microencapsulated genetically recombined E. coli is proposed. In this paper, study on culture of E. coli DH5 alpha immobilized in alginate/chitosan (ACA) microcapsule is presented. It was found that E. coli DH5 alpha grew well in the microcapsule with stable growth period longer than that of suspension culture, and cell aggregation phenomenon was observed. In vivo experiments showed that ACA microcapsules with E. coli DH5 alpha stayed over 48 h in mouse intestine, and the morphology of microcapsules was kept intact. These preliminary results have demonstrated that administration of microencapsulated E. coli DH5 alpha is safe, which laied the foundation for microencapsulated genetically recombined E. coli as carriers of gene engineering drugs.