resumo
The release of DNA from cryogel PVA-DNA gel matrices to different electrolyte aqueous solutions was investigated. The rate of release and the distribution coefficient of DNA have been quantified by using a first order kinetic law equation, developed in the frame of a partition-based model. The release of DNA from gels to 1:1 sodium and nitrate salts shows that the transport properties are dependent on the ability of anions/cations to solubilise the DNA in the aqueous phase which, with the exception of bromide, can be related to the Hofmeister series; in the presence of multivalent electrolytes, or increasing the ionic strength, the condensation of DNA inside the gel, followed by a phase separation as seen by scanning electron microscopy, induces the retention of DNA inside the polymer matrix. The DNA condensation and/or phase separation, which contribute to a decrease in the water volume fraction inside the gel, determined by swelling degree experiments, also lead to a decrease in the rate constant of DNA release; such decrease can be justified by the difficulty of the molecular aggregate to move through out the polymeric structure. The DNA release is also dependent on the pH of the bulk solution. The effect of uni- and di-valent cationic surfactants on the release properties of DNA was also evaluated. Our findings suggest that the kinetics of DNA release depends on a complex balance between different structural properties of the surfactants, namely charge, bulkiness of the headgroup and alkyl chain length. (C) 2012 Elsevier B.V. All rights reserved.
palavras-chave
DRUG-DELIVERY; SWELLING EQUILIBRIA; POLY(VINYL ALCOHOL); GENE DELIVERY; STRANDED-DNA; POLYMER GELS; PLASMID DNA; HYDROGELS; PVA; TRANSFECTION
categoria
Biophysics; Chemistry; Materials Science
autores
Valente, AJM; Cruz, SMA; Murtinho, DMB; Miguel, MG; Muniz, EC
nossos autores
Sandra Maria Alves da Cruz
Estudante de doutoramentoGrupos
agradecimentos
We are grateful to Prof. Bjorn Lindman for his valuable comments on this paper. Financial support from Fundacao para a Ciencia e Tecnologia (Project PTDC/QUI/67962/2006) is gratefully acknowledged.