An electric field responsive drug delivery system based on chitosan–gold nanocomposites for site specific and controlled delivery of 5-fluorouracil†
Abstract
A novel drug delivery system based on an electric field and pH dual-stimuli responsive chitosan–gold nanocomposite (CGNC) is reported in the present study for site specific controlled delivery of the anticancer drug 5-fluorouracil (5-FU). At a higher pH of the solution CGNC encapsulates the drug molecules in its 3D-network and releases the drug at a relatively lower pH due to its reversible gel–sol transition properties. A sulphorhodamine B cytotoxicity assay showed that the chitosan–gold nanocomposite–fluorouracil conjugate (CGNC–FU) has higher cytotoxicity than 5-FU to the cervical cancer cells, SiHa. Drug release from CGNC has been controlled by applying a weak, external DC electric field. The drug delivery system is illustrated to be effective for the loading and delivery of 5-FU. The encapsulation efficiency of CGNC was found to be 36% and about 63% of the drug was released by applying the electric field. The biocompatibility of CGNC was demonstrated by growing SiHa cells successfully on a CGNC film electrodeposited on an indium tin oxide (ITO) coated glass plate. SiHa cells grown on a CGNC–FU conjugate modified ITO plate showed less viability and further application of an electric field of 1.5 V for the release of 5-FU led to the complete death of the cells. A highlight of the present drug delivery system is that the drug release can be controlled externally.