科研之友
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摘要
A novel drug delivery system (DDS) based on a carbon nanotube (CNT)poly(3,4-ethylenedioxythiophene) (PEDOT) composite was constructed via a layering method. Single-walled CNTs (SWNTs) were immobilized on a gold electrode using a layer-by-layer technique. In particular, cysteamine (Cys) was firstly bonded to the gold surface through the strong S-Au association and SWNTs were subsequently linked onto the Cys layer through condensation reaction of -NH2 and carboxyl groups by 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide coupling. X-ray photoelectron spectroscopy and Raman spectroscopy demonstrate that this is a facile route for immobilizing CNTs on gold electrodes. Finally PEDOT was electropolymerized on the SWNT-functionalized electrode to make a SWNT-PEDOT composite, and the modified electrode was applied as a DDS. Dexamethasone, as a model drug, was incorporated into PEDOT in the electropolymerization. Investigations of the electrochemical properties of SWNT-PEDOT demonstrate that SWNTs greatly improve the conductivity and increase the charge capacity of PEDOT. The composite exhibits a petal-like surface structure, 20-30 nm thick and 100-200 nm wide. Compared to a DDS based on pure PEDOT synthesized under the same conditions, SWNT-PEDOT has the merits of higher drug release rate and larger release amount. The average mass release for every five voltammetry cycles increases from 1.4126 to 1.8864 mg cm(-2).
