Issue 14, 2015

pH-Assisted control over the binding and relocation of an acridine guest between a macrocyclic nanocarrier and natural DNA

Abstract

The differential binding affinity of the hydroxypropyl-β-cyclodextrin (HPβCD) macrocycle, a drug delivery vehicle, towards the protonated and deprotonated forms of the well-known DNA binder and model anticancer drug acridine has been exploited as a strategy for dye–drug transportation and pH-responsive delivery to a natural DNA target. From pH-sensitive changes in the ground state absorption and steady-state fluorescence characteristics of the studied acridine dye–HPβCD–DNA ternary system and strongly supported by fluorescence lifetime, fluorescence anisotropy, Job's plots, 1H NMR and circular dichroism results, it is revealed that in a moderately alkaline solution (pH ∼ 8.5), the dye can be predominantly bound to the HPβCD macrocycle and when the pH is lowered to a moderately acidic region (pH ∼ 4), the dye efficiently detaches from the HPβCD cavity and almost exclusively binds to DNA. In the present study we are thus able to construct a pH-sensitive supramolecular assembly where pH acts as a simple stimulus for controlled uptake and targeted release of the dye–drug. As pH is an essential and sensitive factor in various biological processes, a simple yet reliable pH-sensitive model such as is demonstrated here can have promising applications in the host-assisted delivery of prodrug to the target sites, such as cancer or tumour microenvironments, with an enhanced stability, bioavailability and activity, and also in the design of new fluorescent probes, sensors and smart materials for applications in nano-science.

Graphical abstract: pH-Assisted control over the binding and relocation of an acridine guest between a macrocyclic nanocarrier and natural DNA

Supplementary files

Article information

Article type
Paper
Submitted
17 Nov 2014
Accepted
22 Feb 2015
First published
26 Feb 2015
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2015,17, 9519-9532

Author version available

pH-Assisted control over the binding and relocation of an acridine guest between a macrocyclic nanocarrier and natural DNA

M. Sayed and H. Pal, Phys. Chem. Chem. Phys., 2015, 17, 9519 DOI: 10.1039/C4CP05335D

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