Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2015 Mar 5;6:6456. doi: 10.1038/ncomms7456

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2015, Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.

This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

PMC Copyright notice

(a) A schematic representation of the gene loaded carrier. Its biocompatible, contracted, negatively charged form circulates freely in a passive form until extravasation into tumour tissue characterized by lowered pH. Tumour acidosis switches the carriers charge to enhance cellular interaction and uptake. Protonation of the carriers’ amino groups leads to distention of the polymer chains, dilation and expulsion of payloads. Here p53 and KillerRed genes transfect tumour cells. p53 triggers apoptosis while illumination of KillerRed protein generates ROS and subsequent intracellular damage, further promoting cell apoptosis. (b,c) ζ-Potential (b) and hydrodynamic diameter (c) of the DNA-complex and bPEI_25K/DNA-complex as a function of pH for varying bPEI_25K/DNA/copolymer weight ratios. Data show the mean of the measurements conducted in triplicate±s.d. (d) Fluorescence intensity after cellular uptake of the bPEI_25K/DNA-complex (bPEI_25K/DNA weight ratio: 2/1) or DNA-complex (bPEI_25K/DNA/copolymer weight ratio: 0.5/1/1) monitored using Alexa Fluor 488 labelling of plasmid DNAs over the period of several cycles of pH between 7.4 and 6.8 or incubated at only pH 7.4 or 6.8. Results show mean of measurements conducted in triplicate±s.d. Oscillating charge of the carrier results in a step-like response in cellular uptake of the DNA-complex with fluctuating pH.