pH-Responsive Graphene Oxide-DNA Nanosystem for Live Cell Imaging and Detection

Area of Science:

• Biomaterials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Graphene oxide (GO) interaction with DNA is pH-dependent, limiting biosensor sensitivity.
• Acidic conditions enhance GO-DNA affinity, reducing conformational discrimination.
• This challenge impedes the development of reliable GO-DNA based pH biosensors.

Purpose of the Study:

• To investigate the pH-dependent affinity between GO and i-motif forming oligonucleotides (IFOs).
• To develop a method to overcome the pH sensitivity limitations in GO-DNA nanosystems.
• To create a robust pH biosensor for both in vitro and intracellular applications.

Main Methods:

• Systematic study of GO-IFOs affinity across various pH levels.
• Development of a herring sperm DNA (HSD) treatment for GO surface modification.
• Fabrication and testing of a novel pH-sensitive GO-IFO nanosystem.

Main Results:

• HSD treatment successfully mitigates the enhanced GO-DNA affinity under acidic conditions.
• The GO-IFO nanosystem demonstrated improved discrimination between 'open' and 'closed' IFO conformations over a broader pH range.
• The developed nanosystem exhibited excellent sensing capabilities for both in vitro and intracellular pH detection.

Conclusions:

• The HSD treatment strategy effectively enhances the pH tolerance of GO-DNA nanosystems.
• This approach significantly improves the performance of GO-based biosensors for pH monitoring.
• The developed method holds broad potential for various GO-DNA sensing applications beyond pH detection.