Dual Photo- and pH-Responsive Spirooxazine-Functionalized Dextran Nanoparticles

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Developing smart materials with tunable properties is crucial for advanced applications.
• Stimuli-responsive polymers offer dynamic control over material behavior.
• Dextran-based nanomaterials are biocompatible and versatile platforms.

Purpose of the Study:

• To synthesize and characterize dual photo- and pH-responsive spirooxazine-functionalized dextran nanoparticles.
• To investigate the nanoparticle's structural and aggregation behavior under UV light and acidic conditions.
• To evaluate the potential of these nanoparticles for controlled drug delivery using Nile Red as a model drug.

Main Methods:

• Functionalization of dextran with a spirooxazine derivative (SO-COOH).
• Formation of nanoparticles in aqueous media.
• Stimulation studies using UV light, visible light, and varying pH conditions (pH 5 and 3).
• Encapsulation and tracking of Nile Red fluorescent dye to monitor structural changes.

Main Results:

• Successfully synthesized spirooxazine-functionalized dextran (Dex-SO) nanoparticles.
• Demonstrated reversible nanoparticle aggregation upon UV light (forming Dex-MC) and visible light stimuli.
• Observed nanoparticle aggregation and swelling at pH 5 and 3, respectively, due to spirooxazine protonation.
• Nile Red encapsulation provided insights into light- and pH-induced structural transformations.

Conclusions:

• The developed Dex-SO nanoparticles exhibit dual responsiveness to light and pH.
• The reversible photoisomerization and pH-dependent protonation enable tunable nanoparticle assembly.
• These findings highlight the potential of these stimuli-responsive nanoparticles for controlled release and drug delivery systems.