Bilayer-Coating Strategy for Hydrophobic Nanoparticles Providing Colloidal Stability, Functionality, and Surface...

Area of Science:

• Materials Science
• Nanotechnology
• Surface Chemistry

Background:

• Nanoparticle surface chemistry is crucial for biological applications.
• Hydrophobic nanoparticles often lack stability in aqueous environments.
• Existing methods may not adequately protect nanoparticles or allow for easy functionalization.

Purpose of the Study:

• To introduce a bilayer-based surface modification strategy for hydrophobic nanoparticles.
• To achieve excellent colloidal stability and protection in aqueous media.
• To enable facile surface functionalization for biological applications.

Main Methods:

• A bilayer coating was formed on oleate-capped upconversion nanoparticles (UCNPs) using excess oleate.
• Carbodiimide chemistry was employed for surface functionalization.
• The functionalized UCNPs were tested with a photosensitizer and a nitric oxide (NO) probe.

Main Results:

• The bilayer strategy provided excellent colloidal stability in aqueous environments.
• The UCNPs showed protection against water quenching, preserving luminescence.
• Functionalized UCNPs retained their ability to produce singlet oxygen and detect intracellular NO.

Conclusions:

• The bilayer approach offers a simple and fast method to protect and functionalize inorganic nanoparticles.
• This strategy is suitable for surface engineering of nanosized materials for theranostic applications.
• The method ensures nanoparticle integrity and functionality in biological media.