Probing the Microenvironments in a Polymer-Wrapped Core-Shell Nanoassembly Using Pyrene Chromophores

Area of Science:

• Polymer Chemistry
• Nanotechnology
• Spectroscopy

Background:

• Lanthanide-doped upconverting nanoparticles (UCNPs) are functional nanomaterials with applications in bioimaging and therapy.
• Amphiphilic polymer shells can encapsulate UCNPs, creating unique nanoenvironments.
• Understanding these environments is crucial for optimizing UCNP-based applications.

Purpose of the Study:

• To investigate the local environments within amphiphilic polymer shells surrounding lanthanide-doped UCNPs.
• To characterize the hydrophobicity and mobility of molecules within these polymer shells.
• To provide insights for the use of these nanoassemblies as nanoreactors or drug delivery vehicles.

Main Methods:

• Steady-state and time-resolved fluorescence spectroscopy.
• Utilized pyrene chromophores as probes for local environments.
• Analyzed emission lifetime measurements to determine polarity and mobility.

Main Results:

• Identified at least two distinct hydrophobic environments within the polymer shell.
• Pyrene molecules were found to be encapsulated in environments with lower polarity than water.
• Observed migration of pyrene chromophores, indicating mobility within the shell.

Conclusions:

• The amphiphilic polymer shell provides both hydrophobicity and mobility for entrapped molecules.
• These findings are valuable for designing chemical reactions within nanoreactors.
• The results support the potential of these nanoassemblies for therapeutic delivery systems.