Thiol-containing hyperbranched polysiloxane for scavenging reactive oxygen species

Area of Science:

• Polymer Chemistry
• Biomaterials Science
• Photophysics

Background:

• Unconventional luminescent polymers are valuable in biology due to fluorescence and biocompatibility.
• The luminescent properties and reactive oxygen species (ROS) scavenging mechanisms of thiol-containing polymers require further investigation.

Purpose of the Study:

• To synthesize and characterize novel hyperbranched polysiloxanes with terminal thiol groups.
• To explore the relationship between polymer structure, luminescence, and ROS scavenging capabilities.
• To elucidate the mechanism behind the enhanced fluorescence properties.

Main Methods:

• Polycondensation reaction to synthesize three hyperbranched polysiloxanes (HE, HP, HB) with varying thiol group chain lengths.
• Spectroscopic analysis (fluorescence emission) and quantum yield determination.
• Density Functional Theory (DFT) calculations to investigate structural properties and interactions.
• Biocompatibility and ROS scavenging assays.

Main Results:

• HP demonstrated longer-wavelength emission (480 nm) and a higher quantum yield (12.23%) compared to HE and HB.
• DFT calculations and experimental data indicated that hydrogen bonds and O⋯O interactions enhance conformational rigidity, contributing to HP's superior fluorescence.
• HP exhibited excellent biocompatibility and significant ROS scavenging capacity (up to 35.095%).

Conclusions:

• Structural rigidity, influenced by hydrogen bonds and O⋯O interactions, is critical for superior fluorescence in hyperbranched polysiloxanes.
• HP is a promising fluorescent polymer with excellent biocompatibility and ROS scavenging ability.
• This study offers a novel fluorescent polymer for potential therapeutic applications in ROS-related diseases.