# Biodegradable Polyglycerols Combining Antioxidant Activity and Sulfation-Induced Complement Inhibition

## TL;DR

Researchers developed biodegradable polyglycerols with antioxidant and immune-regulating properties for potential therapeutic use.

## Contribution

Introducing biodegradable and antioxidant polyglycerols with sulfation-induced complement inhibition for therapeutic applications.

## Key findings

- GTA and GTA-S showed the highest antioxidant activity among the tested polymers.
- Sulfated derivatives effectively inhibited complement activation comparable to dPGS and heparin.
- All copolymers were cytocompatible and degradable under physiological conditions.

## Abstract

Polyglycerol platforms
are promising for polymer therapeutics
due
to their multifunctionality and biocompatibility. Our aim was to introduce
biodegradability as well as antioxidant properties to the polyglycerol
backbone using cyclic comonomers with thioether and ester functionalities.
Anionic ring-opening copolymerization of glycidol and either 1,4-oxathiepan-7-one
or thiodiglycolic anhydride yielded the hyperbranched structures:
GOTO or GTA, respectively. Characterization confirmed molecular weights
of 10 kDa and the successful incorporation of 10 mol % comonomer while
maintaining water solubility. Sulfated derivatives, GOTO-S and GTA-S,
were obtained with a high degree of sulfation. All copolymers showed
good cytocompatibility as well as degradability under physiological
conditions. Significant antioxidant activity attributed to the thioether
groups of the copolymers was demonstrated via the ABTS radical scavenging
assay. GTA emerged as the strongest radical scavenger among the polymers
tested, likewise, GTA-S outperformed GOTO-S. Notably, the sulfated
derivatives effectively inhibit complement activation with potencies
comparable to dPGS and heparin, demonstrating their potential for
applications in oxidative stress-related inflammation.