# Star Polymers as a Reducing Agent of Silver Salt and a Carrier for Silver Nanoparticles

## TL;DR

Star polymers can create silver nanoparticles that are used in bone cement to prevent infections without harming mechanical strength.

## Contribution

A new method for synthesizing star polymers that reduce silver salt and carry nanoparticles for biomedical use.

## Key findings

- Star polymers successfully reduced silver nitrate to form spherical silver nanoparticles.
- Hybrid nanomaterials incorporated into bone cement showed antibacterial effects against E. coli.
- The modified bone cement maintained acceptable compressive strength and biocompatibility.

## Abstract

Star polymers—macromolecules featuring multiple arms radiating from a central core—offer unique potential for biomedical applications due to their tunable architecture, multifunctionality and ability to incorporate stimuli-responsive and biocompatible components. In this study, functional star polymers with oligo (ethylene glycol) methyl ether methacrylate (OEOMA) arms and 2-(dimethylamino)ethyl methacrylate (DMAEMA) core units were synthesized via atom transfer radical polymerization (ATRP) using the “arm-first” strategy. The star polymers were used as nanoreactors for the in situ reduction of silver nitrate to form silver nanoparticles (AgNPs) without additional reducing agents. UV–Vis spectroscopy confirmed the formation of spherical AgNPs with absorption maxima around 430 nm, and transmission electron microscopy revealed uniform particle morphology. These hybrid nanomaterials (STR-AgNPs) were incorporated into polymethyl methacrylate (PMMA)-based bone cement to impart antibacterial properties. Mechanical testing showed that the compressive strength remained within acceptable limits, while antibacterial assays against E. coli demonstrated a significant inhibition of bacterial growth. These findings suggest that STR-AgNPs serve as promising candidates for infection-resistant bone implants, providing localized antibacterial effects while maintaining mechanical integrity and biocompatibility.