# Triethoxysilyl-Functionalized Polyethylenimine: Its Spontaneous Cross-Linking and Drug Retention

## TL;DR

A new coating material was developed that can retain antimicrobial and antiviral agents, offering a stable solution for infection control in public and medical settings.

## Contribution

The study introduces a novel cross-linking method for Si-PEI coatings that effectively retain water-soluble antimicrobial and antiviral agents.

## Key findings

- Si-PEI coatings spontaneously cross-linked at room temperature after solvent evaporation.
- The coatings retained copper(II) ions, sulfonamide antibiotics, and didecyldimethylammonium chloride, reducing leaching.
- The coating effectively suppressed viral infectivity in real-world conditions.

## Abstract

Effective antibacterial and antiviral coatings are expected
to
serve as effective infection control measures in medical and public
environments. In this study, we investigated polyethylenimine functionalized
with triethoxysilyl groups (Si-PEI) as a promising platform material
to implement such coatings feasibly. Si-PEI, synthesized in ethanol
in a one-pot reaction, was coated onto the material surface as a diluted
solution and then spontaneously cross-linked after solvent evaporation
at room temperature. The resulting water-resistant coating layer retained
water-soluble antimicrobial components such as copper­(II) ions and
sulfonamide antibiotics within the cross-linked network, thereby moderately
suppressing their leaching due to casual water exposure. Similar retention
was also implemented for the antiviral agent didecyldimethylammonium
chloride, and the coating layer demonstrated effective and stable
suppression of viral infectivity of deposited droplets under realistic
conditions.