# Organically Functionalized Magnesium Phyllosilicates: Surface Engineering and Antibacterial Performance

## TL;DR

Scientists created new clay-like materials with functional groups on their surfaces and found they can kill bacteria, especially Gram-positive ones.

## Contribution

A new family of organosilicate layered materials was synthesized and tested for antibacterial properties.

## Key findings

- Amino-functionalized SCAs showed higher antibacterial activity than epoxy-functionalized SCAs.
- Gram-positive bacteria were more susceptible to SCA treatment than Gram-negative bacteria.
- Surface functionalization significantly affects antimicrobial performance.

## Abstract

Synthetic clay analogues (SCAs) of a new organosilicate
layered
material family, in contrast to common clays, are produced via an
in situ room-temperature sol–gel route, providing the possibility
for the design and synthesis of diverse, tailor-made functional groups
on the surface and interior of the synthetic clay sheets. In this
work, we introduce organophyllosilicates bearing different functional
end groups, which are synthesized by a magnesium metal salt precursor
and organosilanes such as (3-aminopropyl)­triethoxysilane (APTEOS), N-[3-(trimethoxysilyl)­propyl]­ethylenediamine (EDAPTEOS), N-(3-trimethoxysilylpropyl)­diethylenetriamine (TAPTMOS),
1,4-bis­(triethoxysilyl)­benzene (BTB), tetraethyl orthosilicate (TEOS),
3-glycidoxypropyltrimethoxysilane (GLYMO), and (3-chloropropyl)­trimethoxysilane
(CPTMOS). The surface free energy for various organosynthetic clay
analogues lies in the 29–252 mJ/m2 range. SCA’s
antimicrobial activity was tested against both Gram-negative and Gram-positive
bacteria to evaluate the effect of surface functionalization on the
viability of these microorganisms. The amino-SCAs displayed higher
antibacterial activity compared to epoxy-SCAs, presenting a dose-dependent
effect and a structure-dependent motif. Furthermore, Gram-positive
bacteria were more susceptible to SCA treatment than Gram-negative.