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Polymer-Coated Nanoarchitectonics of Titanium Dioxide Nanoparticles with Enhanced Antimicrobial Activity : Mechanistic Insights into Localized Particle–Membrane Interactions

Alsharif, Nizar B. LU ; Caselli, Lucrezia LU ; Thapper, Anders LU ; Sparr, Emma LU and Malmsten, Martin LU (2026) In ACS Central Science 12(7). p.951-964
Abstract

While surface modifications are widely pursued to improve antimicrobial performance of photocatalytic nanoparticles (NPs), the particle–membrane interactions responsible for these effects remain underexplored. We address this gap by investigating the influence of coating TiO2 NPs with the cationic polymer poly(2-(dimethylamino)ethyl methacrylate) methyl chloride quaternary salt (qPDMAEMA). In contrast to bare TiO2, the coated NPs adsorb extensively to negatively charged bacteria and bacteria-like membranes, boosting membrane permeabilization upon UV illumination due to formation of reactive oxygen species (ROS). The qPDMAEMA coating was demonstrated not to interfere with ROS formation and to withstand UV... (More)

While surface modifications are widely pursued to improve antimicrobial performance of photocatalytic nanoparticles (NPs), the particle–membrane interactions responsible for these effects remain underexplored. We address this gap by investigating the influence of coating TiO2 NPs with the cationic polymer poly(2-(dimethylamino)ethyl methacrylate) methyl chloride quaternary salt (qPDMAEMA). In contrast to bare TiO2, the coated NPs adsorb extensively to negatively charged bacteria and bacteria-like membranes, boosting membrane permeabilization upon UV illumination due to formation of reactive oxygen species (ROS). The qPDMAEMA coating was demonstrated not to interfere with ROS formation and to withstand UV illumination over time-scales sufficient for membrane binding and disruption. Such effects were highly localized near membrane-bound NPs, consistent with the short diffusion lengths of ROS (≈10 nm for hydroxyl radicals) and the formation of oxidative membrane ‘hot-spots’ in the corresponding vicinity of membrane regions where preferential (localized) NP binding occurs. Such preferential localization is demonstrated to occur at poles and nodes of Escherichia coli bacteria. Hypothesizing this to be driven by colocalization with anionic cardiolipin, studies with giant vesicles containing cardiolipin either uniformly distributed or present in segregated domains showed that the polymer-coated TiO2 NPs preferentially bind to cardiolipin-rich regions of the membrane. Together, these results expand on conventional studies of NP interactions with bacteria and bacteria-like membranes and demonstrate that localized interactions must be considered in studies of bacterial membrane interactions of photocatalytic NPs.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
ACS Central Science
volume
12
issue
7
pages
14 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • pmid:42500029
  • scopus:105045355859
ISSN
2374-7943
DOI
10.1021/acscentsci.6c00511
language
English
LU publication?
yes
id
a6ff5d53-5172-4d1c-9644-5aa00a9b8a44
date added to LUP
2026-09-25 13:35:54
date last changed
2026-09-26 03:00:02
@article{a6ff5d53-5172-4d1c-9644-5aa00a9b8a44,
  abstract     = {{<p>While surface modifications are widely pursued to improve antimicrobial performance of photocatalytic nanoparticles (NPs), the particle–membrane interactions responsible for these effects remain underexplored. We address this gap by investigating the influence of coating TiO<sub>2</sub> NPs with the cationic polymer poly(2-(dimethylamino)ethyl methacrylate) methyl chloride quaternary salt (qPDMAEMA). In contrast to bare TiO<sub>2</sub>, the coated NPs adsorb extensively to negatively charged bacteria and bacteria-like membranes, boosting membrane permeabilization upon UV illumination due to formation of reactive oxygen species (ROS). The qPDMAEMA coating was demonstrated not to interfere with ROS formation and to withstand UV illumination over time-scales sufficient for membrane binding and disruption. Such effects were highly localized near membrane-bound NPs, consistent with the short diffusion lengths of ROS (≈10 nm for hydroxyl radicals) and the formation of oxidative membrane ‘hot-spots’ in the corresponding vicinity of membrane regions where preferential (localized) NP binding occurs. Such preferential localization is demonstrated to occur at poles and nodes of Escherichia coli bacteria. Hypothesizing this to be driven by colocalization with anionic cardiolipin, studies with giant vesicles containing cardiolipin either uniformly distributed or present in segregated domains showed that the polymer-coated TiO<sub>2</sub> NPs preferentially bind to cardiolipin-rich regions of the membrane. Together, these results expand on conventional studies of NP interactions with bacteria and bacteria-like membranes and demonstrate that localized interactions must be considered in studies of bacterial membrane interactions of photocatalytic NPs.</p>}},
  author       = {{Alsharif, Nizar B. and Caselli, Lucrezia and Thapper, Anders and Sparr, Emma and Malmsten, Martin}},
  issn         = {{2374-7943}},
  language     = {{eng}},
  number       = {{7}},
  pages        = {{951--964}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{ACS Central Science}},
  title        = {{Polymer-Coated Nanoarchitectonics of Titanium Dioxide Nanoparticles with Enhanced Antimicrobial Activity : Mechanistic Insights into Localized Particle–Membrane Interactions}},
  url          = {{http://dx.doi.org/10.1021/acscentsci.6c00511}},
  doi          = {{10.1021/acscentsci.6c00511}},
  volume       = {{12}},
  year         = {{2026}},
}