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"Ghost" silica nanoparticles of "host"-inherited antibacterial action

Halbus, Ahmed F.; Horozov, Tommy S.; Paunov, Vesselin N.


Ahmed F. Halbus


Ahmed F. Halbus


Copyright © 2019 American Chemical Society. We fabricated surface-rough mesoporous silica nanoparticles ("ghost" SiO2NPs) by using composite mesoporous copper oxide nanoparticles ("host" CuONPs) as templates, which allowed us to mimic their surface morphology. The "host" CuONPs used here as templates, however, had a very high antibacterial effect, with or without functionalization. To evaluate the surface roughness effect on the "ghost" SiO2NPs antibacterial action, we functionalized them with (3-glycidyloxypropyl)trimethoxysilane (GLYMO) to permit additional covalent coupling of 4-hydroxyphenylboronic acid (4-HPBA). The diol groups on the bacterial membrane can form reversible covalent bonds with boronic acid (BA) groups on the "ghost" SiO2NPs surface and bind to the bacteria, resulting in a very strong amplification of their antibacterial activity, which does not depend on electrostatic adhesion. The BA-functionalized "ghost" SiO2NPs showed a very significant antibacterial effect as compared to smooth SiO2NPs of the same surface coating and particle size. We attribute this to the "ghost" SiO2NPs mesoporous surface morphology, which mimics to a certain extent those of the original mesoporous CuONPs used as templates for their preparation. We envisage that the "ghost" SiO2NPs effectively acquire some of the antibacterial properties from the "host" CuONPs, with the same functionality, despite being completely free of copper. The antibacterial effect of the functionalized "ghost" SiO2NPs/GLYMO/4-HPBA on Rhodococcus rhodochrous (R. rhodochrous) and Escherichia coli (E. coli) is much higher than that of the nonfunctionalized "ghost" SiO2NPs or the "ghost" SiO2NPs/GLYMO. The results indicate that the combination of rough surface morphology and strong adhesion of the particle surface to the bacteria can make even benign material such as silica act as a strong antimicrobial agent. Additionally, our BA-functionalized nanoparticles ("ghost" SiO2NPs/GLYMO/4-HPBA) showed no detectable cytotoxic impact against human keratinocytes at particle concentrations, which are effective against bacteria. ©

Journal Article Type Article
Publication Date Oct 14, 2019
Journal ACS Applied Materials & Interfaces
Print ISSN 1944-8244
Electronic ISSN 1944-8252
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 11
Issue 42
Article Number acsami.9b14403
Pages 38519−38530
Item Discussed antimicrobial resistance, Gram positive bacteria, Gram negative bacteria, nanoparticles, antimicrobial nanotechnologies
APA6 Citation Halbus, A. F., Horozov, T. S., & Paunov, V. N. (2019). "Ghost" silica nanoparticles of "host"-inherited antibacterial action. ACS applied materials & interfaces, 11(42), 38519−38530.
Keywords Copper oxide nanoparticles; Silica nanoparticles; Mesoporous particles; Templating; Surface roughness; Antibacterial nanoparticles; Boronic acid; Bacteria
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