TY - JOUR

T1 - Boosting Membrane Interactions and Antimicrobial Effects of Photocatalytic Titanium Dioxide Nanoparticles by Peptide Coating

AU - Caselli, Lucrezia

AU - Parra-Ortiz, Elisa

AU - Micciulla, Samantha

AU - Skoda, Maximilian W.A.

AU - Häffner, Sara Malekkhaiat

AU - Nielsen, Emilie Marie

AU - van der Plas, Mariena J.A.

AU - Malmsten, Martin

N1 - Publisher Copyright: © 2024 The Authors. Small published by Wiley-VCH GmbH.

PY - 2024

Y1 - 2024

N2 - Photocatalytic nanoparticles offer antimicrobial effects under illumination due to the formation of reactive oxygen species (ROS), capable of degrading bacterial membranes. ROS may, however, also degrade human cell membranes and trigger toxicity. Since antimicrobial peptides (AMPs) may display excellent selectivity between human cells and bacteria, these may offer opportunities to effectively “target” nanoparticles to bacterial membranes for increased selectivity. Investigating this, photocatalytic TiO2 nanoparticles (NPs) are coated with the AMP LL-37, and ROS generation is found by C11-BODIPY to be essentially unaffected after AMP coating. Furthermore, peptide-coated TiO2 NPs retain their positive ζ-potential also after 1–2 h of UV illumination, showing peptide degradation to be sufficiently limited to allow peptide-mediated targeting. In line with this, quartz crystal microbalance measurements show peptide coating to promote membrane binding of TiO2 NPs, particularly so for bacteria-like anionic and cholesterol-void membranes. As a result, membrane degradation during illumination is strongly promoted for such membranes, but not so for mammalian-like membranes. The mechanisms of these effects are elucidated by neutron reflectometry. Analogously, LL-37 coating promoted membrane rupture by TiO2 NPs for Gram-negative and Gram-positive bacteria, but not for human monocytes. These findings demonstrate that AMP coating may selectively boost the antimicrobial effects of photocatalytic NPs.

AB - Photocatalytic nanoparticles offer antimicrobial effects under illumination due to the formation of reactive oxygen species (ROS), capable of degrading bacterial membranes. ROS may, however, also degrade human cell membranes and trigger toxicity. Since antimicrobial peptides (AMPs) may display excellent selectivity between human cells and bacteria, these may offer opportunities to effectively “target” nanoparticles to bacterial membranes for increased selectivity. Investigating this, photocatalytic TiO2 nanoparticles (NPs) are coated with the AMP LL-37, and ROS generation is found by C11-BODIPY to be essentially unaffected after AMP coating. Furthermore, peptide-coated TiO2 NPs retain their positive ζ-potential also after 1–2 h of UV illumination, showing peptide degradation to be sufficiently limited to allow peptide-mediated targeting. In line with this, quartz crystal microbalance measurements show peptide coating to promote membrane binding of TiO2 NPs, particularly so for bacteria-like anionic and cholesterol-void membranes. As a result, membrane degradation during illumination is strongly promoted for such membranes, but not so for mammalian-like membranes. The mechanisms of these effects are elucidated by neutron reflectometry. Analogously, LL-37 coating promoted membrane rupture by TiO2 NPs for Gram-negative and Gram-positive bacteria, but not for human monocytes. These findings demonstrate that AMP coating may selectively boost the antimicrobial effects of photocatalytic NPs.

KW - Antimicrobial peptides

KW - lipid membranes

KW - lipid oxidation

KW - LL-37

KW - photocatalysis

KW - TiO

U2 - 10.1002/smll.202309496

DO - 10.1002/smll.202309496

M3 - Journal article

C2 - 38402437

AN - SCOPUS:85186268019

JO - Small

JF - Small

SN - 1613-6810

ER -