“Click” Immobilization on Alkylated Silicon Substrates: Model for the Study of Surface Bound Antimicrobial Peptides

Li, Yan, Santos, Catherine, Kumar, Amit, Zhao, Meirong, Lopez, Analette, Qin, Guoting, McDermott, Alison and Cai, Chengzhi (2011) “Click” Immobilization on Alkylated Silicon Substrates: Model for the Study of Surface Bound Antimicrobial Peptides. Chemistry: A European Journal, 17 (9). pp. 2656-2665. ISSN 0947-6539

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Abstract

We describe an effective approach for the covalent immobilization of antimicrobial peptides (AMPs) to bioinert substrates via CuI-catalyzed azide–alkyne cycloaddition (CuAAC). The bioinert substrates were prepared by surface hydrosilylation of oligo(ethylene glycol) (OEG) terminated alkenes on hydrogen-terminated silicon surfaces. To render the OEG monolayers “clickable”, mixed monolayers were prepared using OEG-alkenes with and without a terminal alkyne protected by a trimethylgermanyl (TMG) group. The mixed monolayers were characterized by X-ray photoelectron spectroscopy (XPS), elliposometry and contact angle measurement. The TMG protecting group can be readily removed to yield a free terminal alkyne by catalytic amounts of CuI in an aqueous media. This step can then be combined with the subsequent CuAAC reaction. Thus, the immobilization of an azide modified AMP (N3-IG-25) was achieved in a one-pot deprotection/coupling reaction. Varying the ratio of the two alkenes in the deposition mixture allowed for control over the density of the alkynyl groups in the mixed monolayer, and subsequently the coverage of the AMPs on the monolayer. These samples allowed for study of the dependence of antimicrobial activities on the AMP density. The results show that a relative low coverage of AMPs (∼1.6×1013 molecule per cm2) is sufficient to significantly suppress the viability of Pseudomonas aeruginosa, while the surface presenting the highest density of AMPs (∼2.8×1013 molecule per cm2) is still cyto-compatible. The remarkable antibacterial activity is attributed to the long and flexible linker and the site-specific “click” immobilization, which may facilitate the covalently attached peptides to interact with and disrupt the bacterial membranes.

Item Type:	Article
Uncontrolled Keywords:	antibacterial activity; antimicrobial peptides; click chemistry; hydrosilylation; organic monolayer
Subjects:	C500 Microbiology F100 Chemistry
Department:	Faculties > Health and Life Sciences > Applied Sciences
Depositing User:	Becky Skoyles
Date Deposited:	23 May 2017 14:10
Last Modified:	12 Oct 2019 18:26
URI:	http://nrl.northumbria.ac.uk/id/eprint/30808

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