An OEGylated thiol monolayer for the tethering of liposomes and the study of liposome interactions
Artikel i vetenskaplig tidskrift, 2010

The aim of the present work is to develop a protocol for the specific immobilization of liposomes, via tethers, onto functionalized gold surfaces, and in addition to give one example for such a surface architecture All surface functionalization steps are charcerized and controlled First, mixed thiolate self-assembled monolayers (SAMs) prepared from COOH- and OCH3-terminated oligo(ethylene glycol) (OEG) alkane thiols were characterized by polarization modulation reflection absorption infrared spectroscopy (PM-RAIRS) and by X-ray photoemission spectroscopy (XPS). The composition of the mixed SAMs was found to be close to that of the thiol solution. Next, grafting of biotin conjugated with an NH2-terminated OEG spacer (biotin-OEG-NH2) to the COOH groups via conventional amine coupling was optimized with respect to the COOH/OCH3 ratio of the SAM. The grafting of biotin-OEG-NH2 was assessed by monitoring the binding of neutravidin and albumin to the biotinylated surfaces using quartz crystal microbalance with dissipation monitoring (QCM-D), as well as by PM-RAIRS It was shown that a COOH/OCH3 ratio of around 0.3 was sufficient to saturate the SAMs with neutravidin. Finally, tethering of liposomes onto the neutravidin-terminated SAMs. was achieved. As an application example. of a close packed layer of tethered liposomes was exposed to the membrane-penetrating peptide melittin As monitored by QCM-D. the liposomes fused when interacting with the peptide and ruptured into an extended. supported lipid bilayer over the whole surface. In summary, the described surface modification has potential for the development of assays requiring tethered Intact liposomes, or tethered planar bilayers. Such surface architectures are especially important for the study of transmembrane proteins and peptides.

bilayer-lipid membranes

force microscopy

surfaces

microbalance

Melittin

molecular-conformation

quartz-crystal

PM-RAIRS

gold

self-assembled monolayers

QCM-D

Surface characterization

Thiol-OEG SAM

Tethered liposomes

XPS

normal-alkanethiols

surface-plasmon resonance

infrared-spectroscopy

protein adsorption

Författare

Elisabeth Briand

Chalmers, Teknisk fysik, Biologisk fysik

V. Humblot

Universite Pierre et Marie Curie

C. M. Pradier

Universite Pierre et Marie Curie

Bengt Herbert Kasemo

Chalmers, Teknisk fysik, Kemisk fysik

Sofia Svedhem

Chalmers, Teknisk fysik, Biologisk fysik

Talanta

0039-9140 (ISSN)

Vol. 81 1153-1161

Ämneskategorier

Fysik

DOI

10.1016/j.talanta.2010.01.027