Trifluoro alkyl oligo(ethylene glycol)-terminated alkanethiol self-assembled monolayers : synthesis, characterisation, and protein adsorption properties

Monomolecular films;Self-assembly (Chemistry);Thiols;Proteins--Absorption and adsorption;Biomedical materials

Bonnet, Nelly ; Hähner, Georg ; Hähner, Georg

University:University of St Andrews

Department:Chemistry (School of)

关键词: Monomolecular films;    Self-assembly (Chemistry);    Thiols;    Proteins--Absorption and adsorption;    Biomedical materials;   

Others  :  https://research-repository.st-andrews.ac.uk/bitstream/handle/10023/2127/NellyBonnetPhDThesis.pdf?sequence=3&isAllowed=y

来源: DR-NTU

【 摘 要 】

Self-assembled monolayers have been proven to be well-ordered and to give stableultrathin films. They show a remarkably high diversity with respect to theirfunctionalisation giving rise to many possible applications. This thesis is focused onthe potential use of these molecular thin films in life sciences. The reproduction of amembrane-like environment with these tightly packed and organized unimolecularlayers has led to important breakthroughs in their nanotechnological application asbiomaterials. Their straightforward modification allows the chemical and physicalproperties of biological interfaces to be altered. In particular, Oligo(ethylene glycol)based alkanethiol self-assembled monolayers were intensively studied as biointerfacesfor their ability to resist the non specific adsorption of proteins. The electrostaticrepulsion which originates from these monolayers was seen as one of the possiblefactors causing this protein repulsion. On the other hand proteins adsorb onalkanethiol self-assembled monolayers. This can be partially attributed to an attractivehydrophobic interaction between the biomolecules and the surface.As a result of the understanding of these two driving forces which are relevant fornon-specific protein adsorption/repulsion, novel self-assembling molecules weretailored in an attempt to adjust the adsorption of proteins at the SAM-liquid interface.This was conceivable with these newly designed SAMs since they allow acombination of these forces. We have chosen the ionic strength of the liquidenvironment as the external parameter which could act on the amount of adsorbedproteins because the electrostatic force created by oligo(ethylene glycol) groupsdepends on it.In addition to the synthesis of six new molecules, the preparation and characterisationof the novel self-assembled monolayers are reported in this thesis. The density of themonolayers was estimated by X-ray photoelectron spectroscopy and ellipsometry, andthe wettability properties were studied by measuring the contact angle. The total forceacting on proteins from the SAMs was studied with an atomic force microscope,equipped with a tip mimicking proteins, by measuring force-distance curves. An in-situ technique was investigated in order to study the influence of the variation of thistotal force on the quantity of adsorbed proteins by varying the ionic strength.