TIRF microscopy as a screening method for non-specific binding on surfaces.
We report a method for studying nanoparticle-biosensor surface interactions based on total internal reflection fluorescence (TIRF) microscopy. We demonstrate that this simple technique allows for high throughput screening of non-specific adsorption (NSA) of nanoparticles on surfaces of different chemical composition. Binding events between fluorescent nanoparticles and functionalized Zeonor® surfaces are observed in real-time, giving a measure of the attractive or repulsive properties of the surface and the kinetics of the interaction. Three types of coatings have been studied: one containing a polymerized aminosilane network with terminal -NH(2) groups, a second film with a high density of -COOH surface groups and the third with sterically restraining branched poly(ethylene)glycol (PEG) functionality. TIRF microscopy revealed that the NSA of nanoparticles with negative surface charge on such modified coatings decreased in the following order -NH(2)>-branched PEG>-COOH. The surface specificity of the technique also allows discrimination of the degree of NSA of the same surface at different pH.
Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland. christy.charlton@dcu.ie
Christy
C
Charlton
Vladimir
V
Gubala
Ram Prasad
RP
Gandhiraman
Julie
J
Wiechecki
Nam Cao Hoai
NC
Le
Conor
C
Coyle
Stephen
S
Daniels
Brian D
BD
Maccraith
David E
DE
Williams
D005456:Fluorescent Dyes / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D011485:Protein Binding; D013379:Substrate Specificity; D013499:Surface Properties
D005456:Fluorescent Dyes; D011137:Polystyrenes