| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 601299 | Colloids and Surfaces B: Biointerfaces | 2011 | 8 Pages |
Carboxyl groups of surface-tethered poly(acrylic acid) (PAA) brushes should be able to serve as versatile moieties for a wide range of chemical modifications, including an attachment of bioactive species that can act as sensing probes for biosensors. In this research, poly(tert-butyl acrylate) (Pt-BA) brushes were prepared by surface-initiated atom transfer radical polymerization of tert-butyl acrylate. PAA brushes were then obtained after removal of the tert-butyl groups from the Pt-BA brushes by acid hydrolysis. The carboxyl group density of the PAA brushes can be varied as a function of chain length or molecular weight. The reactivity of the carboxyl groups of PAA brushes towards the immobilization of biotin, a frequently used model bioactive probe in biosensing applications, was evaluated. Qualitative determination of streptavidin (SA) binding to the biotin-attached PAA brushes was verified by fluorescence microscopy. The efficiency of the PAA brushes to act as a three dimensional (3D) precursor layer for biosensing applications was further demonstrated using surface plasmon resonance (SPR), where the biotin-attached PAA brushes showed an enhanced signal for the biospecific binding of SA in comparison with a self-assembled monolayer (SAM) of a carboxyl-terminated alkanethiol, used as a model two-dimensional (2D) conventional precursor layer. The PAA brushes showed very low non-specific interactions with two other tested proteins of a similar pI but different sizes. This desirable feature should be highly beneficial for the development of biosensors.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlightsâ–º A correlation between carboxyl group density and the chain length or molecular weight of the poly(acrylic acid) brushes was evaluated. â–º The layer of poly(acrylic acid) brushes exhibited higher biotin density as compared with the self-assembled monolayer of a carboxyl-terminated alkanethiol, and revealed both a specific binding with streptavidin and also prevented adsorption of other non-specific proteins.
