title: Introducing surface-tethered poly(acrylic acid) brushes as 3D functional thin film for biosensing applications.
abstract: 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.
authors.affiliation: Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
authors.forename: Piyaporn
authors.initials: P
authors.lastname: Akkahat
authors.forename: Voravee P
authors.initials: VP
authors.lastname: Hoven
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D001710:Biotin / Q000737:chemistry; D019809:Streptavidin / Q000737:chemistry
chemical_list: D000179:Acrylates; C532460:poly(tert-butyl acrylate); D001710:Biotin; D019809:Streptavidin