Surface-tethered poly(acrylic acid) brushes as functional thin film for biosensor application

PMSE 543

Voravee P. Hoven, vipavee.p@chula.ac.th, Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand and Piyaporn Akkahat, akkahat_p@yahoo.com, Program in Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
Carboxyl groups along the surface-tethered poly(acrylic acid) (PAA) brushes serve as precursor moieties for covalent immobilization of bioactive species that act as sensing probes of biosensor. In this research, linear and branched poly(tert-butyl acrylate) (Pt-BA) brushes were prepared by surface-initiated atom transfer radical polymerization of tert-butyl acrylate (t-BA) and self-condensing vinyl copolymerization of t-BA with 2-(2-bromopropionyloxy)ethyl acrylate (BPEA), respectively. Linear and branched PAA brushes were subsequently obtained after tert-butyl groups of Pt-BA brushes were removed by acid hydrolysis. The carboxyl group density of linear and branched PAA brushes can be varied as a function of chain length and comonomer ratio, respectively. The success of biotin attachment to the carboxyl groups of both linear and branched PAA brushes was verified by FT-IR analysis. The binding efficiency of biotin-attached PAA brushes to streptavidin was compared with a conventional precursor layer, SAMs of carboxyl-terminated alkanethiol using SPR spectroscopy.