Chlorosulfonation of polystyrene substrates for bioanalytical assays: distribution of activated groups at the surface.
In this work the activation of transparent PS substrates by chlorosulfonation is described and their distribution in the subsurface region is analyzed. For this purpose XPS, FTIR-ATR and colorimetry have been used. It is shown that the electrophilic aromatic substitution of polystyrene in pure chlorosulfonic acid is extremely quick with complete surface coverage by chlorosulfonic groups achieved after only a 10 minute reaction time at -10 °C. It is further demonstrated that the reaction is very surface selective and that even after reaction times as long as 3 hours, the modification is limited to a layer with a thickness of less than one micron. The activated PS substrates can be further functionalized in a second step with carboxylic groups. Due to the excellent optical transparency that the samples maintain upon modification, the modified systems were successfully probed for use in ELISA assays.
Institute of Polymer Science and Technology, ICTP-CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain.
Anselmo
A
del Prado
Nerea
N
Briz
Rodrigo
R
Navarro
Mónica
M
Pérez
Alberto
A
Gallardo
Helmut
H
Reinecke
D003124:Colorimetry; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015850:Interleukin-6 / Q000032:analysis; D056951:Photoelectron Spectroscopy; D011137:Polystyrenes / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013451:Sulfonic Acids / Q000737:chemistry*; D013499:Surface Properties
D015850:Interleukin-6; D011137:Polystyrenes; D013451:Sulfonic Acids; C013880:chlorosulfonic acid