No abstract

A novel combination of atom transfer radical polymerization (ATRP) and redox polymerization is here used to allow instrument-free visualization of special biomolecules for which dynamic polymer growth is used in signal amplification. In this method, the convenient and mild redox polymerizationassisted amplification with cerium ammonium (IV) nitrate as oxidant at the second stage was achieved by directly using the hydroxyl groups from poly(hydroxyethyl methacrylate) (PHEMA) synthesized via ATRP at the first stage. The brushed polymers poly(hydroxylethyl methacrylate)-branched-poly (acrylamide) (PHEMA-branched-PAM) prepared by successive ATRP and redox polymerization in situ drastically grew up at the detected biomolecules spot to improve the visibility of biomolecule and simplify the detection procedure. With the proposed strategy, the signal amplification of streptavidin (SA) as model detected biomolecule was investigated on two different substrates such as silicon wafer and gold, respectively. As a result, detection limit of SA was demonstrated on the gold substrates where binding of 1.0 ng/mL SA was differentiable from the background using ellipsometry. Moreover, binding of 0.5 nmol/L DNA led to visually distinguishable spots on the gold surface under mild condition. The proposed method exhibited an efficient amplification performance for molecules detection, and paved a new way for visual diagnosis of biomolecules.

Taking advantage of the nanoparticles' large surface area and structural repeating characteristics, polymeric nanoparticles-participating polymerization-based amplification system was designed to enhance the sensitivity of detection.

In this work, a strategy for chemical synthesis of ascorbic acid functionalized polyacrylates (PAAA) was accomplished in a two‐step process, first a reversible addition fragmentation chain‐transfer (RAFT) polymerization on a benzyl‐protected ascorbyl acrylate monomer, followed by a deprotection (debenzylation) reaction. The polymers were characterized by 1H NMR, 13C NMR and gel permeation chromatograph. The polymerization ability of redox pair including PAAA and H2O2 were conducted through the measurement of 2‐hydroxyethyl acrylate (HEA) conversion against time via real‐time FT‐NIR. It was found that PAAA in the presence of H2O2, independent on itself chain length, exhibited much faster polymerization than small molecule ascorbic acid (smAA) as reductant at identical condition. Interestingly, when the concentration of ascorbate repeating unit was over some critical value, the polymerization kinetics of HEA could be tunable by simply adjusting the initial molar ratio of reductant to oxidant and environmental pH. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011