Reversible Addition−Fragmentation Chain Transfer Polymerization in DNA Biosensing

Abstract

Reversible addition-fragmentation chain transfer polymerization is employed here to allow detector-free visualization of specific DNA sequences for which dynamic polymer growth is used in signal amplification. In particular, surface-initiated polymer growth was regulated by the immobilization of chain transfer agents on the Au surface where DNA hybridization occurred. A linear polymer growth was observed as a function of the reaction time, characteristic of "living" polymer reactions. Significant improvement in assay sensitivity was realized in comparison to the previously reported polymerization-based sensing method by enhancing polymer growth rate and reducing background noises caused by nonspecific adsorption. Direct visualization of fewer than 2,000 copies of a short oligonucleotide sequence was demonstrated in a detector-free fashion.

Polymerization behavior and polymer properties of eosin-mediated surface modification reactions

“…Aqueous monomer formulations are used to form hydrogels for a wide variety of applications including cell encapsulation [5,6], biodetection [10,11,13,14], and electrophoresis [32]. Surface modification of materials by photografted or polymerized hydrogels is also frequently used.…”

“…Surface-mediated polymerization is a capable and valuable method for modifying surface properties for a variety of applications including improved dispersion of nanoparticles [1,2], generation of antifouling coatings [3,4], cell encapsulation [5,6], drug delivery [7], microfluidic device fabrication [8] and biodetection [9–14]. An important parameter in determining the effectiveness of almost any surface graft in these applications is film thickness.…”

“…Alternatively to photopolymerization, surface-mediated polymerizations are also achieved via thermal polymerization [1,19], atom transfer radical polymerization (ATRP) [13,20], reversible addition fragmentation chain transfer (RAFT) polymerization [14,21], and anionic or cationic polymerization [22,23]. Modifying surface densities of these types of initiating species also allows for control of film properties, but patterning of these surfaces is less straightforward than in photopolymerizable systems in which a simple photomask may be employed.…”

A combining signal amplification of atom transfer radical polymerization and redox polymerization for visual biomolecules detection

“…By present, there were mainly two kinds of polymerization principles proposed to realize biomolecular detection through such strategy. One pioneering approach was promoted by He and coworkers who exhibited effective mass growth upon biomolecular recognition using the controlled/living radical polymerization (CRP) reactions . For another, Bowman and Sikes' groups exerted the photopolymerization advantages of convenience and ease‐operation and successfully explored a novel detection method for signal amplification …”

Activators generated electron transfer for atom transfer radical polymerization for immunosensing

“…The frequency response of as-prepared QCM chip for anti-CRP antibody immobilization was 10 times larger than that with the self-assembly immobilization method. He and co-authors used ATRP as a signal amplification method for DNA detection (Lou et al, 2005;He et al, 2008;Lou and He, 2006). The ATRP initiators immobilized on the substrate surface by DNA hybridization triggered polymer growth, which resulted in local accumulation of monomers and altered the optical property of the substrate.…”