title: DNA-functionalized monolithic hydrogels and gold nanoparticles for colorimetric DNA detection.
abstract: Highly sensitive and selective DNA detection plays a central role in many fields of research, and various assay platforms have been developed. Compared to homogeneous DNA detection, surface-immobilized probes allow washing steps and signal amplification to give higher sensitivity. Previously research was focused on developing glass or gold-based surfaces for DNA immobilization; we herein report hydrogel-immobilized DNA. Specifically, acrydite-modified DNA was covalently functionalized to the polyacrylamide hydrogel during gel formation. There are several advantages of these DNA-functionalized monolithic hydrogels. First, they can be easily handled in a way similar to that in homogeneous assays. Second, they have a low optical background where, in combination with DNA-functionalized gold nanoparticles, even ∼0.1 nM target DNA can be visually detected. By using the attached gold nanoparticles to catalyze the reduction of Ag+, as low as 1 pM target DNA can be detected. The gels can be regenerated by a simple thermal treatment, and the regenerated gels perform similarly to freshly prepared ones. The amount of gold nanoparticles adsorbed through DNA hybridization decreases with increasing gel percentage. Other parameters including the DNA concentration, DNA sequence, ionic strength of the solution, and temperature have also been systematically characterized in this study.
authors.affiliation: Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Ajfan
authors.initials: A
authors.lastname: Baeissa
authors.forename: Neeshma
authors.initials: N
authors.lastname: Dave
authors.forename: Brendan D
authors.initials: BD
authors.lastname: Smith
authors.forename: Juewen
authors.initials: J
authors.lastname: Liu
mesh_terms: D003124:Colorimetry / Q000295:instrumentation*; D003460:Crystallization / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation*; D020411:Oligonucleotide Array Sequence Analysis / Q000295:instrumentation*; D010316:Particle Size; D017422:Sequence Analysis, DNA / Q000295:instrumentation*
chemical_list: D020100:Hydrogels; D006046:Gold