ac301586q_si_001.pdf (1.25 MB)
Integration of On-Chip Isotachophoresis and Functionalized Hydrogels for Enhanced-Sensitivity Nucleic Acid Detection
journal contribution
posted on 2016-02-20, 15:19 authored by Giancarlo Garcia-Schwarz, Juan G. SantiagoWe introduce an on-chip electrokinetic assay to perform
high-sensitivity nucleic acid (NA) detection. This assay integrates
electrokinetic sample focusing using isotachophoresis (ITP) with a
background signal-removal strategy that employs photopatterened, DNA-functionalized
hydrogels. In this multistage assay, ITP first enhances hybridization
kinetics between target NAs and end-labeled complementary reporters.
After enhanced hybridization, migration through a DNA-functionalized
hydrogel region removes excess reporters through affinity interactions.
We demonstrate our assay on microRNAs, an important class of low-abundance
biomarkers. The assay exhibits 4 orders of magnitude dynamic range,
near 1 pM detection limits starting from less than 100 fg of microRNA,
and high selectivity for mature microRNA sequences, all within a 10
min run time. This new microfluidic framework provides a unique quantitative
assay for NA detection.