(565c) Comprehensive Micro RNA Profiling By Nanoparticle Electrophoresis in a Gel-Membrane Medium

Irregular expression of about 100 regulatory microRNAs (22 nucleotides) has been identified as viable disease biomarkers. Each disease requires quantification of a subset of these miRNA, with overlapping subsets for different diseases.  With current rtPCR techniques, miRNA profiling for single or multiple diseases needs to be done with multiple samples whose cross-correlations are established with a common reference miRNA that is not irregularly expressed.   Such multi-sample cross-correlation assays require exhaustive analysis with large compounded errors and have hence prevented miRNA profiling as a viable comprehensive screening test for multiple diseases.  We report a novel nanoparticle gel electrophoresis technique that can potentially allow rapid quantification of 100 miRNAs from a single sample. A microfluidic platform for hybrid nanoparticle-gel electrophoresis isolates the miRNA population from the genome of a single lysed cell sample and interrogates them for multiple miRNA targets with minimum analyte loss. A high-field gel electrophoresis technique segregates short miRNAs from longer nucleic acids extracted on-chip from lysed cells or exosomes [1]. The isolated miRNA are then mixed on-chip with a family of nanoparticles of different size and fluorescent/Raman/plasmonic labels followed by preconcentration using an ion-exchange membrane. Dimer particles linked by the target have a lower electrophoretic mobility than the unlinked single particle, thus creating a new band whose intensity allows us to quantify the number of targets. Different particle labels and sizes then allows quantification of a large library of miRNA from a high-density nanoparticle ladder enabled by several new nanoparticle gel electrophoresis techniques.

[1] Taller, D., Richards K., Slouka, S., Senapati, S., Hill, R., Go, D. B. and Chang, H.-C., “On-Chip Surface Acoustic Wave Lysis and ion-exchange membrane detection of exosomal RNA for pancreatic cancer study and diagnosis”, LabChip , 15, 1656-1666 (2015).