Arrays are made based on µParaflo microfluidic technology (Atactic Technologies). On the µParaflo microfluidic chip, each detection probe consists of a chemically modified nucleotide coding segment complementary to target microRNA (from miRBase, http://www.mirbase.org/) or other RNA (control or customer defined sequences) and a spacer segment of polyethylene glycol to extend the coding segment away from the substrate. The detection probes are made by in situ synthesis using PGR (photogenerated reagent) chemistry