Primer3 is a very powerful PCR primer design online application permitting one considerable control over the nature of the primers, including size of product desired, primer size and Tm range, and presence/absence of a 3’-GC clamp. Registration not required.
TargetScan (Whitehead Institute) predicts biological targets of miRNAs by searching for the presence of conserved 8mer and 7mer sites that match the seed region of each miRNA Registration not required.