A polyacrylamide microbead-integrated chip for the large-scale manufacture of ready-to-use esiRNA

Endoribonuclease-prepared siRNAs (esiRNAs) have the advantages of cost effectiveness and lower off-target effects than chemically synthesized siRNA. However, the current manufacture of esiRNA is a complex process, requiring an expensive instrument and demanding skills to accomplish the transfer, purification, quantification and normalization of liquid samples. These performances significantly hamper the application of esiRNAs on a large-scale level. In this study, we present a polymer microbead-integrated chip capable of the large-scale manufacture of esiRNA in a convenient and robust manner. This chip is able to perform the amplification, transcription and enzymatic digestion of targets on polymer scaffold, thus simplifying the transfer and purification manipulation process. What is also noted, this chip can readily tailor and normalize the amount of esiRNA product by controlling the number of DNA probes and the cycle of the amplification reaction. Thus the esiRNA, also referred to as gel-esiRNA, can be immediately applied to loss-of-function study without any further treatment. The silencing specificity and efficiency of gel-esiRNAs were assessed on transcriptional, translational or cell functional levels. All data of real-time PCR, Western blot assay, or FACS clearly supported that the gel-esiRNA produced specific gene silencing as effectively as the one generated following the conventional approach. We believe that this approach would provide a more robust and cost-effective choice to manufacture esiRNAs, thus promising both more intensive and extensive applications of these heterogeneous RNA strands.