The article offers information on the concept of synthesized small interfering RNA (siRNA) and its design. siRNA or vector-encoded short hairpin RNA (shRNA) acts as the RNA interference (RNAi) trigger and gets incorporated into a multi-protein complex known as an RNA-induced silencing complex (RISC) when they arrive in the cell. Modifying the phosphorylation status of the ends of the two siRNA strands and establishing chemical modification processes can improve siRNA design.