Multifunctional semiconducting polymer dots as a miRNA delivery system for osteogenic differentiation and stem cell tracking

Small interfering RNAs (siRNA) and microRNAs (miRNA) are potent gene regulators through RNA interference (RNAi). In this study, we developed a multifunctional theranostic carrier for small RNA delivery and cell tracking using a polymer based nanoparticle composed of the lipid-like material S14, Pluronic F127 and semiconducting polymer MEH-PPV (SPM-dots). The resulting SPM-dots showed efficient siRNA transfection and labeling of human mesenchymal stem cells (hMSCs). Delivery of miR-29b to hMSCs significantly enhanced osteogenic differentiation. Furthermore, hMSCs transfected with SPM-dots displayed strong fluorescent signals in vivo after subcutaneous transplantation. These findings indicate that SPM-dots hold great potential as carrier for gene delivery and cell tracking applications.