Use of IR-to-visible upconversion fluorescent nanoparticles for tracking of siRNA delivery

Abstract

IR-to-visible upcoversion fluorescent nanoparticles (UCNs) were developed to track in vitro delivery of small interference RNA (siRNA) and meanwhile efficiently transfect siRNA to the cells. NaYF4 upconversion nanoparticles co-doped with Yb/Tm (NaYF4:Yb,Tm) were conjugated with GL3 siRNA through electrostatic attraction at the weight ratio of 8:3. Then, siRNA- conjugated UCNs were incubated with the cultured human breast cancer MCF-7 cells. After 24h-incubation the successful cellular uptake of siRNA was visualized through the emitted blue fluorescence of siRNA- conjugated UCNs under confocal laser scanning microscopy. After 48h-incubation the efficiency of delivered GL3 siRNA in the inhibition of luciferase gene was ~60% that was determined by luciferase assay. This article provided initial insights into the effectiveness and suitability of NaYF4:Yb,Tm upconversion nanoparticles as an easily detectable and self-tracking delivery vector of siRNA.