Dmnpe

NaYF₄:Yb,Tm nanocrystals and monodisperse silica-coated NaYF₄:Yb,Tm (NaYF4:Yb,Tm@silica, UCPs) were synthesized and characterized following the method described by Guo et al. (2010) [7] and Qian et al. (2009) [9] (link). The UCPs were modified using an amino group following the method described by Guo et al. (2011). DMNPE (Invitrogen) was used to cage siRNAs following the manufacturer's protocol, and UCPs/siRNA-DMNPE complexes were made as described previously by Guo et al. (2011) [14] (link). The ratio of UCPs to siRNA was determined by measuring the zeta potential using Nano-ZS ZEN 3600 (Malvern Instruments Ltd, UK) at 25°C. The UV absorption spectrum was gathered using BioMate 3S UV-visible spectrophotometer (Thermo Scientific) at 25°C.