Typically, PEG-CTA (4.00 mg), METAC (8.3 mg, 0.04 mmol), PAA (2.9 mg, 0.04 mmol), BAC (2.1 mg, 8.0 × 10−3 mmol), HMP (2-hydroxy-2-methyl-1-propanone, 0.1 mg, 8.00 × 10−4 mmol), and NaCl (3.5 mg, 0.06 mmol) were dissolved in 2-ml water. The pH of the solution was adjusted to 6.5. The tube was sealed and de-oxygenated by three freeze-vacuum-thaw cycles in nitrogen atmosphere. Then, the tube was exposed to UV light for 3 hours. The NPs were separated from the template by centrifugation using 1.5 M NaCl as eluent for three times with an Amicon Ultra centrifugal filter (Millipore; molecular weight cutoff = 100 kDa) followed by dialyzing against water to remove the salt. Alendronate-decorated core-shell polyelectrolyte NPs were synthesized as abovementioned method using alendronate-modified AD-PEG-CTA. The “bare” PMETAC NPs (no PEG shell) were synthesized according to a previous report (27 ).
For conjugation with siRNA, NPs were mixed with siRNA in culture medium/DEPC (diethyl pyrocarbonate) water/sterile saline and incubated for about 3 min. Then, the medium was added into cultured cells.
For conjugation with siRNA, NPs were mixed with siRNA in culture medium/DEPC (diethyl pyrocarbonate) water/sterile saline and incubated for about 3 min. Then, the medium was added into cultured cells.
