Multifunctional nanocomplexes (NCs) consisting of
urocanic acid-modified galactosylated trimethyl
chitosan (UA-GT) conjugates as polymeric vectors,
poly(allylamine hydrochloride)-
citraconic anhydride (PAH-
Cit) as charge-reversible crosslinkers, and
vascular endothelial growth factor (
VEGF)
siRNA as therapeutic genes, were rationally designed to simultaneously overcome the extracellular, cellular, and intracellular barriers for
siRNA delivery. The strong physical stability of UA-GT/PAH-
Cit/
siRNA NCs (UA-GT NCs) at pH 7.4 and 6.5 endowed protection from massive dilution, competitive
ions, and ubiquitous nucleases in the blood and tumorous microenvironment. Their internalization into hepato-
carcinoma cells was facilitated through the recognition of
galactose receptors, followed by effective escape from endosomes/lysosomes owing to the strong buffering capacity of
imidazole residues. At the meantime, the endosomal/lysosomal acidity triggered the charge reversal of PAH-
Cit in UA-GT NCs, thus evoking their structural disassembly and subsequently accelerated release of
siRNA in the cytosol. As a result, robust in vivo performance in terms of both gene silencing and
tumor inhibition was achieved by UA-GT NCs at a low
siRNA dose. Moreover, neither histological nor hematological toxicity was detected following repeated
intravenous administration. Therefore, UA-GT NCs potentially served as an efficient and safe candidate in the treatment of
hepatocellular carcinoma through knocking down the overall barriers for
siRNA delivery.