The most crucial role of granulocyte colony-stimulating factor
(G-CSF) in the body is to increase the strength of immune system. In
recent years, research on the use of nanoparticles in pharmaceuticals
has been considered, most of which have been for drug-loading purposes.
In this study, a novel G-CSF conjugated dendrimer was synthesized and
characterized using different techniques. In vitro cytotoxicity was
assessed on A549 and L929 cells, while abnormal toxicity was studied in
mice. In vitro and in vivo biological activities were assessed in NFS60
cells and rats, respectively. In addition, in vivo distribution, plasma
half-life, and histopathological effect were studied in rat. The
characterization tests confirmed the successful conjugation. There was
no difference between G-CSF cytotoxicity before and after conjugation,
and no difference with the control group. No mice showed abnormal
toxicity. Although in vitro biological activity revealed both conjugated
and free G-CSF promote proliferation cells, biological activity
decreased significantly after conjugation about one-third of the
unconjugated form. Nonetheless, in vivo biological activity of
conjugated G-CSF increased by more than 2.5-fold relative to the
unconjugated form, totally. Fortunately, no histopathologic adverse
effect was observed in vital rat tissues. Also, in vivo distribution of
the conjugate was similar to the native protein with an enhanced
terminal half-life. Our data revealed that G-CSF conjugated dendrimer
could be considered as a candidate to improve the in vivo biological
activity of G-CSF. Moreover, multivalent capability of the dendrimer may
be used for other new potentials of G-CSF in future perspectives.