Drug-loaded nanoparticles utilizing amphiphilic molecules as nanocarriers were developed broadly for nanoscale drug delivery system. Linear amphiphilic molecule (PEG45C18) based on PEG and alkyl chain was designed and synthesized. To study the influence of alkyl chain on antitumor activity, 10-hydroxycamptothecin (HCPT) was selected as the hydrophobic drug, amphiphilic molecule (PEG45C18) and hydrophilic PEG (PEG45) were applied as nanocarriers to form HCPT-loaded nanoparticles (HCPT/PEG45C18 NPs and HCPT/PEG45 NPs). These two nanoparticles presented high drug-loading content, stability, but different release manner and antitumor efficacy. The HCPT/PEG45C18 NPs existed slower release manner but higher antitumor activity than HCPT/PEG45 NPs, IC50 value was decreased approximately 8.5-fold against 4T1 cells in vitro. Moreover, the antitumor efficacy of HCPT/PEG45C18 NPs on 4T1-bearing mice was promoted significantly, the inhibition rate based on average tumor weight was 1.5-fold higher than HCPT/PEG45 NPs, besides, HCPT/PEG45C18 NPs exhibited better tumor accumulation than HCPT/PEG45 NPs. These results suggested alkyl chain affect the antitumor activity significantly due to nanoparticles decorated with alkyl chains existing higher endocytosis efficacy to cells. According to the enhanced antitumor efficacy, it was suggested that HCPT/PEG45C18 NPs showed the potential application for cancer therapy in clinic, and alkyl chains should be considered for designing biomaterials.
HCPT nanoparticles exhibited strong different cellular internalization efficiency and antitumor activity, which was influenced by the effect of alkyl chains.