Fatty chain engineering dictates self-assembly behavior of linker-free artesunate nanoassemblies for optimized antitumor efficacy

Emerging evidence has established artesunate (ART) as a potent anticancer candidate, yet its clinical utility remains constrained by rapid clearance and limited bioavailability. To overcome these limitations, we developed fatty chain-driven self-assembling nanoassemblies (NAs) as an innovative therapeutic platform. In contrast to conventional prodrug-based self-assembled nanoassemblies (PBSANs), our ART conjugates (ART-R) activate antitumor effects without requiring responsive modules, substantially streamlining drug design. In this study, we investigated the assembly behavior, stability, and antitumor efficacy of ART-R conjugates with varying side chain lengths: short (ART-C4), medium (ART-C8, ART-C12), and long (ART-C14, ART-C18). To prolong systemic circulation and achieve tumor-selective release, we engineered reduction-responsive sp-ART-R NAs via 2-Distearoyl-sn-glycero-3-phosphoethanolamine-disulfide bond-polyethylene glycol 2000 (DSPE-SS-PEG_2K) modification. Following comprehensive evaluation, sp-ART-C14 NAs with the optimal side chain length were selected, which exhibit the most suitable octanol-water partition coefficient (logP), good assembly capability, stability, cytotoxicity, as well as optimal pharmacokinetic behavior and tumor accumulation ability. In the 4T1 breast tumor model, sp-ART-C14 NAs also demonstrated excellent therapeutic efficacy. This study overcomes the limitations of traditional PBSANs, eliminates dependence on response modules, and provides a new drug delivery solution for ART.