Biologically responsive micelles based on polygonatum sibiricum polysaccharide for docetaxel delivery

This study aimed to develop a pH- and redox-responsive copolymer micelle (PSP-ss-SA) for the delivery of docetaxel (DTX), using the natural polygonatum sibiricum polysaccharide (PSP). PSP-ss-SA was synthesized by conjugating PSP and stearic acid (SA) to both ends of cystamine, with its chemical structure characterized by FTIR and ¹H NMR spectroscopy. PSP-ss-SA could self-assemble into micelles in aqueous solution, with a critical micelle concentration (CMC) of 0.0298 mg/mL. The particle sizes of blank and DTX-loaded PSP-ss-SA micelles were 131.0 ± 0.7 nm and 161.2 ± 1.0 nm, respectively. XRD and DSC characterizations confirmed that DTX was encapsulated within the micelles. Furthermore, PSP-ss-SA micelles exhibited rapid disruption under acidic and reductive conditions, enabling rapid DTX release from the micellar core. Hemolysis and cell experiments demonstrated that PSP-ss-SA micelles had extremely low cytotoxicity toward 4T1 and HeLa cells, while significantly enhancing intracellular DTX accumulation in cancer cells. In summary, our findings indicate that PSP-ss-SA micelles hold great potential as a DTX delivery system, which can significantly improve the therapeutic efficacy of DTX.