Engineering Phaeodactylum tricornutum exosomes to enhance intracellular fucoxanthin delivery

Fucoxanthin (FX), a carotenoid with anti-inflammatory properties, has potential in tumor therapy. Its use in functional foods and nutraceuticals is limited by poor solubility, stability, and bioavailability. This study introduces an FX-targeted delivery system using a modified Phaeodactylum tricornutum (P. tricornutum) exosome. The system, enhanced with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-polyethyleneglycol-2000-triphenylphosphine (DSPE-PEG2K-TPP, TPP), aims to improve FX bioavailability, stability, and targeted transport. Confocal laser scanning microscopy and Fourier transform infrared spectroscopy verified the effective attachment of TPP to the P. tricornutum exosome surface. Fluorescence imaging revealed efficient cellular uptake of the system, with notable targeting efficiency in RAW264.7 macrophages. The delivery system notably enhanced FX uptake in these macrophages, reducing oxidative cell damage and inducing macrophage polarization, compared to free FX.