Curcumin/nido-carborane complexes incorporated with crown ether/sodium alginate encapsulated drug delivery strategies exhibit pH-responsive release and enhanced in vitro anti-tumor activity

Curcumin has excellent anti-tumor activity, but its instability at physiological pH, low bioavailability and poor targeting limit curcumin to further become an excellent anticancer drug. In this study, two curcumin/nido-carborane fluorescent polymers, curcumin-borane-crown ether coated by sodium alginate (SA-CBC) and curcumin-borane-crown ether (CBC), were prepared, and SA-CBC with better properties to be the most promising anti-tumor drugs. Crown ether/sodium alginate drug delivery strategies can improve the release property of curcumin. Nido-carborane enhances the targeting of curcumin and the inhibiting effect on tumor cells. After testing, the fluorescence lifetime of SA-CBC was 4.72 ns, indicating good fluorescence properties. In vitro drug release results showed that the constructed drug delivery system released curcumin at a controlled rate. The results of transmission electron microscopy and particle size showed that SA-CBC was well encapsulated, with a particle size of less than 200 nm, easy to be absorbed in vivo. Bioactivity studies showed that SA-CBC had a strong affinity and inhibiting effect on tumor cells, and the inhibition rate could reach 84.5 %. In conclusion, this study provides an innovative protocol for the design of curcumin anticancer drugs and lays the foundation for the development of more effective anti-tumor drugs with small side effects.