Control of nanodiamond-doxorubicin drug loading and elution through optimized compositions and release environments

Nanodiamonds (NDs) have been extensively explored in biomedical applications due to their favorable properties, such as biocompatibilities and diverse surface electrostatics that allow rapid conjugations with drugs. Enhancing chemotherapeutic efficacy through optimized nanodiamond drug delivery system would further improve the treatment of cancers. In this study, carboxylated nanodiamonds and original nanodiamonds were involved to explore the maximum efficiency in binding and release capability of doxorubicin (DOX). The binding ratio of NDs and DOX, pH values, and release time were optimized. Notably, an NDX synthesized in 2 mL ND, 5 mL DOX, and 0.061 mL NaOH exhibits a ~63.4% (31.7 wt%) binding efficiency, and NDX release profile quantified in acidic environment exhibits ~99.9% release efficiency of DOX. The present work establishes a foundation for future applications in drug delivery system for enhancing chemotherapy efficacy.