Enhancing chemotherapeutic efficiency through improved drug delivery would facilitate treatment of chemoresistant cancers, such as recurrent mammary tumors and liver cancer. One way to improve drug delivery is through the use of nanodiamond (ND) therapies, which are both scalable and biocompatible. Here, we examined the efficacy of an ND-conjugated chemotherapeutic in mouse models of liver and mammary cancer. A complex (NDX) of ND and doxorubicin (Dox) overcame drug efflux and significantly increased apoptosis and tumor growth inhibition beyond conventional Dox treatment in both murine liver tumor and mammary carcinoma models. Unmodified Dox treatment represents the clinical standard for most cancer treatment regimens, and NDX had significantly decreased toxicity in vivo compared to standard Dox treatment. Thus, ND-conjugated chemotherapy represents a promising, biocompatible strategy for overcoming chemoresistance and enhancing chemotherapy efficacy and safety.

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Nanodiamonds (NDs) are promising candidates in nanomedicine, demonstrating significant potential as gene/drug delivery platforms for cancer therapy. We have synthesized ND vectors capable of chemotherapeutic loading and delivery with applications towards chemoresistant leukemia. The loading of Daunorubicin (DNR) onto NDs was optimized by adjusting reaction parameters such as acidity and concentration. The resulting conjugate, a novel therapeutic payload for NDs, was characterized extensively for size, surface charge, and loading efficiency. A K562 human myelogenous leukemia cell line, with multidrug resistance conferred by incremental DNR exposure, was used to demonstrate the efficacy enhancement resulting from ND-based delivery. While resistant K562 cells were able to overcome treatment from DNR alone, as compared with non-resistant K562 cells, NDs were able to improve DNR delivery into resistant K562 cells. By overcoming efflux mechanisms present in this resistant leukemia line, ND-enabled therapeutics have demonstrated the potential to improve cancer treatment efficacy, especially towards resistant strains.

Recent reports have revealed that detonation nanodiamonds (NDs) can serve as efficient, biocompatible, and versatile drug delivery platforms. Consequently, further investigations exploring additional therapeutic applications are warranted. Current limitations associated with the non-specific nature of intravenous drugs limit the potential of certain pharmacological agents. One such treatment that could benefit from a stable delivery platform is antibody (Ab) therapy. Determination of Ab adsorption and desorption to a ND surface was subsequently examined using the transforming growth factor β (TGF-β) antibody as a model therapeutic. ND-Ab complexes were found to be stable in water through enzyme-linked immunosorbent assays (ELISAs), UV-vis spectroscopy and TEM, with no Ab released after ten days. Released Abs were detected in extreme pH solutions (3.5), DMEM (+) serum with pH levels ranging from 4 to 10.5, and inorganic saline solutions. Preserved activity of Abs released in DMEM (+) serum was confirmed using an ELISA. These results suggest ND-Ab complexes are synthesized and stabilized in water and are triggered to release active Abs upon exposure to physiological conditions.