A Platform Approach to Gene Delivery via Surface Modified Nanodiamonds

The purpose of gene therapy is to introduce foreign genetic material into host cells to either supplement aberrant genes or to endow additional biological functions. To date, however, there has been only modest progress towards this goal, mainly due to the lack of safe, effective and broadly applicable delivery methods. Functional nanodiamonds (NDs) are rapidly emerging as promising platform carriers for next-generation therapeutics due to their innate biocompatibility, scalability, precise particle distribution, high surface area-to-volume ratio, near-spherical aspect ratio, and easily adaptable carbon surface for bioagent attachment. NDs have been functionalized with a range of therapeutics, proteins, antibodies, DNA, polymers, and other assorted biological agents. Furthermore, NDs are stable and dispersible in water, making them a promising and clinically important modality in improving the efficacy of the treatment of diseases and even some cancers at the molecular level. Mitochondrial function (MTT) and luminescent ATP production assays have demonstrated that NDs are not toxic to a wide variety of cell types. In this study, we functionalized NDs with amine groups via either covalent attachment of (3-aminopropyl) trimethoxysilane or surface immobilization of 800 Da low molecular weight polyethyleneimine (LMW PEI800) for plasmid DNA delivery. The latter delivery approach combines complementary characteristics of PEI800 and NDs to create a hybrid material that exhibits the high transfection efficiency of high molecular weight PEI, but without the inherent high cytotoxicity.