Photosensitizer Functionalized Nanodiamonds for Raman Imaging and Photodynamic Therapy of Cancer Cells

One novel nanoplatform with multiple functions including Raman imaging and photodynamic therapy (PDT) capacities was constructed through modifying nanodiamonds (NDs) with photosensitizer chlorin e6 (Ce6). The NDs-Ce6 nanoparticles show enhanced singlet oxygen generation efficiency relative to free Ce6. Cytotoxicity tests indicate that NDs-Ce6 have negligible influence toward HeLa cells vitality under dark condition but enhanced photodynamic ablation upon 660 nm laser irradiation in comparison with free Ce6. In addition, the NDs-Ce6 could be used as Raman imaging probes toward HeLa cells. These results demonstrate that the NDs-Ce6 multifunctional nanoplatform have attractive features using for Raman imaging and PDT. Additionally, a new idea could be provided for designing the multifunctional platform from the work.

Nanodiamond-Based Theranostic Platform for Drug Delivery and Bioimaging

Nanodiamonds (NDs) are promising candidates for biomedical application due to their excellent biocompatibility and innate physicochemical properties. In this Concept article, nanodiamond-based theranostic platforms, which combine both drug delivery features and bioimaging functions, are discussed. The latest developments of therapeutic strategies are introduced and future perspectives for theranostic NDs are addressed.

Nanodiamonds and Their Applications in Cells

Diamonds owe their fame to a unique set of outstanding properties. They combine a high refractive index, hardness, great stability and inertness, and low electrical but high thermal conductivity. Diamond defects have recently attracted a lot of attention. Given this unique list of properties, it is not surprising that diamond nanoparticles are utilized for numerous applications. Due to their hardness, they are routinely used as abrasives. Their small and uniform size qualifies them as attractive carriers for drug delivery. The stable fluorescence of diamond defects allows their use as stable single photon sources or biolabels. The magnetic properties of the defects make them stable spin qubits in quantum information. This property also allows their use as a sensor for temperature, magnetic fields, electric fields, or strain. This Review focuses on applications in cells. Different diamond materials and the special requirements for the respective applications are discussed. Methods to chemically modify the surface of diamonds and the different hurdles one has to overcome when working with cells, such as entering the cells and biocompatibility, are described. Finally, the recent developments and applications in labeling, sensing, drug delivery, theranostics, antibiotics, and tissue engineering are critically discussed.

Cetuximab-conjugated nanodiamonds drug delivery system for enhanced targeting therapy and 3D Raman imaging

In this study, a multicomponent nanodiamonds (NDs)-based targeting drug delivery system, cetuximab-NDs-cisplatin bioconjugate, combining both specific targeting and enhanced therapeutic efficacy capabilities, is developed and characterized. The specific targeting ability of cetuximab-NDs-cisplatin system on human liver hepatocellular carcinoma (HepG2) cells is evaluated through epidermal growth factor receptor (EGFR) blocking experiments, since EGFR is over-expressed on HepG2 cell membrane. Besides, cytotoxic evaluation confirms that cetuximab-NDs-cisplatin system could significantly inhibit the growth of HepG2 cells, and the therapeutic activity of this system is proven to be better than that of both nonspecific NDs-cisplatin conjugate and specific EGF-NDs-cisplatin conjugate. Furthermore, a 3-dimensional (3D) Raman imaging technique is utilized to visualize the targeting efficacy and enhanced internalization of cetuximab-NDs-cisplatin system in HepG2 cells, using the NDs existing in the bioconjugate as Raman probes, based on the characteristic Raman signal of NDs at 1332 cm^-1 . These advantageous properties of cetuximab-NDs-cisplatin system propose a prospective imaging and treatment tool for further diagnostic and therapeutic purposes.