Nanodiamonds inhibit scratch-wound repair in lung epithelial cell monolayers by blocking cell migration and inhibiting cell proliferation

Carboxyl nanodiamonds inhibit melanoma tumor metastases by blocking cellular motility and invasiveness

Carboxyl nanodiamond (cND) nanoparticles are actively internalized by B16F10 melanoma cells in culture. Treatment of B16F10 tumor cells with cNDs in vitro inhibited their ability to (i) migrate and invade through porous membranes in a transwell culture system, (ii) secrete matrix metalloproteinases (MMPs) MMP-2 and MMP-9, and (iii) express selected epithelial-mesenchymal transition markers critical for cell migration and invasion. Administration of luciferase-transfected B16F10-Luc2 melanoma cells resulted in a rapid growth of the tumor and its metastasis to different organs that could be monitored by in vivo bioluminescence imaging as well as by ex vivo BLI of the mouse organs. After tumor cells were administered intravenously in C57Bl/6 mice, administration of cNDs (50 μg i.v. every alternate day) resulted in marked suppression of the tumor growth and metastasis in different organs of mice. Subcutaneous administration of B16F10 cells resulted in robust growth of the primary tumor subcutaneously as well as its metastasis to the lungs, liver, spleen, and kidneys. Intravenous treatment with cNDs did not affect the growth of the primary tumor mass but essentially blocked the metastasis of the tumor to different organs. Histological examination of mouse organs indicated that the administration of cNDs by itself was safe and did not cause toxic changes in mouse organs. These results indicate that the cND treatment may have an antimetastatic effect on the spread of B16F10 melanoma tumor cells in mice. Further exploration of cNDs as a possible antimetastatic therapeutic agent is suggested.

Safety assessment of new nanodiamonds@corrole hybrids addressed by the response of RAW-264.7 macrophages

Safety assessment of carbon nanomaterials is of paramount importance since they are on the frontline for applications in sensing, bioimaging and drug delivery. The biocompatibility and safety of functionalized nanodiamonds (NDs) are here addressed through the study of the pro-inflammatory response of RAW-264.7 macrophages exposed to new nanodiamonds@corrole hybrids. The corrole unit selected is as a prototype for a hydrophobic organic molecule that can function as a NIR fluorophore reporter, an optical sensor, a photodynamic therapy agent or a photocatalyst. The new functional nanohybrids containing detonated nanodiamonds (NDs) were obtained through esterification using carboxylated NDs and glycol corroles. The success of the covalent functionalization via carbodiimide activation was confirmed through X-ray photoelectron spectroscopy (XPS), Raman and Fourier transform infrared (FTIR) spectroscopy. The UV-vis absorption and emission spectra of the hybrids are additive with respect to the corrole features. The cellular uptake, localization, cell viability and effects on immune cell activation of the new hybrids and of the precursors were carefully investigated using RAW-264.7 macrophages. Overall results showed that the ND@corrole hybrids had no pro-inflammatory effects on the RAW-264.7 macrophage cell line, making them an ideal candidate for a wide range of biomedical applications.

How Nanoparticles Open the Paracellular Route of Biological Barriers: Mechanisms, Applications, and Prospects

Biological barriers are essential physiological protective systems and obstacles to drug delivery. Nanoparticles (NPs) can access the paracellular route of biological barriers, either causing adverse health impacts on humans or producing therapeutic opportunities. This Review introduces the structural and functional influences of NPs on the key components that govern the paracellular route, mainly tight junctions, adherens junctions, and cytoskeletons. Furthermore, we evaluate their interaction mechanisms and address the influencing factors that determine the ability of NPs to open the paracellular route, which provides a better knowledge of how NPs can open the paracellular route in a safer and more controllable way. Finally, we summarize limitations in the research models and methodologies of the existing research in the field and provide future research direction. This Review demonstrates the in-depth causes for the reversible opening or destruction of the integrity of barriers generated by NPs; more importantly, it contributes insights into the design of NP-based medications to boost paracellular drug delivery efficiency.