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Although nanodiamonds have long being considered as a potential tool for biomedical research, the practical in vivo application of nanodiamonds remains relatively unexplored. In this paper, we present the first application of in vivo MRI contrast enhancement using only iron embedded magnetic nanodiamonds. MR image enhancement was clearly demonstrated in the rendering of T2-weighted images of mice obtained using an unmodified commercial MRI scanner. The excellent contrast obtained using these nanodiamonds opens the door to the non-invasive in vivo tracking of NDs and image enhancement. In the future, one can apply these magnetic nanodiamonds together with surface modifications to facilitate drug delivery, targeted therapy, localized thermal treatment, and diagnostic imaging., Comment: 19 pages, 6 figures

Ion implantation is used to create nanodiamonds (NDs) with embedded magnetic ions for use in a wide range of biological and medical applications; however, the effectiveness of this process depends heavily on separating magnetic NDs from nonmagnetic ones. In this study, we use secondary ion mass spectrometry to verify the implantation of magnetic ions in NDs and the success of separation. When applied to a series of NDs with embedded iron or manganese ions, the sorting tool used in this study proved highly effective in selecting magnetic NDs. Besides, multienergy ion implantation and precise thickness control of NDs coating on the silicon wafer were suggested to improve this technology.

The novel concept of modifying and enhancing the properties of existing functional micelles through self-complementary interactions has significant potential. In this study, a practical approach to living polymerization of functionalized thermoresponsive monomers enabled the incorporation of self-constituted multiple hydrogen bonded groups into micelles that have potential as supramolecular drug-delivery systems. Phase transitions and morphological studies in aqueous solution showed that the microstructure can be controlled to achieve well-defined vesicle-like micelles with respect to the strength of the hydrogen bond segment. Thus, the resulting micelles have a very low critical micellization concentration and very high loading capacity (16.1%), making the loading process extremely stable and efficient. Incorporation of the anticancer drug doxorubicin (DOX) affected the micellization process in aqueous solution and enabled fine-tuning of drug loading and precise control of drug release rate with excellent sensitivity. Release studies in vitro showed that DOX-loaded micelles exerted dose-dependent cytotoxicity against human liver carcinoma (HepG2) cells at the physiological temperature of 37 °C. In addition, DOX-loaded micelles were efficiently endocytosed by the cancer cells, which may enable the micelles to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. This newly developed material may provide a potential route towards next-generation drug delivery vehicles. Statement of Significance A breakthrough innovation in water-based thermo-responsive polymers has enabled significant progress in developing smart stimuli-responsive nanocarriers by generating novel “supramolecular polymeric micelles” via self-complementary hydrogen-bonding interactions. These newly developed micelles exhibit extremely high micellar stability and drug loading capacity (up to 16%), excellent thermo-responsive behavior and precise control of drug release rate due to hydrogen-bond-induced physical cross-linking. In addition, doxorubicin-loaded micelles were efficiently endocytosed by the cancer cells, which allows them to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. Thus, this work provides a potential route for the development of next generation multifunctional nanocarriers that have improved safety and to increase the therapeutic efficacy of anticancer therapy.