Search

Laser ultrasound enhancement with carbon-based nanomaterials incorporated into phantom tissues is reported. More specifically, impact of nanodiamonds and graphene oxide on the efficiency of photoinduced pressure excitation was investigated. Agarose-based phantom tissues with and without the nanoparticles were compared. The second harmonic of pulsed Nd:Yag laser (532 nm) was chosen for ultrasound generation. Specific acoustic probe was fabricated for laser-induced ultrasound registration. Dependence of the ultrasound amplitude on concentration of the nanoparticles incorporated into the phantom tissues was analyzed in details. The most significant enhancement of the amplitude ensured by graphene oxide was stated. Considering biocompatibility of the both types of carbon-based nanomaterials, they can be potentially used in future as contrast agents for bio-imaging and theranostic applications.

The research and development for biomedical applications are recently focused on multifunctional nanoparticles. To integrate various functionalities, different methods of modifying the particle’s physical properties are developed. Among the considered, nanodiamond (ND) is a promising candidate for the development of multifunctional complex due to its variable features in size, structure, surface chemistry, physical properties, and biocompatibility. In addition to its well-studied structural, surface, electrochemical and photonic properties, strong magnetism of ND can be observed. In the present work, magnetically modified ND is introduced in terms of its bioapplications. Along with the soft ferromagnetism of ND, the increased fluorescence at one- and two-photon excitation is realized. Utilizing the combined magnetic and fluorescence properties of the magnetically modified ND, fluorescence imaging, fluorescence lifetime imaging and manipulation of cells by magnetic field are demonstrated. The perspectives to use the magnetic ND for drug delivery, cells magnetic separation and filtration, in bioengineering to control the cell distribution combined with imaging and treatment are discussed.

Despite their name, nanodiamonds (ND) are comprised of a complex interplay of different carbon phases. The diamond core is surrounded by the shell consisting mostly of disordered sp 3 carbon and graphene-like carbon (GLC). The complex structure makes the characterization of nanodiamonds (ND) a difficult challenge. Recent development of many varieties of NDs for different applications demands quick and reliable characterization of the content of various carbon fragments, as well as the estimation of the diamond core size. In this work, we apply Raman spectroscopy to study the structure of nanodiamonds from different origins, including those produced by detonation (DND), high pressure high temperature synthesis (HPHT), and pulsed laser irradiation (LND). The relative content of GLC, disordered and surface carbon can be easily determined from Raman spectra. In particular, we show how the content of different structure fragments is changed upon de-agglutination, surface oxidation and ion irradiation. We also compare the different ND production methods in terms of the structural uniformity of the nanoparticles. Raman spectroscopy provides unique quantitative tool for ND characterization; we believe that the present data will be useful for understanding the structure of diamond nanoparticles, and will provide the background for obtaining the NDs with desired properties.

The toxicity of nanomaterials raises major concerns because of the impact that nanomaterials may have on health, which remains poorly understood. We need to explore the fate of individual nanoparticles in cells at nano and molecular levels to establish their safety. Conformational changes in secondary protein structures are one of the main indicators of impaired biological function, and hence, the ability to identify these changes at a nanoscale level offers unique insights into the nanotoxicity of materials. Here, we used nanoscale infrared spectroscopy and demonstrated for the first time that nanodiamond-induced alterations in both extra- and intracellular secondary protein structures lead to the formation of antiparallel β-sheet, β-turns, intermolecular β-sheet, and aggregation of proteins. These conformational changes of the protein structure may result in the loss of functionality of proteins and in turn lead to adverse effects.