45 research outputs found
Enabling in vivo measurements of nanoparticle concentrations with three-dimensional optoacoustic tomography
In this report, we demonstrate the feasibility of using optoacoustic tomography (OAT) to evaluate biodistributions of nanoparticles in animal models. The redistribution of single-walled carbon nanotubes (SWCNTs) was visualized in living mice. Nanoparticle concentrations in harvested organs were measured spectroscopically using the intrinsic optical absorption and fluorescence of SWCNTs. Observed increases in optoacoustic signal brightness in tissues were compared with increases in optical absorption coefficients caused by SWCNT accumulation. The methodology presented in this report can further be extended to calibrate the sensitivity of an optoacoustic imaging system for a range of changes in optical absorption coefficient values at specific locations or organs in a mouse body to enable noninvasive measurements of nanoparticle concentrations in vivo. Additionally, qualitative information provided by OAT and quantitative information obtained ex vivo may provide valuable feedback for advancing methods of quantitative analysis with OAT
Optical clearing of skin enhanced with hyaluronic acid for increased contrast of optoacoustic imaging
Tribotechnical characteristics of carbon-bearing lubricants
The development of technology for manufacturing nanostructured substances in amounts that could suffice an interlaboratory research is a high priority task for the implementation of nanoproducts. The ultra dispersiblis clusters of synthetic carbon are used as on extra component in polymeric materials. The substances have a high dispersibility and activity of the surface. To study properties of mineral oils, modified ultra dispersiblis clusters of synthetic carbon is of interest. The present activity is devoted to the research of the modifying influence of ultra dispersiblis clusters of synthetic carbon on viscosity of the characteristic of mineral oils and their stability at various temperatures. In the preparation of diamond secondary suspensions not only statistic average sizes of particles should be taken into consideration, but also polydispersity parameters of nanodiamond particle population too
Temperature-dependent optoacoustic response and transient through zero Grüneisen parameter in optically contrasted media
Non-invasive optoacoustic mapping of temperature in tissues with low blood content can be enabled by administering external contrast agents. Some important clinical applications of such approach include temperature mapping during thermal therapies in a prostate or a mammary gland. However, the technique would require a calibration that establishes functional relationship between the measured normalized optoacoustic response and local tissue temperature. In this work, we investigate how a key calibration parameter – the temperature of zero optoacoustic response (T0) – behaves in different environments simulating biological tissues augmented with either dissolved or particulate (nanoparticles) contrast agents. The observed behavior of T0 in ionic and molecular solutions suggests that in-vivo temperature mapping is feasible for contrast agents of this type, but requires knowledge of local concentrations. Oppositely, particulate contrast agents (plasmonic or carbon nanoparticles) demonstrated concentration-independent thermal behavior of optoacoustic response with T0 defined by the thermoelastic properties of the local environment
Dimensional boundary between the nano- and volume status
There is measured border between nano- and macrostate of substance. This fact is explained with
the Debye model for the distribution of the frequencies of phonons in crystals. If the size of crystal such that
a phonon with a wave-length bigger than the Debye’s wave-length can not propagate, it acquires the
properties of a substance different from the macroscopic properties of the crystal
Transparent dielectrics structure nontermal changes after laser treating
Changes in the molecular structure of polymethyl methacrylate caused by irradiation with laser pulses of different powers were investigated by x-ray diffractometry methods. An analysis was made of the position and half-width of a halo in x-ray diffractograms. Coherent scattering regions and the distributions of the moduli of the interatomic vectors were determined. Action of laser radiation on this transparent dielectric induced molecular structure changes associated with an increase in the molecular order in the amorphous matrix and with the formation of clusters at certain specific laser radiation energies. Similar effects can be observed in glasses
Laser nanothermolysis of human leukemia cells using functionalized plasmonic nanoparticles
In the present work, we present the use of gold nanorods as plasmonic nanoparticles for selective photothermal therapy of human acute (HL-60) and chronicle (K-562) leukemia cells using a near-infrared laser. We improved a published methodology of gold nanorods conjugation to generate high yields of narrow band gold nanorods with an optical absorption centered at 760 nm. The manufactured nanorods were pegylated and conjugated with monoclonal antibody to become non-toxic as biocompatible nanothermolysis agent. Gold nanorods are synthesized and conjugated to CD33 monoclonal antibody. After pegylation, or conjugation with CD33 antibody, gold nanorods were non-toxic to acute and chronic leukemia cells. Our modified gold nanorods CD33 conjugates shown high level of accumulation for both leukemia cell lines, and successful used for nanothermolysis of human leukemia cells in vitro. Each sample was illuminated with 1 or 3 laser shots as for low and for high laser fluence. The radiation was provided by a Quanta Systems q-switched titanium sapphire laser, and the system was designed for maximum sample coverage using non-focused illumination. HL-60 and K-562 cells were treated for 45 min with gold nanorods CD33 conjugated, or with pegylated gold nanorods. The effect of pulsed-laser nanothermolysis for acute and chronic leukemia cells were investigated with cell counting for number of living cells, percentage of cell death and functional parameters such as damage of cell membrane and metabolic activity. Gold nanorods CD33 conjugates significantly increase cell damage for low fluence laser and completely destroyed cancer cells after 3 pulses for low fluence (acute leukemia) and for high fluence laser as for HL-60 (acute) and for K-562 (chronicle) leukemia cells