A. P. Puzyr

Nonlinear scattering of light in nanodiamond hydrosol

The nonlinear scattering of light under the conditions of optical limiting of nanosecond pulsed laser radiation at a wavelength of 1064 nm in a nanodiamond (ND) hydrosol has been experimentally studied. Superstable hydrosols were obtained from detonation NDs with a modified surface. Using an improved scheme of z scanning, it is shown that a decrease in the optical transmission coefficient of an ND hydrosol under optical limiting conditions is due to enhanced nonlinear scattering. It is established that the energy of pulsed radiation scattered at a right angle obeys a power law in dependence on the energy density of incident radiation pulses. Hydrosols of detonation NDs with the modified surface exhibit high stability with respect to the periodic laser action at high power density.

Isolation of luminescence system from the luminescent fungus Neonothopanus nambi

56 This study is devoted to the problem of isolation of the lighttemitting system able to luminesce in vitro from the fungus Neonothopanus nimbi. The study was performed with the mycelium of the luminous higher fungus N. nambi, inhabiting the tropp ical forests of South Vietnam. [1] The fungus culture was kindly provided for experiments by Vietnamese researcher Dao Thi Van (private collection of strains To obtain fungal biomass, the mycelium was cultured in Petri plates in a liquid nutrient medium by the techh nology described earlier [2]. The grown mycelium was taken from the Petri dish and washed with deionized (DI) water (MilliiQ system, Millipore, United States) to remove the residual components of the nutrient medium and exometaboliltes. After washing, the remaining water was removed from the mycelial biom ass with filter paper. The isolation of the luminescent system of N. nambi mycelium included the following steps, which were carried out at 0–4°C. Mycelium washed with DI water was ground in the cold with scissors and transferred to a beaker placed in an ice bath. The bioo mass was poured with cold 0.1 M phosphate buffer (pH 7.0) supplemented with 0.1–1.0% BSA (Serva, Germany) in the ratio 1 : 5 (wet biomass weight : buffer volume). The biomass was destroyed with a Volna ultrasonic disintegrator (Russia). Sonication was perr formed at a power of 200 W three times for 5 s at 11min intervals. The homogenate was transferred into chilled tubes and centrifuged at 48 000 g for 30–60 min in an Avanti ® JE centrifuge (BeckmannCoulter, United States). The pellet was discarded, and the supernatant was either used immediately for study (in this case, it was stored at 4°C) or immediately frozen at –20°C and stored at this temperature. The luminescence of the supernatants was meaa sured using a BLM 8801 luminometer (Nauka Special Engineering and Design Department, Krasnoyarsk, Russia) calibrated using the Hastings–Weber radioacc tive standard [3] (one luminescent unit was 10 8 phoo tons per 1 s). The signals were recorded using an LKB 2210 recorder (LKB, Sweden). It was found that supernatants isolated from the mycelium of the luminous fungus N. nambi by the method described above emitted long luminescence (Fig. 1). This fact allowed us to conclude that a selff sufficient luminescent system that ensures luminess cence in vitro was isolated from this fungal species. After filtering the supernatant through a membrane with an …

Damaging Effect of Detonation Diamonds on Human White and Red Blood Cells in vitro

In recent years, extensive research in the effects of fine-dispersion particles on biological objects has been performed. However, our survey of the literature revealed no reports describing direct effects of nanoparticles on highly differentiated human or animal cells. These studies are thought to be of crucial importance, because the effects of fine-dispersion particles are studied, e.g., using an injection in blood vessels of laboratory animals [1]. It was also reported [2, 3] that administration of a nanodiamond (ND) suspension per os has a miraculous healing effect in human patients. Based on these reports, it was suggested that NDs could be used as a remedy in oncology, cardiology, dermatology, for treating vascular diseases, etc.

The Effect of the Size Factor of Nanodiamonds in Suspensions on Optical Power Limiting and Nonlinear Laser Light Scattering

The results of experimental studies of optical power limiting (OPL) and nonlinear light scattering (NLS) at a wavelength of 532 nm in suspensions of detonation-synthesis modified nanodiamonds (MNDs) with different grain-size compositions are described. It is found that, at the same nanoparticle concentration, OPL and NLS are more efficient in suspensions with large MNDs. It is shown that MND suspensions can exhibit a stable long-term operation as OPL in a field of laser pulses with a power density of 0.2 GW/cm2 at a repetition frequency of 1 Hz.

Supramolecular structure of nanodiamond particles and obelin built up on a two-dimensional plate.

Nanodiamonds were previously reported to selectively adsorb recombinant apoobelin from the protein extract of the cells of Escherichia coli [4]. Nanodiamond particles were also found to be able to adsorb active photoprotein on their surface. At the same time, obelin retained its capacity to generate light quanta when interacting with calcium ions. The activity of the protein incorporated into the nanodiamond–obelin complex measured immediately after its formation is 40–50% of the activity of the original protein in the solution (Fig. 1). The decrease in the signal intensity due to extinction and scattering of light quanta by nanodiamond particles incorporated in the complex may probably be neglected, because, according to bioluminescence measurements, the number of particles added into the measuring cell was extremely small.

Effects of Modified Detonation Nanodiamonds on the Biochemical Composition of Human Blood

In vitro experiments showed that protein and non-protein components of human blood serum could be absorbed on the surface of modified nanodiamonds obtained by detonation synthesis. The prospects of using nanodiamond as a new absorbent for hemodialysis, plasmapheresis, and laboratory diagnostics are discussed.

Growth and Bioluminescence of Luminous Bacteria under the Action of Aflatoxin B1 before and after Its Treatment with Nanodiamonds

The effect of aflatoxin B1 on growth and luminescence of marine luminous bacteria P. phosphoreum and recombinant E. coli Z905 cells was investigated. The bidirectional effect of aflatoxin B1 on the studied bacterial species was detected—an inhibition of luminescence in P. phosphoreum and its stimulation in E. coli. It was shown that aflatoxin B1 influences the cell luminescence in the freshly grown cultures and bacteria restored after lyophilization. It was detected that the effect of aflatoxin B1 was graded after interaction with the modified nanodiamond (MND) of detonation synthesis. After mycotoxin’s treatment with MND, it does not cause significant changes in bacterial luminescence. The possibilities for the use of P. phosphoreum and E. coli bacteria in the bioluminescent monitoring of aflatoxin B1 and the use of MND for mycotoxin deactivation are discussed.

Saturable absorption in detonation nanodiamond dispersions

Abstract. We report on a saturable absorption in aqueous dispersions of nanodiamonds with femtosecond laser pulse excitation at a wavelength of 795 nm. The open aperture Z-scan experiments reveal that in a wide range of nanodiamond particle sizes and concentrations, a light-induced increase of transmittance occurs. The transmittance increase originates from the saturation of light absorption and is associated with a light absorption at 1.5 eV by graphite and dimer chains (Pandey dimer chains). The obtained key nonlinear parameters of nanodiamond dispersions are compared with those of graphene and carbon nanotubes, which are widely used for the mode-locking.

Saturable absorption in aqueous suspensions of detonation nanodiamonds under irradiation with femtosecond laser pulses

The phenomenon of saturable absorption has been observed in aqueous suspensions of detonation nanodiamonds (DNDs) with 34, 50, and 110 nm sized clusters of nanoparticles under irradiation with 795-nm laser pulses of 120-fs duration. The saturable absorption intensity has been studied as a function of the DND concentration in suspension. At a concentration of 2 wt % of DNDs with 50-nm average cluster size, the saturable absorption intensity amounts to 950 GW/cm2.

Optical limiting in the near-IR range in nanodiamonds dispersed in D2O

We report for the first time, to the best of our knowlegde, on the optical limiting (OL) in stable suspensions of detonation nanodiamonds dispersed in heavy water at optical communication wavelenghts. The nanosecond Z-scan experiments at a wavelength range of 1400–1675 nm revealed that the OL performance decreases with increasing the wavelength.