Fig 8 - uploaded by Daniil Chumakov
Content may be subject to copyright.
(Color online) Assessment of glutathione reductase activity in D. salina (a) and HeLa cultures (b) after exposure to cells with PGNP-2.
Similar publications
En los textos mortuorios del antiguo Egipto, el difunto toma la forma de distintas entidades (animales, plantas y otros elementos de la naturaleza, y también dioses) para superar peligros en el más allá. En la fórmula 49 de los Textos de los Ataúdes, adopta la sorprendente forma de una pulga. Hasta la fecha, sólo conocemos copia de esta fórmula en...
Citations
... Cytotoxicity can be low for some analyzed cells and medium for others [42]. AuNP effects on biological tested objects are dependent on the NP shape, size, dispersion medium [43,44]. Different NP can affect different structures and processes in the investigated bio-samples [44]. ...
In the present work, we report the imaging of Au nanostars nanoparticles (AuNSt) and their multifunctional applications in biomedical research and theranostics applications. Their optical and spectroscopic properties are considered for the multimodal imaging purpose. The AuNSt are prepared by the seed-meditated method and characterized for use as an agent for bio-imaging. To demonstrate imaging with AuNSt, penetration and localization in different biological models such as cancer cell culture (A549 lung carcinoma cell), 3D tissue model (multicellular tumor spheroid on the base of human oral squamous carcinoma cell, SAS) and murine skin tissue are studied. AuNSt were visualized using fluorescence lifetime imaging (FLIM) at two-photon excitation with a pulse duration 140 fs, repetition rate 80 MHz and 780 nm wavelength femtosecond laser. Strong emission of AuNSt at two-photon excitation in the near infrared range and fluorescence lifetime less than 0.5 ns were observed. It allows using AuNSt as a fluorescent marker at two-photon fluorescence microscopy and lifetime imaging (FLIM). It was shown that AuNSt can be observed inside a thick sample (tissue and its model). This is the first demonstration using AuNSt as an imaging agent for FLIM at two-photon excitation in biosystems. Increased scattering of near-infrared light upon excitation of AuNSt surface plasmon oscillation was also observed and rendered using a possible contrast agent for optical coherence tomography (OCT). AuNSt detection in a biological system using FLIM is compared with OCT on the model of AuNSt penetrating into animal skin. The AuNSt application for multimodal imaging is discussed.
The present work was aimed at the synthesis, characterization, and cytotoxicity studies of a composition based on liposomes with hydroxyaluminum phthalocyanine (HAPC) and gold nanoparticles (GNP) for combined photodynamic and photothermal therapy. Liposomes were synthesized using HAPC and GNP stabilized with sodium citrate and were obtained from phosphatidylcholine (PC) and cholesterol (CS) by hydration of thin lipid films. Liposomes with diameters of 184 ± 47 nm contained a suspension of HAPC (0.9 mg/mL) and GNP (0.068 mg/mL). Their cytotoxicity on Vero cells and their effect on the activity of a membrane-attacking complex of the complement system were studied. The liposomes exhibited a dose-dependent cytotoxicity that was slightly higher than that of the components and activated the complement system at a concentration corresponding to the IC50 value. However, this effect was not manifested at the expected therapeutic concentration, which indicated the possibility of using them in vivo.
It has been found that the addition of ammonia water to a gold sol obtained by the Duff method induces the growth of the gold particles. The growth kinetics of such particles in alkaline solutions of ammonia and sodium hydroxide has been investigated. Using the modified Kolmogorov–Johnson–Mel–Avrami model, the aggregative mechanism of nanoparticle growth has been revealed for a system with the maximum NH3⋅H2O concentration, while a mixed mechanism, which includes the Ostwald ripening, has been found for other systems. It has been shown that the sizes and dispersity of the final particles can be controlled by varying the concentration of ammonia water and the time of preliminary incubation of an initial sol, while sodium hydroxide does not exhibit such ability. It has been assumed that the decomposition of gold–phosphine complexes, which stabilize the ultrafine particles, followed by the formation of gold–ammonia complexes is the most probable explanation for the action of ammonia water on the Duff sols.
Fluorescent gold nanoclusters (AuNCs) with an average diameter of 2.7 ± 1.0 nm stabilized with 11-mercaptoundecanoic acid were supported on halloysite nanotubes modified with aminosilane. The cytotoxicity of the obtained fluorescent material was investigated in A549 human cells. The AuNCs stabilized on halloysite showed good uptake by the cells. The material did not cause a pronounced toxic effect and visible membrane damage within the 25–50 μg/mL concentration range. An increase in nanocomposite concentration to 100 μg/mL led to massive cell death via apoptosis. This concentration-dependent toxicity mechanism allows for using AuNCs stabilized on halloysite for halloysite visualization in biological objects, bioimaging, and cancer therapy.