Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) were used for monitoring of the procedure for cytochrome CYP11A1 monomerization in solution without phospholipids. It was shown that the incubation of 100 μM CYP11A1 with 12% Emulgen 913 in 50 mM KP, pH 7.4, for 10 min at T = 22°C leads to dissociation of hemoprotein aggregates to monomers with the monomerization degree of (82 ± 4)%. Following the monomerization procedure, CYP11A1 remained functionally active. AFM was employed to detect and visualize the isolated proteins as well as complexes formed between the components of the cytochrome CYP11A1-dependent steroid hydroxylase system. Both Ad and AdR were present in solution as monomers. The typical heights of the monomeric AdR, Ad and CYP11A1 images were measured by AFM and were found to correspond to the sizes 1.6 ± 0.2 nm, 1.0 ± 0.2 nm and 1.8 ± 0.2 nm, respectively. The binary Ad/AdR and AdR/CYP11A1mon complexes with the heights 2.2 ± 0.2 nm and 2.8 ± 0.2 nm, respectively, were registered by use of AFM. The Ad/CYP11A1mon complex formation reaction was kinetically characterized based on optical biosensor data. In addition, the ternary AdR/Ad/CYP11A1 complexes with a typical height of 4 ± 1 nm were AFM registered.
Photodynamic therapy is an advanced method of treating cancer and various benign diseases, including infections. It uses light‐activated molecules [photosensitizers (PSs)] to generate reactive oxygen species (
ROS
) when irradiated with light of a specific wavelength. This study examined the photophysical and photosensitizing activity of the PS chlorin e6 incorporated in a delivery system based on plant phospholipids. This new nanoform of chlorin e6 comprised particles with a diameter of 18.4 ± 2.5 nm and zeta potential of −34.6 ± 3.0 mV. Incorporation of chlorin e6 in phospholipid nanoparticles was observed to cause a bathochromic shift of Q‐band absorption maximum by 14 nm without an absorption change in the range of the Soret band. Fluorescence intensity of chlorin e6 embedded in the phospholipid nanoparticles increased 1.7‐fold. Chlorin e6 in phospholipid nanoparticles, when irradiated, was able to generate
ROS
as shown by oxidation of polyunsaturated fatty acids of the phospholipid matrix of the delivery system and reduced
l
‐glutathione.
In vivo
it was demonstrated that the new nanoform of chlorin e6 provides more accumulation of PSs in tumor tissue than its free form. Moreover, its accumulation in the skin was lower and its elimination from the skin almost five times faster than when administered in free form. The observed differences of this new nanoform of chlorin e6 should lead to enhancement of antitumor efficacy and a decrease in phototoxicity.
Quantum dots (QDs) are nanosized semiconductor crystals. They are currently applied in different science fields such as medicine, namely, cancer diagnostics and treatment. QD toxicity is caused by the toxicity of their components. In vivo application of QDs requires their toxicity assessment, so the purpose of this work has been the estimation of acute and chronic toxicity of the QDs at Danio rerio embryos and larvae, QDs being composed of CdSe/CdS/ZnS/S,S-dihydrolipoic acid/polyacrylic acid. We have found no QD acute toxicity during 48 hours of QDs action at the embryo up to the concentration of 185 µM Cd. QDs have been found to be toxic only at 5-7 days of action, it shows that QDs act accumulatively. Beside lethality, we have observed different larval development defects, that is, differently localized edemas, lag of development, tail curvature, and swimming bladder malformation. Our experimental data as well as literature data show that toxicity of the quantum dots at Danio rerio embryos and larvae is primarily caused by toxic action of Cd 2+ ion which arises from partial dissociation of CdSe and CdS molecules.
The ultrafine formulation on the base of plant phosphatidylcholine and antiinflammatory remedy indomethacin with nanoparticles less than 50 nm was obtained. Drug bioavailability after its peroral administration to rats was more than 2 fold higher as compared with free indomethacin. Increased antiinflammatory activity of indomethacin in phospholipids nanoparticles as compared with its free form was shown in two models of inflammation - adjuvant arthritis in rats and conconavalin A induced edema in mice. The increased bioavailability of indomethacin after administration of its phospholipid formulation allows to decrease a dose for achievement of therapeutic effect, that reduces risks of occurrence of collateral displays.
The recent studies in nanotechnology resulted in the development of novel formulations with improved bioavailability. This is especially important for oral administered drugs as the most convenient formulations. The current review deals with the processes occurring at the gastro-intestinal (GI) tract and their influence on the drug form. The increase of bioavailability of the drug may be achieved through designing novel formulations according to the specific drug properties. They include capsules that release pharmaceutical agents at various parts of the GI tract, floating systems that prolong the presence of the drug in the GI tract, dispersed forms with surface-active soluble polymers, micelles that carry poor-soluble drugs inside their non-polar core, agents that facilitate tight junction opening, such as caprate and chitosan, and lipid-based formulations. The own data show the stimulating influence of phospholipid nanoparticles on peroral absorption of drug indomethacin in rats and on passage of transport marker and drugs through Caco-2 cell monolayer in vitro. The review summarizes current understanding of factors that influence the bioavailability of the oral drug forms, currently used models for pharmacokinetic studies, and various approaches to developing novel pharmaceutical forms that increase the bioavailability of the drugs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.