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Influence of Cu6PS5І nanoparticles on the dielectric properties of planarly oriented 6СВ liquid crystal (LC) is studied in the 10–106-Hz frequency range. Introduction of the nanoparticles is shown to result in an increase of the electric conductivity. Contrary to 6СНВТ LC, the conductivity monotonously depends on the nanoparticles’ concentration. The main reason of the much greater influence of Cu6PS5І nanoparticles on the 6СВ conductivity in comparison with 6СНВТ is related to a greater dissociation coefficient of Cu6PS5І in 6СВ than in 6СНВТ. This is confirmed by the fact that the dipole moment of the 6СВ molecules is greater than that of the 6СНВТ molecules. [ABSTRACT FROM AUTHOR]

Within the frequency range 10...106 Hz, the influence of Cu6PS5I nanoparticles on the dielectric properties of planar oriented liquid crystal 6CHBT has been studied. It has been shown that nanoparticles lead to an increase in conductivity, but the conductivity dependence on concentration is non-monotonic function. It has been suggested that the reason of non-monotonic dependence of conductivity of 6CHBT on the concentration of nanoparticles is significant influence of ion adsorption on the nanoparticle surface and increase in the viscosity of liquid crystal when introducing nanoparticles. [ABSTRACT FROM AUTHOR]

Researched within the frequency range 10-1-106 Hz were dielectric properties of pure 6CHBT liquid crystals and 6CHBT ones with the impurity of Fe3O4 nanoparticles that have the mean diameter 5 nm and weight concentration 10-4 %. The study was performed without and under the influence of direct magnetic field with the induction 0.45 and 0.60 T. It has been shown that the magnetic field influences on the parameters of the near-electrode area of liquid crystal. In the case of liquid crystal with magnetic nanoparticles, the parameter changes caused by the magnetic field depend on the induction value. [ABSTRACT FROM AUTHOR]

We aimed to determine effects of aliskiren, a direct renin inhibitor, loaded onto polymeric nanoparticles on the (pro)renin receptor ( Atp6ap2 ), angiotensin II type 1 receptor ( Agtr1 ), and angiotensin-converting enzyme ( ACE ) gene expression in the heart of spontaneously hypertensive rats (SHR). Twelve-week-old male SHRs were divided into an untreated group and groups treated with powdered aliskiren or aliskiren-loaded nanoparticles (25 mg/kg/day). After three weeks, the accumulation of aliskiren, distribution of polymeric nanoparticles, gene expression of Atp6ap2 and Agtr1 receptors and ACE , and protein expression of NADPH oxidase along with the conjugated diene (CD) concentration were analyzed. The accumulation of aliskiren in the heart was higher in the aliskiren-loaded nanoparticle group than in the powdered group. The fluorescent signals of nanoparticles were visible in cardiomyocytes, vessel walls, and erythrocytes. Aliskiren-loaded nanoparticles decreased the gene expression of Atp6ap2 and ACE , while not affecting Agtr1 . Both forms of aliskiren decreased the protein expression of NADPH oxidase, with a more pronounced effect observed in the aliskiren-loaded nanoparticle group. CD concentration was decreased only in the aliskiren-loaded nanoparticle group. We hypothesize that aliskiren-loaded nanoparticle-mediated downregulation of Atp6ap2 and ACE may contribute to a decrease in ROS generation with beneficial effects in the heart. Moreover, polymeric nanoparticles may represent a promising tool for targeted delivery of aliskiren.

Acute respiratory distress syndrome (ARDS) is a life-threatening condition characterized by the rapid onset of lung inflammation Therefore, monitoring the spatial distribution of the drug directly administered to heterogeneously damaged lungs is desirable. In this work, we focus on optimizing the drug N -acetylcysteine (NAC) adsorption on poly-l-lysine-modified magnetic nanoparticles (PLLMNPs) to monitor the drug spatial distribution in the lungs using magnetic resonance imaging (MRI) techniques. The physicochemical characterizations of the samples were conducted in terms of morphology, particle size distributions, surface charge, and magnetic properties followed by the thermogravimetric quantification of NAC coating and cytotoxicity experiments. The sample with the theoretical NAC loading concentration of 0.25 mg/mL was selected as an optimum due to the hydrodynamic nanoparticle size of 154 nm, the surface charge of +32 mV, good stability, and no cytotoxicity. Finally, MRI relaxometry confirmed the suitability of the sample to study the spatial distribution of the drug in vivo using MRI protocols. We showed the prevailing transverse relaxation with high transverse relaxivity values and a high r 2 ( * ) / r 1 ratio, causing visible hypointensity in the final MRI signal. Furthermore, NAC adsorption significantly affects the relaxation properties of PLLMNPs, which can help monitor drug release in vitro/in vivo.

A colloidal solution of magnetic nanoparticles (MNPs) modified with biocompatible positively charged poly-L-lysine (PLL) with an oleate (OL) layer employed as an initial coating was produced as a potential MRI contrast agent. The effect of various PLL/MNPs' mass ratios on the samples' hydrodynamic diameter, zeta potential, and isoelectric point (IEP) was studied by the dynamic light-scattering method. The optimal mass ratio for MNPs' surface coating was 0.5 (sample PLL 0.5 -OL-MNPs). The average hydrodynamic particle size in the sample of PLL 0.5 -OL-MNPs was 124.4 ± 1.4 nm, and in the PLL-unmodified nanoparticles, it was 60.9 ± 0.2 nm, indicating that the OL-MNPs' surface became covered by PLL. Next, the typical characteristics of the superparamagnetic behavior were observed in all samples. In addition, the decrease in saturation magnetizations from 66.9 Am 2 /kg for MNPs to 35.9 and 31.6 Am 2 /kg for sample OL-MNPs and PLL 0.5 -OL-MNPs also confirmed successful PLL adsorption. Moreover, we show that both OL-MNPs and PLL 0.5 -OL-MNPs exhibit excellent MRI relaxivity properties and a very high r 2 ( * ) /r 1 ratio, which is very desirable in biomedical applications with required MRI contrast enhancement. The PLL coating itself appears to be the crucial factor in enhancing the relaxivity of MNPs in MRI relaxometry.

In addition to their LDL-cholesterol-lowering effect, statins have pleiotropic beneficial effects on the cardiovascular system. However, long-term treatment with statins may be associated with serious side effects. With the aim to make statin therapy more effective, we studied the effects of simvastatin- and coenzyme-Q10-loaded polymeric nanoparticles on the lipid profile and nitric oxide (NO)/reactive oxygen species (ROS) balance in the heart and aorta of adult male obese Zucker rats. The rats were divided into an untreated group, a group treated with empty nanoparticles, and groups treated with simvastatin-, coenzyme Q10 (CoQ10)-, or a combination of simvastatin- and CoQ10-loaded nanoparticles (SIMV+CoQ10). After 6 weeks, the lipid profile in the plasma and the concentration of conjugated dienes in the liver were determined. Nitric oxide synthase (NOS) activity, Akt, endothelial NOS (eNOS), phosphorylated eNOS (p-eNOS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and nuclear factor kappaB (NF-kappaB) protein expressions were measured in the heart and aorta. All simvastatin, CoQ10, and SIMV+CoQ10 treatments decreased plasma LDL levels, but only the combined SIMV+CoQ10 treatment increased NOS activity and the expression of Akt, eNOS, and p-eNOS in both the heart and the aorta. Interestingly, NADPH oxidase in the heart and NF-kappaB protein expression in the aorta were decreased by all treatments, including nanoparticles alone. In conclusion, only combined therapy with SIMV- and CoQ10-loaded nanoparticles increased NOS activity and upregulated the Akt-eNOS pathway in obese Zucker rats, which may represent a promising tool for the treatment of cardiometabolic diseases.

Surface modification of magnetic nanoparticles with poly-l-lysine, proline, and tryptophan was used to design potential theranostic agents for the application in cancer diagnosis and radionuclide-hyperthermia therapy. Characterization of bare and functionalized magnetic nanoparticles was performed in detail. The transparency of the examined magnetic nanoparticles was measured in the non-alternating magnetic field for a complete and better understanding of hyperthermia. For the first time amino acid-functionalized magnetic nanoparticles were labeled with theranostic radionuclides 131 I and 177 Lu. The specific absorption rate (SAR) procured for poly-l-lysine functionalized magnetic nanoparticles (SAR values of 99.7 W/g at H 0  = 15.9 kA/m and resonant frequency of 252 kHz) demonstrated their possible application in magnetic hyperthermia. Poly-l-lysine functionalized magnetic nanoparticles labeled with 177 Lu showed the highest radiochemical purity (>99.00 %) and in vitro stability in saline and serum (>98.00 % up to 96 h). The in vivo analysis performed after their intravenous administration in healthy Wistar rats presented good in vivo stability for several days. Encouraging results as well as magnetic and radiochemical properties of 177 Lu-PLL-MNPs (80 °C) justify their further testing toward the potential use as theranostic agents for diagnostic and combined radionuclide-hyperthermia therapeutic applications., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Antibody-modified magnetic nanoparticles were prepared to study their cellular uptake in 3D multicellular spheroidal cell cultures. For this purpose, carbonic anhydrase IX specific monoclonal antibody VII/20 was selected to conjugate on the surface of positively charged glycine coated magnetic nanoparticles in a form of a stable magnetic fluid. In this work, glycine-functionalized magnetic nanoparticles were characterized by different methods. X-ray photoelectron analysis confirmed the binding of glycine to the magnetic nanoparticles, and quantification of the glycine coating on the surface of the magnetic nanoparticles was conducted by thermogravimetric analysis. The optimal weight ratio of glycine to magnetic nanoparticles was determined to be 5 showing good colloid stability due to the high surface charge density of protonated glycine coating shown by the great zeta potential (⁓40 mV). The antibody conjugation to the functionalized magnetic nanoparticles was performed at an antibody to magnetic nanoparticles weight ratio equal to 0.5. Applications of antibody-modified magnetic nanoparticles in cancer therapy rely on their ability to specifically target cancer tissues and enter the tumour intracellular space. Here, we show that antibody coupled nanoparticle internalization was triggered by selective binding to tumour cells expressing hypoxic marker carbonic anhydrase IX. Moreover, our results confirmed specific penetration of conjugated nanoparticles into the tumour cell spheroids., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The efficient entry of nanotechnology-based pharmaceuticals into target cells is highly desired to reach high therapeutic efficiency while minimizing the side effects. Despite intensive research, the impact of the surface coating on the mechanism of nanoparticle uptake is not sufficiently understood yet. Herein, we present a mechanistic study of cellular internalization pathways of two magnetic iron oxide nanoparticles (MNPs) differing in surface chemistry into A549 cells. The MNP uptake was investigated in the presence of different inhibitors of endocytosis and monitored by spectroscopic and imaging techniques. The results revealed that the route of MNP entry into cells strongly depends on the surface chemistry of the MNPs. While serum bovine albumin-coated MNPs entered the cells via clathrin-mediated endocytosis (CME), caveolin-mediated endocytosis (CavME) or lipid rafts were preferentially involved in the internalization of polyethylene glycol-coated MNPs. Our data indicate that surface engineering can contribute to an enhanced delivery efficiency of nanoparticles., (Copyright © 2021, Svitkova et al.)

Dextran-coated magnetic nanoparticles are promising biocompatible agents in various biomedical applications, including hyperthermia and magnetic resonance imaging (MRI). However, the influence of dextran molecular weight on the physical properties of dextran-coated magnetic nanoparticles has not been described sufficiently. We synthesise magnetite nanoparticles with a dextran coating using a co-precipitation method and study their physical properties as a function of dextran molecular weight. Several different methods are used to determine the size distribution of the particles, including microscopy, dynamic light scattering, differential centrifugal sedimentation and magnetic measurements. The size of the dextran-coated particles increases with increasing dextran molecular weight. We find that the molecular weight of dextran has a significant effect on the particle size, efficiency, magnetic properties and specific absorption rate. Magnetic hyperthermia measurements show that heating is faster for dextran-coated particles with higher molecular weight. The different molecular weights of the coating also significantly affected its MRI relaxation properties, especially the transversal relaxivity r 2 . Linear regression analysis reveals a statistically significant dependence of r 2 on the differential centrifugal sedimentation diameter. This allows the targeted preparation of dextran-coated magnetic nanoparticles with the desired MRI properties. These results will aid the development of functionalised magnetic nanoparticles for hyperthermia and MRI applications.

In this study, we analysed the physico-chemical properties of positively charged magnetic fluids consisting of magnetic nanoparticles (MNPs) functionalised by different amino acids (AAs): glycine (Gly), lysine (Lys) and tryptophan (Trp), and the influence of AA-MNP complexes on the MRI relaxivity. We found that the AA coating affects the size of dispersed particles and isoelectric point, as well as the zeta potential of AA-MNPs differently, depending on the AA selected. Moreover, we showed that a change in hydrodynamic diameter results in a change to the relaxivity of AA-MNP complexes. On the one hand, we observed a decrease in the relaxivity values, r 1 and r 2 , with an increase in hydrodynamic diameter (the relaxivity of r 1 and r 2 were comparable with commercially available contrast agents); on the other hand, we observed an increase in r 2 * value with an increase in hydrodynamic size. These findings provide an interesting preliminary look at the impact of AA coating on the relaxivity properties of AA-MNP complexes, with a specific application in molecular contrast imaging originating from magnetic nanoparticles and magnetic resonance techniques.

Aliskiren, a renin inhibitor, has been shown to have cardioprotective and blood pressure (BP) lowering effects. We aimed to determine the effects of nanoparticle-loaded aliskiren on BP, nitric oxide synthase activity (NOS) and structural alterations of the heart and aorta developed due to spontaneous hypertension in rats. Twelve week-old male spontaneously hypertensive rats (SHR) were divided into the untreated group, group treated with powdered or nanoparticle-loaded aliskiren (25 mg/kg/day) and group treated with nanoparticles only for 3 weeks by gavage. BP was measured by tail-cuff plethysmography. NOS activity, eNOS and nNOS protein expressions, and collagen content were determined in both the heart and aorta. Vasoactivity of the mesenteric artery and wall thickness, inner diameter, and cross-sectional area (CSA) of the aorta were analyzed. After 3 weeks, BP was lower in both powdered and nanoparticle-loaded aliskiren groups with a more pronounced effect in the latter case. Only nanoparticle-loaded aliskiren increased the expression of nNOS along with increased NOS activity in the heart (by 30%). Moreover, nanoparticle-loaded aliskiren decreased vasoconstriction of the mesenteric artery and collagen content (by 11%), and CSA (by 25%) in the aorta compared to the powdered aliskiren group. In conclusion, nanoparticle-loaded aliskiren represents a promising drug with antihypertensive and cardioprotective effects.

Nanoparticles have great potential to be used in various biomedical applications, including therapy or diagnosis of amyloid-related diseases. The physical and chemical properties of iron oxide superparamagnetic nanoparticles (MNPs) functionalized with different amino acids (AAs), namely, with lysine (Lys), glycine (Gly), or tryptophan (Trp), have been characterized. The cytotoxicity of nanoparticles and their effect on amyloid fibrillization of lysozymes in vitro was also verified. The AA-MNPs under study are nontoxic to human SHSY5Y neuroblastoma cells. Moreover, the AA-MNPs were able to significantly inhibit lysozyme amyloid fibrillization and destroy amyloid fibrils. Kinetic studies revealed that the presence of AA-MNPs affected lysozyme fibrillization, namely, the lag phase and steady-state phase of the growth curves. The most effective activities were observed for Trp-MNPs, which revealed the importance of aromatic rings in the structure of AAs used as coating agents. The obtained results indicate the possible application of these AA-MNPs in the treatment of amyloid diseases associated with lysozyme or other amyloidogenic proteins., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Amino-modified magnetic nanoparticles were prepared by direct chemisorption of biocompatible d,l-lysine (DLL) on electrostatically stabilized magnetic nanoparticles with the aim to bind specific antibodies (Ab) able to detect cancer cells. The magnetic nanoparticles prepared by coprecipitation were stabilized in an acidic medium. A full optimization study of amino modification performed by UV/Vis spectroscopy and Dynamic Light Scattering measurement (DLS) confirmed an optimal DLL/Fe 3 O 4 weight ratio of 2. The sample was subjected to complex characterizations using different techniques such as UV/Vis, FTIR and X-ray photoelectron spectroscopies (XPS) together with transmission electron microscopy and size/zeta potential measurements. While FTIR spectroscopy, UV/Vis spectroscopy and XPS confirmed the successful amino modification of Fe 3 O 4 nanoparticles, a characterization using a vibrating sample magnetometer (VSM) indicated superparamagnetic behavior in all the prepared samples, suggesting that the coating process did not significantly affect the size and structure of the Fe 3 O 4 nanoparticles. Magnetic nanoparticles with the optimal DLL content were conjugated with the M75 monoclonal antibody specific to carbonic anhydrase IX (CA IX), which is considered one of the best markers of tumor hypoxia and a prognostic indicator of cancer progression. The results demonstrate that all tested cell lines survived and even proliferated in the presence of amino-modified magnetic nanoparticles. Even the tubulin cytoskeletal structure was not disrupted after the exposure of cells to surface-modified magnetic nanoparticles. In contrast, internalization of the antibody-conjugated magnetic nanoparticles led to abrogation of the formation of long and extended microtubules. Finally, the finding supports the view that the M75 antibody conjugated to nanoparticles mediates their specific uptake and intracellular accumulation and that the antibody conjugated magnetic nanoparticles can be potentially used for the selective growth inhibition of CA IX-expressing cells., (Copyright © 2017 Elsevier B.V. All rights reserved.)

An all-fiber magnetic field sensor based on whispering-gallery modes (WGM) in a fiber micro-resonator infiltrated with ferronematic liquid crystal is proposed and experimentally demonstrated. The cylindrical microresonator is formed by a 1 cm-long section of a photonic crystal fiber infiltrated with ferronematic materials. Both ferronematics suspensions are prepared based on the nematic liquid crystal 1-(trans-4-Hexylcyclohexyl)-4-isothiocyanatobenzene (6CHBT) doped with rod-like magnetic particles in the first case and with spherical magnetic particles in the second case. WGMs are excited in the fiber microresonator by evanescent light coupling using a tapered fiber with a micron-size diameter. The Q-factor of the microresonator determined from the experimentaly measured transmission spectrum of the tapered fiber was 1.975 × 10 3 . Under the influence of an applied magnetic field the WGM resonances experience spectral shift towards shorter wavelengths. The experimentally demonstrated sensitivity of the proposed sensor was -39.6 pm/mT and -37.3 pm/mT for samples infiltrated with rod like and spherical like ferromagnetic suspensions respectively for a magnetic field range (0-47) mT. Reducing the diameter of the cylindrical micro-resonator by tapering leads to enhancement of the magnetic field sensitivity up to -61.86 pm/mT and -49.88 pm/mT for samples infiltrated with rod like and spherical like ferromagnetic suspensions respectively for the magnetic field range (0-44.7) mT.

Presence of protein amyloid deposits is associated with pathogenesis of amyloid-related diseases. Insulin amyloid aggregates have been reported in a patient with diabetes undergoing treatment by injection of insulin. We have investigated the interference of insulin amyloid aggregation with two Fe3O4-based magnetic fluids. The magnetic fluids are able to inhibit insulin amyloid fibrillization and promote disassembly of amyloid fibrils. The cytotoxic effect of amyloid fibrils is attenuated in presence of magnetic fluids probably due to reduction of the fibrils. We suggest that present findings propose the potential use of Fe3O4-based magnetic fluids as the therapeutic agents targeting insulin-associating amyloidosis.

Pathogenesis of amyloid-related diseases is associated with the presence of protein amyloid deposits. Insulin amyloids have been reported in a patient with diabetes undergoing treatment by injection of insulin and causes problems in the production and storage of this drug and in pplication of insulin pumps. We have studied the interference of insulin amyloid fibrils with a series of 18 albumin magnetic fluids (MFBSAs) consisting of magnetite nanoparticles modified by different amounts of bovine serum albumin (w/w BSA/Fe₃O₄ from 0.005 up to 15). We have found that MFBSAs are able to destroy amyloid fibrils in vitro. The extent of fibril depolymerization was affected by nanoparticle physical-chemical properties (hydrodynamic diameter, zeta potential and isoelectric point) determined by the BSA amount present in MFBSAs. The most effective were MFBSAs with lower BSA/Fe₃O₄ ratios (from 0.005 to 0.1) characteristic of about 90% depolymerizing activity. For the most active magnetic fluids (ratios 0.01 and 0.02) the DC50 values were determined in the range of low concentrations, indicating their ability to interfere with insulin fibrils at stoichiometric concentrations. We assume that the present findings represent a starting point for the application of the active MFBSAs as therapeutic agents targeting insulin amyloidosis.