Springer Science and Business Media LLC

A new water-dispersible nanostructure based on magnetite (Fe3O4) and usnic acid (UA) was prepared in a well-shaped spherical form by a precipitation method. Nanoparticles were well individualized and homogeneous in size. The presence of Fe3O4@UA was confirmed by transmission electron microscopy, Fourier transform-infrared spectroscopy, and X-ray diffraction. The UA was entrapped in the magnetic nanoparticles during preparation and the amount of entrapped UA was estimated by thermogravimetric analysis. Fabricated nanostructures were tested on planktonic cells growth (minimal inhibitory concentration assay) and biofilm development on Gram-positive Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis) and Gram-negative Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) reference strains. Concerning the influence of Fe3O4@UA on the planktonic bacterial cells, the functionalized magnetic nanoparticles exhibited a significantly improved antimicrobial activity against E. faecalis and E. coli, as compared with the Fe3O4 control. The UA incorporated into the magnetic nanoparticles exhibited a very significant inhibitory effect on the biofilm formed by the S. aureus and E. faecalis, on a wide range of concentrations, while in case of the Gram-negative microbial strains, the UA-loaded nanoparticles inhibited the E. coli biofilm development, only at high concentrations, while for P. aeruginosa biofilms, no inhibitory effect was observed. The obtained results demonstrate that the new water-dispersible Fe3O4@UA nanosystem, combining the advantages of the intrinsic antimicrobial features of the UA with the higher surface to volume ratio provided by the magnetic nanocarrier dispersible in water, exhibits efficient antimicrobial activity against planktonic and adherent cells, especially on Gram-positive strains.

A hygroscopicity tandem differential mobility analyzer (HTDMA) technique is used to determine size-effect of nanoparticles (NaCl, (NH4)2SO4, KCl, NH4NO3, MgCl2, CaCl2) on their hygroscopic properties (deliquescence relative humidity (DRH) and hygroscopic growth factor (GF)). The HTDMA system uses a combination of two nano DMAs and two regular DMAs to measure particle size change in a wide dynamic particle size range. Particles are subsequently analyzed with a transmission electron microscopy to investigate the potential effect of particle structure or morphology on the hygroscopic properties. We found that structural properties of NaCl and (NH4)2SO4 particles also play an important role in determination of the DRH and GF and are more pronounced at smaller diameters. Data show that the DRH of NaCl nanoparticles increased from ~75% up to ~83% RH at 8 nm and that their GF decreased with decreasing size. The extent to which the GF of NaCl nanoparticles decreased with decreasing size was greater than theoretically predicted with the Kelvin correction. The GF of furnace-generated NaCl nanoparticles that have pores and aggregate shape was found to be smaller than that of atomizer-generated particles that are close to perfectly cubic. For the case of atomizer-generated (NH4)2SO4 nanoparticles, we observed no significant size-effect on their DRH, and the measured GF agreed well with predicted values using the Kelvin correction. For furnace-generated (NH4)2SO4 nanoparticles, a gradual growth at moderate RH without noticeable deliquescence behavior occurred. Their TEM images showed that contrary to atomizer-generated (NH4)2SO4 nanoparticles the furnace-generated (NH4)2SO4 nanoparticles are not perfectly spherical and are often aggregates having pores and holes, which may favor holding residual water even in the dried condition. For atomizer-generated KCl, MgCl2, and CaCl2 nanoparticles, we observed no significant size-effects on their DRH and GF for the mobility size as small as 20 nm.

Photocatalytic activity of CdS nanoparticles in hydrosulfide-ions air oxidation was revealed and thoroughly investigated. HS− photooxidation in the presence of CdS nanoparticles results predominantly in the formation of SO3 2− and SO4 2− ions. Photocatalytic activity of ultrasmall CdS crystallites in HS– photooxidation is much more prononced as compared to bulk CdS crystals due to high surface area of nanoparticles, their negligible light scattering, improved separation of photogenerated charge carriers etc. It was shown that hydrosulfide ions can be oxidized in two ways. The first is HS− oxidation by the CdS valence band holes. This process rate depends on the rate of comparatively slow reaction between molecular oxygen and CdS conduction band electrons. The second reaction route is the chain-radical HS− oxidation induced by photoexcited CdS nanoparticles and propagating in the bulk of a solution. In conditions favourable to chain-radical oxidation of HS−(i.e. at low light intensities and CdS concentration and high oxygen and Na2S concentrations) quantum yields of the photoreaction reach 2.5.

In this study, CuS nanodisks have been synthesized from a tetraaza (N4) macrocyclic complex precursor by a facile wet chemical method. The crystallinity and morphology of the as-synthesized products were characterized by X-ray diffraction and transmission electron microscopy, which confirm a phase pure crystalline CuS nanostructures with ~15 to 20 nm in dimension with ~5 nm thickness. A possible formation mechanism and growth process of the CuS nanodisks are discussed using thiourea and tetraaza ligand as the sulfur donor and stabilizing agent, respectively. Cyclic N4 ligand also acts as a binding agent to template-guide the oriented growth of CuS nanodisks. The optimized geometry of ligands and complexes was calculated using B3YLP functional, which indicates that the HOMO in the complex located on metal center and N atoms are weakly bonded to the metal center. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than under dark in the presence of H2O2. The C t/C 0 plot as a function of time displays the higher MB degradation activity of CuS nanoparticles with H2O2. The recycle stability of CuS nanoparticles was even found to be >80 % after five cycles studied by repeating the MB degradation with same CuS nanoparticles sample. CuS nanostructures synthesized from a tetraaza macrocyclic complex precursor show the disk-like registry with average lateral dimension between 15 and 20 nm and thickness of 5 nm. The catalytic activity of CuS nanodisks toward MB degradation with light displays the higher MB degradation rate than in dark in the presence of H2O2.

This study aims to investigate a potential alternative for MSP1D1 protein to develop a lipid polymer hybrid nanoparticle (LPHN) system of curcumin using poloxamer 407 and its targeted drug delivery to the brain. Design of experiment (DoE) was used to optimize the lipid nanodisc and LPHN delivery system of curcumin by the thin film hydration method. Solid-state characterization of the optimized lipid nanodiscs and LPHNs was performed using DLS, TEM, SEM, PXRD, and DSC. In vitro release, stability study, and in vivo anti-inflammatory and bioavailability studies in mice brains were performed for the optimized LPHN delivery system. DLS and microscopic data showed that the average sizes of the lipid nanodisc and LPHN systems were 125–198 nm and 135–240 nm, respectively. The LPHN delivery system of curcumin exhibited high entrapment efficiency (95.7 ± 2.2%) compared to lipid nanodiscs (91.2 ± 1.7%). In vitro release data showed slow release of lipid nanodiscs and LPHN systems, particularly after 72 h (47.6% and 37.6%, respectively). Stability data indicated that the LPHN delivery system of curcumin was stable after 3 months, while significant growth in size was observed for lipid nanodiscs. PXRD and DSC results showed the partial amorphization of the LPHN system. In vivo anti-inflammatory data suggested that curcumin has anti-inflammatory activity when delivered as an LPHN system. In vivo bioavailability study showed curcumin (6.3 ng/mL) in brain homogenates of mice treated with the LPHN delivery system, suggesting its potential for targeting the brain to treat neurodegenerative diseases.

A new methodology for the accurate determination of the specific absorption rate of ferrofluids with magnetite nanoparticles of average size of about 10 nm subjected to alternative current magnetic fields is proposed. A simple numerical compensation of the heating rates by the cooling rates obtained at similar temperatures is employed. Comparisons of the as-obtained adiabatic heating curves with theoretical evaluations are discussed.

While nanomedicine has an enormous potential to improve the precision of specific therapy, the ability to efficiently deliver these materials to regions of disease in vivo remains limited. In this study, we describe analyses of (AuNPs)-mmi cellular intake via fluorescence microscopy and its effects on H3K4 and H3K9 histone dimethylation. Specifically, we studied the level of H3K4 dimethylation in serving the role of an epigenetic marker of euchromatin, and of H3K9 dimethylation as a marker of transcriptional repression in four different cell lines. We analyzed histone di-methyl-H3K4 and di-methyl-H3K9 using either variable concentrations of nanoparticles or variable time points after cellular uptake. The observed methylation effects decreased consistently with decreasing (AuNPs)-mmi concentrations. Fluorescent microscopy and a binarization algorithm based on a thresholding process with RGB input images demonstrated the continued presence of (AuNPs)-mmi in cells at the lowest concentration used. Furthermore, our results show that the treated cell line used is able to rescue the untreated cell phenotype.

Mitochondrial gene therapy has the potential for curing a variety of diseases that are associated with mitochondrial DNA mutations and/or defects. To achieve this, it will be necessary to deliver therapeutic agents into the mitochondria in diseased cells. A number of mitochondrial drug delivery systems have been reported to date. However, reports of mitochondrial-targeted DNA delivery are limited. To achieve this, the therapeutic agent must be taken up by the cell (1), after which, the multi-processes associated with intracellular trafficking must be sophisticatedly regulated so as to release the agent from the endosome and deliver it to the cytosol (2) and to pass through the mitochondrial membrane (3). We report herein on the mitochondrial delivery of oligo DNA as a model therapeutic using a Dual Function (DF)-MITO-Porter, an innovative nano carrier designed for mitochondrial delivery. The critical structural elements of the DF-MITO-Porter include mitochondria-fusogenic inner envelopes and endosome-fusogenic outer envelopes, modified with octaarginine which greatly assists in cellular uptake. Inside the cell, the carrier passes through the endosomal and mitochondrial membranes via step-wise membrane fusion. When the oligo DNA was packaged in the DF-MITO-Porter, cellular uptake efficiency was strongly enhanced. Intracellular observation using confocal laser scanning microscopy showed that the DF-MITO-Porter was effectively released from endosomes. Moreover, the findings confirmed that the mitochondrial targeting activity of the DF-MITO-Porter was significantly higher than that of a carrier without outer endosome-fusogenic envelopes. These results support the conclusion that mitochondrial-targeted DNA delivery using a DF-MITO-Porter can be achieved when intracellular trafficking is optimally regulated.

Two-dimensional platforms generate considerable interests due to diverse application. We report a “turn-on” fluorescent nanoprobe for prostate-specific antigen (PSA) detection. It is based on cobalt oxyhydroxide nanosheets (CoOOH NSs). Fluorescein amidite (abbreviated as FAM)-labeled aptamer probe (abbreviated as FAM-aptamer) has been adsorbed onto the nanosheets. Energy transfer between substrate and optical species has induced the quenching of FAM-aptamer emission. The strong affinity of FAM-aptamer to the target PSA causes the formation of a rigid aptamer structure. The integration between FAM-aptamer and CoOOH NSs has been drastically affected. The release of the aptamer probe from the nanosheet surface has been realized. The green luminescence has been recovered. The dynamic nanosensor exhibits highly sensitive performance toward PSA with a linear detection range from 0.1 to 5 ng/mL. Its detection limit is measured to be 56.1 pg/mL. Therefore, a simple and efficient sensing platform for the detection of prostate cancer can be established.