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A progressive way in photodynamic therapy is to design photosensitive agents that may operate at lower optical power. Hybrid organic–inorganic silver-, iron-, and silver&iron-contained nanoparticle...

The development of tissue scaffolds able to provide proper and accelerated regeneration of tissue is a main task of tissue engineering. We developed a nanocomposite gel that may be used as an injectable therapeutic scaffold. The nanocomposite gel is based on biocompatible gelling agents with embedded nanoparticles (iron oxide, silver, and hydroxyapatite) providing therapeutic properties. We have investigated the microstructure of the nanocomposite gel exposed to different substrates (porous materials and biological tissue). Here we show that the nanocomposite gel has the ability to self-reassemble mimicking the substrate morphology: exposition on porous mineral substrate caused reassembling of nanocomposite gel into 10× smaller scale structure; exposition to a section of humerus cortical bone decreased the microstructure scale more than twice (to ≤3 μm). The reassembling happens through a transitional layer which exists near the phase separation boundary. Our results impact the knowledge of gels explaining their abundance in biological organisms from the microstructural point of view. The results of our biological experiments showed that the nanocomposite gel may find diverse applications in the biomedical field.

In this work the flower-like hierarchical structures (HS) based on 3D pristine ZnO, ZnO:Eu3+ and ZnO:Eu3+@Au were successfully obtained by a template-free solvothermal and deposition-precipitation method. The decolorization/photodegradation of these structures towards model organic dye (rhodamine 6G) was studied. The synthesized ZnO-based HS were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis and photoluminescence (PL) spectroscopies. The proposed synthesis approaches allow to obtain highly crystalline 3D ZnO, ZnO:Eu3+ and ZnO:Eu3+@Au composites. Results of scanning microscopy show that ZnO flower-like HS are assemblies from smaller components, forming larger ones, the whole ZnO structure was approximately 3 μm. Au nanoparticles (size ∼ 10 nm) are successfully deposited on ZnO HS surface. Luminescent studies show that ZnO is an ideal matrix for incorporation of Eu3+ ions in broad concentration range (Eu3+ = 1.0 at%–5.0 at%) with an efficient red luminescence. The strong UV emission in ZnO, as well as ZnO:Eu3+ HS is observed under 325 nm excitation. Doping of ZnO HS matrix by Eu3+ ions leads to the red shift of deep level emission peak (DLE). The PL intensity reaches the maximum up to 5 at% Eu3+. The photocatalytic properties of ZnO and ZnO:Eu3+@Au HS were investigated under UV–Vis light irradiation towards rhodamine 6G. The obtained results demonstrate the synergetic effect of the deposited gold nanoparticles and Eu3+ doping on photocatalytic activity of ZnO:Eu3+@Au HS in comparison to pristine ZnO and ZnO:Eu3+ HS.

ZnO (nano)structures remain of great interest in biomedical applications due to their unique properties and possible morphologies. Biocompatibility of typically fabricated ZnO structures remains questionable and they still lack desired biological functions, whence their functionalization is of high interest. In this work, we fabricated micro-sized ZnO hierarchical flower-like structures using facile template-free hydrothermal method to act as carriers for the delivery of gold nanoparticles (Au) and/or Biotin (Vitamin B) to cells. Au nanoparticles (~24 nm), as well as Biotin molecules were successfully deposited on the ZnO surface due to non-covalent physical interactions. We have then cultured two cells lines: SH-SY5Y (human malignant neural) and HEK-293 (human non-malignant) and observed that ZnO hierarchical particles exhibited cell line-dependent cytotoxicity. It appeared that further functionalization of ZnO with Au nanoparticles and subsequently with Biotin led to lower discrepancy between the two cell lines response indicating that cytotoxic pathways of pure ZnO were masked by the available surface adsorbed particles (Au/Biotin). Two-photon immunocytochemistry microscopy further confirmed that Biotin decorated particles affected neuroblastoma cells cytoskeleton. These findings contribute to the understanding of cytotoxic pathways of surface-decorated nano-micro-structures made from ZnO with two molecules typically used in anticancer and regenerative medicine therapies.

The internal molecular mobility of a blockbuster antiulcer drug, ranitidine hydrochloride, was extensively studied by referring to the most-stable crystalline form (polymorph II) and the form loade...

According to theoretical predictions, the magnetic properties of MXene structures are determined by the properties of the constitutive transition metals, defects in the MXene layers and the surface functional groups. We studied the magnetic properties of differently functionalized multilayered Ti3C2Tx MXenes and compared them with those of Ti3AlC2 and Ti2AlC MAX phases, as well as titanium carbide (TiC). The influence of the type and concentration of functional groups on MXene's magnetic properties was investigated by studying Ti3C2Tx samples obtained by etching the aluminum layer from the Ti3AlC2 MAX phase using (1) hydrofluoric acid, (2) chlorosulfonic acid and (3) hydrofluoric acid followed by chlorosulfonic acid. The samples prepared by hydrofluoric or chlorosulfonic acid only showed paramagnetic behavior, while MXenes prepared with an assistance of both acids were found to exhibit two different types of radicals and/or defects in the electron paramagnetic spectrum and mixed antiferromagnetic/paramagnetic behavior under external magnetic field of 100 Oe. The appearance of magnetic ordering was assigned to sulfur-based functional groups ( S2 and SO3H) introduced by chlorosulfonic acid. The obtained results confirm that the magnetic properties of Ti3C2Tx MXenes may depend on the type and concentration of terminal functionalities.

Currently marketed drug-eluting stents are non-selective in their anti-restenotic action. New active substance introduction to polymeric stents and vascular grafts can promote early re-endothelialization, crucial in preventing implant restenosis. Additionally, managing material hydrophobicity by blending synthetic polymers limits adverse effects on bulk properties and controls active substance release. However, the influence of hydrophilic synthetic polymer on human cells in the cardiovascular system remains to be determined. In this report, effects of both poly(e-caprolactone) (PCL) fibers hydrophilization with Pluronic P123 (P123) and cilostazol (CIL) loading were studied. Physicochemical and mechanical properties of electrospun tubular structures produced from PCL and PCL/P123 fibers with and without CIL were investigated and compared. Release profiles studies and in vitro cell proliferation assays of electrospun materials were conducted. It was found that P123 located near the surface of electrospun fibers increased the rate of CIL release. PCL formulation sustained human umbilical vein endothelial cells (HUVEC) growth for 48 h. Despite improved hydrophilicity, PCL/P123 formulations were found to reduce HUVEC viability. Both PCL and PCL/P123 materials reduced primary aortic smooth muscle cells (PASM) viability after 48 h. In PCL formulations containing CIL, drug release caused a decrease in PASM viability. P123 blending with PCL was found to be as a useful pre-fabrication technique for modulating surface hydrophobicity of electrospun materials and the release profile of incorporated active substance. The cytotoxicity of P123 was evaluated to improve the design of drug-loaded vascular grafts for cardiovascular applications.

The application of ionic liquids (ILs) has grown enormously, from their use as simple solvents, catalysts, media in separation science, or electrolytes to that as task-specific, tunable molecular machines with appropriate properties. A thorough understanding of these properties and structure–property relationships is needed to fully exploit their potential, open new directions in IL-based research and, finally, properly implement the appropriate applications. In this work, we investigated the structure–properties relationships of a series of alkyltriethylammonium bis(trifluoromethanesulfonyl)imide [TEA-R][TFSI] ionic liquids in relation to their thermal behavior, structure organization, and self-diffusion coefficients in the bulk state using DSC, FT-IR, SAXS, and NMR diffusometry techniques. The phase transition temperatures were determined, indicating alkyl chain dependency. Fourier-transformed infrared spectroscopy studies revealed the structuration of the ionic liquids along with alkyl chain elongation. SAXS experiments clearly demonstrated the existence of polar/non-polar domains. The alkyl chain length influenced the expansion of the non-polar domains, leading to the expansion between cation heads in polar regions of the structured IL. 1H NMR self-diffusion coefficients indicated that alkyl chain elongation generally caused the lowering of the self-diffusion coefficients. Moreover, we show that the diffusion of anions and cations of ILs is similar, even though they vary in their size.

In this study, GNF@ZnO composites (gelatin nanofibers (GNF) with zinc oxide (ZnO) nanoparticles (NPs)) as a novel antibacterial agent were obtained using a wet chemistry approach. The physicochemical characterization of ZnO nanoparticles (NPs) and GNF@ZnO composites, as well as the evaluation of their antibacterial activity toward Gram-positive (Staphyloccocus aureus and Bacillus pumilus) and Gram-negative (Escherichia coli and Pseudomonas fluorescens) bacteria were performed. ZnO NPs were synthesized using a facile sol-gel approach. Gelatin nanofibers (GNF) were obtained by an electrospinning technique. GNF@ZnO composites were obtained by adding previously produced GNF into a Zn2+ methanol solution during ZnO NPs synthesis. Crystal structure, phase, and elemental compositions, morphology, as well as photoluminescent properties of pristine ZnO NPs, pristine GNF, and GNF@ZnO composites were characterized using powder X-ray diffraction (XRD), FTIR analysis, transmission and scanning electron microscopies (TEM/SEM), and photoluminescence spectroscopy. SEM, EDX, as well as FTIR analyses, confirmed the adsorption of ZnO NPs on the GNF surface. The pristine ZnO NPs were highly crystalline and monodispersed with a size of approximately 7 nm and had a high surface area (83 m2/g). The thickness of the pristine gelatin nanofiber was around 1 &micro, m. The antibacterial properties of GNF@ZnO composites were investigated by a disk diffusion assay on agar plates. Results show that both pristine ZnO NPs and their GNF-based composites have the strongest antibacterial properties against Pseudomonas fluorescence and Staphylococcus aureus, with the zone of inhibition above 10 mm. Right behind them is Escherichia coli with slightly less inhibition of bacterial growth. These properties of GNF@ZnO composites suggest their suitability for a range of antimicrobial uses, such as in the food industry or in biomedical applications.

Molecular reorientations in rosuvastatin calcium, a drug that is widely used to prevent cardiovascular disease, were explored thoroughly by means of solid state nuclear magnetic resonance (1H and 13C NMR) combined with calculations of steric hindrances. The experimental results reveal rich internal reorientational dynamics. All relaxation processes were tested in a broad range of temperatures and described in terms of their type and the associated energy barriers. The internal molecular mobility of rosuvastatin calcium can be associated with the reorientational dynamics of four methyl groups, accompanied by reorientation of the isopropyl group. The energy barriers of methyl and isopropyl group reorientation depended on the type of E/Z isomers, while the water content also had a strong influence on the dynamics of the isopropyl group. In the paper, a consistent picture of the molecular dynamics is provided, facilitating our understanding of molecular mobility in this important pharmaceutical solid.

Novel triple-layered trimetallic Au/Pd/Pt nanoparticles (NPs) with a porous Pt shell, showing a hedgehog-like structure, were successfully bounded with TiO2 and NaTaO3 surfaces, and used for photoc...

We present a complex, computationally supported solid-state spectroscopy study, elucidating the local order in a blockbuster anti-ulcer drug, ranitidine hydrochloride form II. To this end, dispersion-corrected periodic density functional theory calculations were combined with powder X-ray diffraction, solid-state nuclear magnetic resonance, and low-frequency vibrational spectroscopy, delivering a refined structural model. We found that a competition of nearly iso-energetic substructures, formed by enamine-type species, gives rise to the formation of several potential polymorphs. The considered models were critically examined in terms of both the stabilization energy and the spectral response. While previous studies left the crystal structure considered to be conformationally disordered at a molecular level, we found that the disorder is realized far beyond the local molecular arrangement, elucidating formation of infinite nets of hydrogen-bonded chains, linking both Z and E enamine fragments. Contrary to ...

The present study is focused on the development of liposomes bearing gadolinium chelate (GdLip) providing two functionalities for magnetic resonance imaging (MRI) and photodynamic therapy of cancer. A lipid derivative of gadolinium(III) diethylenetriamine pentaacetic acid salt (GdDTPA1) was inserted in the liposomal membrane and served as MRI contrast agent whereas a zinc phthalocyanine (ZnPc) was used as a model photosensitizer. In addition to conventional liposomes, pegylated lipids were used for the preparation of "stealth" liposomes. The characterization of different GdLip formulations involved evaluation of the liposomes size by nanoparticle tracking analysis, thermal phase behavior by differential scanning calorimetry and ZnPc-mediated singlet oxygen production. Furthermore, relaxivity measurements were performed as well as cytotoxicity and photodynamic activity against cancerous and normal cell lines was studied. Size and thermal behavior were only slightly influenced by GdLip composition, however it distinctly affected singlet oxygen production of ZnPc-loaded GdLip. The quantum yields of singlet oxygen generation by zinc phthalocyanine incorporated in GdLip containing cationic or/and pegylated lipids were smaller than those obtained for non-pegylated carriers with l-α-phosphatidylglycerol. In general, all formulations of GdLip, irrespectively of composition, were characterized by relaxivities higher than those of commercially used contrast agents (e.g. Magnevist®). NMR study has shown that the incorporation of ZnPc into the formulations of GdLip increases the relaxation parameters r1 and r2, compared to the values for the non-loaded vesicles. GdDTPA1 did not influence the photodynamic activity of ZnPc against HeLa cells.

Block copolymers represent an interesting class of materials, combining properties of individual components and capable of developing nanoscopic domain morphologies. Copolymers which comprise polystyrene and poly(dimethylsiloxane) attract special attention due to their effective segregation and the highly contrasting thermal properties of individual blocks. This work covers structural studies of copolymeric domain architecture and investigates the molecular dynamics observed in bulk PDMS, diblock PS-PDMS and triblock PS-PDMS-PS. Utilization of atomic force microscopy and NMR spin diffusion provide a thorough picture of phase separated systems. Dielectric spectroscopy reveals the dynamic heterogeneity of PDMS amorphous phase. Two distinct structural relaxations, namely α and αc, were observed and attributed correspondingly to PDMS mobile amorphous fraction and PDMS rigid amorphous fraction. Unexpectedly, the segmental reorientations observed in the case of copolymers were faster that that observed for bulk PDMS.

The TiO2 modified by monometallic (Au-TiO2, Pt-TiO2) and bimetallic (Pt/Au-TiO2) NPs have been synthesized by a simple sol-gel method. The optimal dosage of individual components in Pt/Au composition on photocatalytic activity has been systematically investigated. The obtained photocatalysts were thoroughly characterized by BET surface area measurements, UV–vis diffuse-reflectance spectroscopy (DRS), X-ray diffraction analysis (XRD), scanning transmission microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity under visible light (λ > 420 nm and λ > 455 nm) has been estimated in phenol degradation reaction in an aqueous phase. The best photocatalytic activity has been observed for −mono (0.5)Pt_TiO2 and bimetallic (0.5)Pt/(0.5)Au_TiO2 samples with an optimum platinum content. The Pt/Au_TiO2 radical formation mechanism was systematically investigated with the selected scavenger for the degradation process under vis light irradiation. The formation of O 2− with (0.5)Pt/(0.5)Au_TiO2 was established from the high inhibition of phenol degradation. Based on the XPS analysis it was observed that the greater photoactivity of bimetallic sample (0.5)Pt/(0.5)Au_TiO2 could result from a relatively higher content of platinum compared to gold on the surface layer. It must be noted that only platinum takes a significant part in Pt/Au composites on the photoactivity. Furthermore, in this work we present a linear relationship between the crystal size of TiO2 and the reaction rate of Au-TiO2, Pt-TiO2 and Pt/Au-TiO2.

Multimodal nanoparticles (NPs) that may be used for therapies and diagnostics is the most promising trend for efficient therapy. We demonstrate that nanocomposite based on self-organizing silver and ultrasmall magnetic iron oxide NPs (MAg) produced in one-step synthesis revealed unique combination of fluorescence, bactericidal, fungicidal properties and have a potential as magnetic resonance imaging (MRI) contrast agent. Using the green chemistry approach, ginger (Zingiber officinale) rhizome extract was applied as capping agent for MAg synthesis, providing also additional fluorescent properties of NPs and inducing hydrocolloids structuring. The MAg were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive microanalysis (EDS), fluorescence microscopy, cryo-SEM, dynamic light scattering (DLS) techniques, Fourier transform infrared (FTIR) and ultraviolet–visible (UV–Vis) spectroscopies. MAg dispersions in water and some biological media are very stable which is important for biomedical application. The existence of microstructure in MAg hydrocolloids was proved. The hierarchical character and high ordering of this microstructure were discovered and its level-by-level building blocks were investigated. The microstructure was found to be responsible for fluorescence emittance of MAg hydrocolloids. The properties as well as potential application of the MAg hydrocolloids is yet to be discovered. Keywords: Ultrasmall, Silver, Ginger, Nanoparticles, Hydrocolloid, Microstructure

Two polystyrene-b-poly(ethylene oxide) (PS-b-PEO) diblock copolymers differing in molecular mass (49 and 78 kDa) but possessing the same PEO cylindrical morphology are examined to elucidate their molecular dynamics. Of particular interest here is the molecular motion of the PEO blocks involved in the rigid amorphous fraction (RAF). An analysis of complementary thermal calorimetry and X-ray scattering data confirms the presence of microphase-separated morphology as well as semicrystalline structure in each copolymer. Molecular motion within the copolymer systems is monitored by dielectric and nuclear magnetic resonance spectroscopies. The results reported herein reveal the existence of two local Arrhenius-type processes attributed to the noncooperative local motion of PEO segments involved in fully amorphous and rigid amorphous PEO microphases. In both systems, two structural relaxations governed by glass-transition phenomena are identified and assigned to cooperative segmental motion in the fully amorphous phase (the α process) and the RAF (the α

Nanoparticles (NP) string formations on self-assembled copolymeric substrates has been observed. These ”thread of beads” like structures develop via simple colloidal droplet evaporation during meniscus rim withdrawal on polystyrene-block-poly(ethylene oxide) (PS-PEO) copolymer surfaces. It is shown that the process is triggered by the presence of the substrate impurities, which lead to NP aggregate formations serving as string initiation sites. The growth mechanism of these linear structures seems to be capillarity-driven. Moreover, there is an exceptional alignment coupling between NP strips and the block copolymer (BC) domains observed. BC directed NP assembly stems from a gold nanocrystal surface functionalization, which introduces selective affinity for one particular type of BC domain. The presented results reveal a potential fabrication method of NP wires characterized by remarkably low width and thickness comparable with the size of the individual constituent NP.

The main aim of this research was the synthesis of the multimodal hybrid ZnO@Gd 2 O 3 nanostructures as prospective contrast agent for Magnetic Resonance Imaging (MRI) for bio-medical applications. The nanoparticles surface was functionalized by organosilicon compounds (OSC) then, by folic acid (FA) as targeting agent and doxorubicin (Dox) as chemotherapeutic agent. Doxorubicin and folic acid were attached to the nanoparticles surface by amino groups as well as due to attractive physical interactions. The morphology and crystallography of the nanostructures were studied by HRTEM and SAXS techniques. After ZnO nanoparticles surface modification by Gd 3+ and annealing at 900 °C, ZnO@Gd 2 O 3 nanostructures are polydispersed with size 30–100 nm. NMR (Nuclear Magnetic Resonance) studies of ZnO@Gd 2 O 3 were performed on fractionated particles with size up to 50 nm. Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, zeta-potential measurements and energy dispersive X-ray analysis (EDX) showed that functional groups have been effectively bonded onto the nanoparticles surface. The high adsorption capacity of folic acid (up to 20%) and doxorubicin (up to 40%) on nanoparticles was reached upon 15 min of adsorption process in a temperature-dependent manner. The nuclear magnetic resonance (NMR) relaxation measurements confirmed that the obtained ZnO@Gd 2 O 3 nanostructures could be good contrast agents, useful for magnetic resonance imaging.

The molecular dynamics of an ionic liquid (IL) composed of a 1-ethyl-3-methylimidazolium cation and a triflate (trifluoromethanesulfonate) anion, abbreviated as [Emim][TfO], were studied by NMR spectroscopy. By measuring the temperature-dependent high-field 1H and 19F spin-lattice relaxation (SLR) rates, the frequency-dependent 1H and 19F SLR dispersion curves using fast-field-cycling relaxometry, and the temperature-dependent 1H and 19F diffusion constants, and by utilizing the fact that the primary NMR-active nucleus on the Emim cation is 1H, whereas on the TfO anion it is 19F, the cationic and anionic dynamics were studied separately. A single theoretical relaxation model successfully reproduced all the experimental data of both types of resonant nuclei by fitting all the data simultaneously with the same set of fit parameters. Upon cooling, [Emim][TfO] exhibited a supercooled liquid phase between TSL = 256 K and the crystallization temperature TCr ≈ 227–222 K, as confirmed by differential scanning calorimetry (DSC) experiments. Theoretical analysis revealed that within the liquid and the supercooled liquid states of [Emim][TfO], the 1H and 19F relaxation rates are affected by both the rotational and translational diffusional processes with no discontinuous change at TSL. While the rotational diffusion is well described as an Arrhenius thermally activated process, the translational diffusion undergoes strong freezing dynamics that are well described by the Vogel–Fulcher model assuming a freezing temperature of T0 = 157 K. The existence of the supercooled liquid region in the [Emim][TfO] IL should be taken into account when using this IL for a specific application.

Nanocomposites based on block copolymer (BCP) and gold nanoparticles (NPs) filler were measured in terms of their structure and polymer chain molecular dynamics. NPs were functionalized in order to gain selective affinity to one specific type of BCP domain. BCP directed NPs assembly was monitored using atomic force microscopy. Thin nanocomposite films were fabricated via spin-coating technique, annealed and subsequently subjected to reactive ion etching in order to expose inorganic NPs location within the BCP matrix. Selective NPs incorporation was confirmed. Furthermore, interesting NPs distribution in quasi-2D crystallites was revealed. Spectroscopic methods (nuclear magnetic resonance and dielectric spectroscopy) enabled investigation of polymer chain reorientations and estimation of the impact of nano-filler on polymer dynamics. Nanocomposite crystallinity was assessed via thermal analysis and supported by spectroscopic techniques.

The high specific surface area of multilayered two-dimensional carbides called MXenes, is a critical feature for their use in energy storage systems, especially supercapacitors. Therefore, the possibility of controlling this parameter is highly desired. This work presents the results of the influence of oxygen concentration during Ti3AlC2 ternary carbide&mdash, MAX phase preparation on &alpha, Al2O3 particles content, and thus the porosity and specific surface area of the Ti3C2Tx MXenes. In this research, three different Ti3AlC2 samples were prepared, based on TiC-Ti2AlC powder mixtures, which were conditioned and cold pressed in argon, air and oxygen filled glove-boxes. As-prepared pellets were sintered, ground, sieved and etched using hydrofluoric acid. The MAX phase and MXene samples were analyzed using scanning electron microscopy and X-ray diffraction. The influence of the oxygen concentration on the MXene structures was confirmed by Brunauer-Emmett-Teller surface area determination. It was found that oxygen concentration plays an important role in the formation of &alpha, Al2O3 inclusions between MAX phase layers. The mortar grinding of the MAX phase powder and subsequent MXene fabrication process released the &alpha, Al2O3 impurities, which led to the formation of the porous MXene structures. However, some non-porous &alpha, Al2O3 particles remained inside the MXene structures. Those particles were found ingrown and irremovable, and thus decreased the MXene specific surface area.

This work aimed to study for the first time to our knowledge the influence of the structure of the dental flosses (DF) coated by hydroxyapatite nanoparticles (HAP NPs) on the biological performance of saliva probiotic bacteria (S. salivarius), and human dermal and osteoblast-like cells. We used three types of HAP@DF composites (based on two unwaxed dental flosses - “fluffy” and “smooth”, and one waxed “smooth”) with different morphologies. Obtained composites were characterized from the point of view of their structure, morphological characteristics, elemental and chemical composition. We observed that HAP NPs coated “smooth” dental flosses led to an increase of viability and proliferation of oral cavity probiotic bacteria (Streptococcus salivarius) and human cells (dermal fibroblasts and osteoblast-like). In contrast, the highest viability loss of probiotic bacteria (S. salivarius), fibroblasts, and osteoblast-like cells were observed for “fluffy” unwaxed dental flosses due to high cytotoxicity. Our studies showed that HAP NPs significantly improved the biological properties of “fluffy” dental floss. Pristine “smooth” DFs (waxed and unwaxed), as well as all HAP-coated DFs, induced acceptable biocompatibility toward selected human cells.

In this study, the structure of nanoconfined ice and its behavior during the melting process have been investigated. For this purpose, deionized water was inserted into the pores of the ordered carbon structures CMK-3 and CMK-8 having pores of different diameters. The first set of experiments was performed using differential scanning calorimetry (DSC), from which the melting transition temperature of the confined ice was determined. In order to investigate the structure of ice formed inside the mesopores, wide-angle X-ray scattering was used. The measurements were performed at temperatures from 173 K up to and above the pore melting point for each system. The results of the XRD experiments showed features characteristic of both hexagonal, Ih, and cubic, Ic, ice at temperatures below the melting point. The structure of the confined ice corresponds to disordered stacking ice layers, ice Isd, and our results agree well with recent simulations of X-ray diffraction of such ice crystals by Murray and co-workers.

In the present investigation, TiO 2 modified with a different geometry and size of gold particles, such as nanospheres (NSPs), nanostars (NSTs) and nanorods (NRs), were prepared by the immobilization method. The effect of the gold shape, size and TiO 2 matrix type (TiO 2 microspheres or rutile TIO-6_TiO 2 ) were systematically investigated. The obtained photocatalysts were thoroughly characterized by UV–vis diffuse-reflectance spectroscopy (DRS), BET surface area measurements, scanning electron microscopy (SEM), scanning transmission microscopy (TEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity under visible light (λ > 420 nm) has been estimated in phenol degradation reaction in an aqueous phase. The significantly high photocatalytic activity under visible light irradiate as demonstrated by the TiO 2 sample modified by spheres of gold. The average rate of phenol decomposition was 1.9 μmol dm −3 min −1 and was three-times higher compared to the pristine TiO 2 amorphous microspheres. On the other hand the photocatalytic activity was relatively lower and was 0.38 and 0.27 μmol dm −3 min −1 for nanorods and nanostars deposited on the amorphous form of TiO 2 microspheres, respectively. The visible light activity decreased in following order: (NSPs)> (NRs)> (NSTs). The obtained photocatalytic efficiency of samples was ascribed to the geometry and the size effect of the enhanced and the possible mechanism for this was discussed in detail. Furthermore, in this work we show the effect of calcination temperature on the structure of gold NPs, NRs and NSs before and after modification on the morphology and photocatalytic activity of Au-TiO 2 .

Egg-shaped nanoparticles with a core–shell morphology were synthesized by thermal decomposition of an iron oleate complex. XRD and M(T) magnetic measurements confirmed the presence of FeO (wustite) and Fe3O4 (magnetite) phases in the nanoparticles. Oxidation of FeO to Fe3O4 was found to be the mechanism for the shell formation. As-made nanoparticles exhibited high values of exchange bias at 2 K. Oxidation led to decrease of exchange field from 2880 Oe (in as-made sample) to 330 Oe (in oxidized sample). At temperatures higher than the Neel temperature of FeO (200 K) there was no exchange bias. An interesting observation was made showing the exchange field to be higher than the coercive field at temperatures close to magnetite's Verwey transition.

In this investigation, the fabrication of porous core/shell nanostructures consisting of copper (core) and copper-gold nanoalloy (shell) for medical applications is presented. As a core triangular-shaped copper nanoparticles were used. The porous bimetallic nanoshell was prepared via galvanic reaction in the presence of oil-in water emulsion. It was proved that porous nanoalloy layer can be prepared at pH 7 and in the presence 0.1% and 0.5% oil-in water emulsion. The porous structure fabrication was mainly determined by volume fraction of hexadecane to acetone in the oil-in water emulsion and Zeta-potential of emulsion droplets (pH of emulsion). The influence of emulsion droplets size before galvanic reaction on porous structure preparation was negligible. It was found that doxorubicin could be easily introduced and released from porous core/shell nanostructures, due to spontaneous adsorption on the copper-gold nanoporous surface. The in vitro test showed that cytotoxic effect was more prominent once the doxorubicin was adsorbed on the porous copper-gold nanocarriers. It was demonstrated, that doxorubicin-loaded copper-gold nanostructures caused inhibition cell proliferation and viability of cancer cells, in a concentration-dependent manner. The results indicates that presented coper-gold nanocarrier have potential to be used in targeted cancer therapy, due to its porous structure and cytotoxic effect in cancer cells.

Bifunctional nanostructures based on ZnO nanoparticles (NPs) with controlled Gd 2 O 3 shell thicknesses were obtained by simple low-temperature methods (sol–gel technique and seed deposition method). The morphology, nanostructure, phase and chemical composition as well as luminescent and magnetic properties of the obtained core–shell nanostructures were investigated by transmission electron microscopy (HRTEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) techniques, optical spectroscopy, and SQUID magnetometer. As-obtained ZnO NPs are highly monodispersed and crystalline with mean particles size distribution of about 7 nm. Modification of the ZnO NPs surface by Gd 2 O 3 shell leads to an increase of the ZnO particles size up to 80–160 nm and the formation the Gd 2 O 3 shell with size of 2–4 nm. The dependence of the phase composition, luminescent and magnetic properties on Gd 2 O 3 content are also discussed.

ZnO:Tb3+ hierarchical structures (HS) were synthesized via efficient and facile template-free wet chemistry methods - precipitation and solvothermal ones. Obtained Tb3+-doped HS were functionalized by organosilicon compounds (OSC) for use it as a drug carrier to loading of the doxorubicin (Dox). X-Ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectrum (EDS), UV, photoluminescence (PL) and Fourier transform infrared (FT-IR) spectroscopies, nitrogen adsorption/desorption (BET), and cytotoxicity tests were employed to characterize the obtained ZnO and ZnO:Tb3+ HS. Results showed that proposed approach allows to obtain highly crystalline microspheres composed of nanosheets. XRD analysis of the obtained samples showed presence of two-phased system: ZnO and Tb(OH)3. SEM results demonstrated that obtained ZnO:Tb3+ HS have flower-like spherical shape with mean size approximately 4 μm. The Tb3+-doping do not change the original morphology of ZnO HS. The Brunauer-Emmett-Teller (BET) measurements showed that unique morphology allowed to obtain surface area of ZnO/ZnO:Tb3+ HS in range of 5 ÷ 13 m2g-1. ZnO and ZnO:Tb3+ HS showed high drug loading and low cytotoxicity.

Micro/nanostructures, which are assembled from various nanosized building blocks are of great scientific interests due to their combined features in the micro- and nanometer scale. This study for the first time demonstrates that ultrasmall superparamagnetic iron oxide nanoparticles can change the microstructure of their hydrocolloids under the action of external magnetic field. We aimed also at the establishment of the physiological temperature (39 °C) influence on the self-organization of silver and ultrasmall iron oxides nanoparticles (NPs) in hydrocolloids. Consequences of such induced changes were further investigated in terms of their potential effect on the biological activity in vitro. Physicochemical characterization included X-ray diffraction (XRD), optical microscopies (SEM, cryo-SEM, TEM, fluorescence), dynamic light scattering (DLS) techniques, energy dispersive (EDS), Fourier transform infrared (FTIR) and ultraviolet–visible (UV-Vis) spectroscopies, zeta-potential and magnetic measurements. The results showed that magnetic field affected the hydrocolloids microstructure uniformity, fluorescence properties and photodynamic activity. Likewise, increased temperature caused changes in NPs hydrodynamic size distribution and in hydrocolloids microstructure. Magnetic field significantly improved photodynamic activity that was attributed to enhanced generation of reactive oxygen species due to reorganization of the microstructure.

The molecular dynamics of a cardioselective beta-blocker with intrinsic sympathomimetic activity – acebutolol hydrochloride, was investigated by employing spin-lattice relaxation 1H nuclear magnetic resonance (NMR) and quasielastic neutron scattering (QENS) experiments along with periodic density functional theory (DFT) computations. The relaxation experiments reveal the presence of four dynamic processes, further assigned to the methyl groups reorientations. The analyzed motions were characterized in terms of their activation barriers and correlation times, while their assignment was supported by theoretical computations. The earlier reported crystallographic structure reveals intriguing features in the large-size unit-cell, defined by eight molecular units. By combining solid-state DFT calculations with the intermolecular interactions analysis (Hirshfeld Surface; Reduced Density Gradient), the nature of the stabilizing crystal forces has been revealed, emphasizing the role of moderate-strength (N–H⋯O; O–H⋯Cl; N–H⋯Cl) and weak (C–H⋯O) hydrogen-bond contacts. The theoretical computations provide clear support for the assignment of particular motions and interpretation of the experimental data as showing a competing influence of both internal-structure and intermolecular factors on their activation barriers. The highest energy barriers were assigned to the acetyl-related methyl rotors, the intermediate ones are due to the isopropyl part, while the most-dynamic methyl groups are assigned to the alkyl chain. Inclusion of crystallographic forces via calculations in periodic boundary conditions was found to be essential for a proper understanding of both the conformational and dynamic properties of the system under interest, as it could not be achieved with molecular modeling. Therefore, the performance of several semi-local exchange–correlation functional approximations was critically examined, revealing a clear tendency in favor of the ‘soft’ and dispersion-corrected schemes for estimation of the rotational barriers in pharmaceutical solids.

Purpose The study discusses the value of electrospun cilostazol-loaded (CIL) polymer structures for potential vascular implant applications. Methods Biodegradable polycaprolactone (PCL) fibers were produced by electrospinning on a rotating drum collector. Three different concentrations of CIL: 6.25%, 12.50% and 18.75% based on the amount of polymer, were incorporated into the fibers. The fibers were characterized by their size, shape and orientation. Materials characterization was carried out by Fourier Transformed Infrared spectroscopy (FTIR), Raman spectroscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). In vitro drug release study was conducted using flow-through cell apparatus (USP 4). Results Three-dimensional structures characterized by fibers diameter ranging from 0.81 to 2.48 μm were in the range required for cardiovascular application. DSC and XRD confirmed the presence of CIL in the electrospun fibers. FTIR and Raman spectra confirmed CIL polymorphic form. Elastic modulus values for PCL and the CIL-loaded PCL fibers were in the range from 0.6 to 1.1 GPa. The in vitro release studies were conducted and revealed drug dissolution in combination with diffusion and polymer relaxation as mechanisms for CIL release from the polymer matrix. Conclusions The release profile of CIL and nanomechanical properties of all formulations of PCL fibers demonstrate that the cilostazol loaded PCL fibers are an efficient delivery system for vascular implant application. Electronic supplementary material The online version of this article (10.1007/s11095-017-2314-0) contains supplementary material, which is available to authorized users.

Magnetite nanoparticles (NPs) decorated with silver (magnetite/Ag) are intensively investigated due to their application in the biomedical field. We demonstrate that the increase of silver content on the surface of nanoparticles improves the adsorptivity of antibiotic rifampicin as well as antibacterial properties. The use of ginger extract allowed to improve the silver nucleation on the magnetite surface that resulted in an increase of silver content. Physicochemical and functional characterization of magnetite/Ag NPs was performed. Our results show that 5%-10% of silver content in magnetite/Ag NPs is already sufficient for antimicrobial properties against Streptococcus salivarius and Staphylococcus aureus. The rifampicin molecules on the magnetite/Ag NPs surface made the spectrum of antimicrobial activity wider. Cytotoxicity evaluation of the magnetite/Ag/rifampicin NPs showed no harmful action towards normal human fibroblasts, whereas the effect on human embryonic kidney cell viability was time and dose dependent.

Multicomponent TiO2-based nanomaterials (MC-NMs) show better physicochemical properties than their individual components or bulk materials. However, the same unique properties that offer innovative applications might also pose unknown risks to human health and the environment. In this context, TiO2-based nanomaterials with a mixture of noble metal precursors (Ag, Au, Pt, and Pd) for large-scale technological applications in air purification were designed, synthesized and characterized. The influence of the type and amount of noble metal precursor on the optical properties and photocatalytic activity of MC-NMs and their toxicity to mouse embryo fibroblast cell line (BALB/3T3), human lung cell line (A549) and human liver cell line (HepG2) was investigated. A hazard assessment of the designed TiO2-based MC-NMs was performed for the first time according to the standards developed under the Joint Research Center and NANoReg2 project (Horizon 2020). The threshold concentration of monometallic NPs that ensure high photocatalytic activity without increasing hazard to humans and the environment was determined. The results indicated that the most effective sample is represented by the 0.1Ag_0.1Au_0.1Pt_1Pd/TiO2 photocatalyst, in which noble metal NPs demonstrated a synergistic effect on photocatalytic activity without increasing the toxicity (safe MC-NMs with 86% toluene degradation after 1 h of irradiation, efficiency 5 times higher than that of pristine TiO2). The obtained results confirm that systematic knowledge and proper manipulation of component concentration may lead to rational design of safe TiO2-based MC-NMs with wide application in air purification under solar energy.

Two mesoporous silica materials: MCM-41 and SBA-15 were applied as potential nanocarriers for poorly soluble drug—nimodipine. Drug incorporation was performed using modified adsorption from the solution method and loaded samples before and after washing procedure were studied. The physical properties were verified by: differential scanning calorimetry, X-ray powder diffraction, electron microscopies (SEM/TEM) and Fourier-transform infrared spectroscopy (FT-IR). FT-IR results for bulk nimodipine were interpreted on the basis of first principles calculations (DFT). As a result of encapsulation process, in both matrices nimodipine appeared simultaneously in two forms: crystalline and amorphous, but the first one turned out to be easily removable during washing procedure. The in vitro dissolution and release tests were performed with ultra pure water under supersaturating conditions. The release rate of the amorphous nimodipine from mesoporous silica materials was at least 70 times higher than dissolution rate of bulk drug, thus revealed a potential usefulness of such carrier in future pharmaceutical applications in terms of delivery of poorly soluble drugs.