Current Nanoscience (v.10, #6)

Human Mesenchymal Stromal Cell Enhanced Morphological Polarization by Contact Interaction with Polyethylene Terephthalate Nanogratings by Sara Antonini, Martino Alfredo Cappelluti, Sandro Meucci, Emanuela Jacchetti, Orazio Vittorio, Paolo Parchi, Michele Lisanti, Simone Pacini, Mario Petrini, Fabio Beltram, Marco Cecchini (773-778).
Understanding how the substrate topography acts on human bone marrow-derived mesenchymal stromal cells(MSCs) can help the rational design of scaffolds for improving bone regeneration protocols. MSCs are highly sensitive tothe extracellular physical properties and can be successfully manipulated by simple contact interaction with supportingsubstrates. To this end, some polymeric materials were introduced, but polyethylene terephthalate (PET), a thermoplasticpolymer approved by the US Food and Drug Administration for clinical use and very attractive in terms of biocompatibilityand mechanical properties, has not been tested yet in terms of cell mechanotransduction. Here, we propose PETnanogratings (alternating lines of submicron ridges and grooves) as scaffolds for stimulating mechanotransductionmechanisms. Low-temperature hot embossing is exploited as fabrication method, and standard oxygen plasma activationas functionalization to improve cell adhesion and spreading. We show that the substrate directionality stimulus is optimallydelivered to the MSCs, which in turn elongate and align to the nanograting lines. Finally, we verify that this polarizationoccurs also at level of cytoskeleton fibers and, though to a lesser extent, of nuclei.

Preparation and Application of Mucoadhesive Nanoparticles Containing Enoxaparin in a Wound Healing Animal Model by Stephany Cares Huber, Priscyla Daniely Marcato, Nelson Duran, Andrea Monte Alto Costa, Joyce Maria Annichino-Bizzacchi (779-785).
The use of heparin or low molecular weight heparin (LMWH) is calling attention as an alternative for treatingof skin ulcers. However, clinical topical application heparin has challenges such as stability, permeation and number ofadministrations. Thus, the encapsulation of heparin in nanoparticles may enable the clinical application of this moleculefor the treatment of lesions. Therefore, the goal of this study was evaluated the use of free and encapsulated LMWH inmucoadhesive nanoparticles on acute skin lesions in an in vivo rat model. The polymeric nanoparticles was prepared usingpoly(ε-caprolactone) and chitosan in order to obtain a particle with mucoadhesive properties. Spherical nanoparticleswith an average diameter of 511 nm and with positive superficial charge (+ 20 mV) were produced. In vivo experimentswith free or encapsulated enoxaparin showed no beneficial effect upon the size of the skin lesions in comparison tocontrols. Furthermore, no renal, hepatic or hematological toxicity was detected in all groups analyzed. In conclusion,mucoadhesive particles with high encapsulation efficiency (98%) were produced, however with no favorable effect forthe treatment of acute skin wounds.

Development of New Babassu Oil Lipidic Nanostructured Systems; Potential Alternative for Benign Prostatic Hyperplasia Therapy by Lilian Henriques do Amaral, Rita de Cassia Ascencao Barros, Samantha Soares Barbosa, Leticia Coli Louvisse Abreu, Flavia Almada do Carmo, Helena Carla Castro, Luiz Eurico Nasciutti, Carlos Rangel Rodrigues, Valeria Pereira de Sousa, Lucio Mendes Cabral (786-795).
This study investigates new lipidic nanocarrier preparations for production of babassu oil formulations, whichare indicated as less radical herbal therapeutic alternatives for the prevention of benign prostatic hyperplasia. The babassuoil was obtained in high yield using the previously studied, reproducible soxlhet extraction process. We investigated thepreparation of nanostructured babassu oil lipid carriers and babassu oil nanoemulsions, to determine conditions that yielda high percentage of babassu oil encapsulation, have appropriate size distribution and zeta potential for vectorization ofbabassu oil to the prostate. Cytotoxicity tests were performed using intestinal epithelial Caco-2 cells and J-774 macrophages,which indicated that nanostructured lipid carriers for babassu oil are not toxic to front Caco-2 cells and are able toreduce J774 cell viability. This indicates their potential use for treatment against inflammatory processes such as prostatitisand for administration through the oral route. Whereas, in previous studies conducted by our research group, other babassuoil nanosystems showed activity when tested in cell strains of human benign prostatic hyperplasia lineage. The newbabassu oil nanostructured lipid carriers prepared in this study can be used as a new prototype for phytotherapic nanoformulationsfor the prophylaxis of prostate pathologies, since they are highly lipophilic, have narrow size distribution andhave low toxicity.

Investigation of ZnS Nanoparticle Antibacterial Effect by G.R. Amir, S. Fatahian, N. Kianpour (796-800).
ZnS (Zinc Sulfide) nanoparticles (2-4 nm) were synthesized by chemical precipitation method. Their characteristicsand physical properties were evaluated by scanning tunneling microscopy, ultraviolet-visible spectrophotometry andX-ray diffraction. It was found that the synthesized ZnS nanoparticles are cubic of high-quality. Moreover, it was realizedthat ZnS optical properties are related to the environment temperature. Antibacterial effects of ZnS nanoparticles againstsome pathogen bacteria were studied. Pseudomonas aeruginosa, Actinomycete and Salmonella typhi were used as test microorganisms.Disc bacteriological tests were performed in order to assess the effects of ZnS concentration (0.3 to50 mg/mL) as antibacterial agent. The inhibition zone diameter was directly and strongly related to the nanoparticle concentrationand Actinomycete was the most affected bacteria.

Study of the Interaction Between Graphene Oxide and Surface-confined Biomolecules to Develop New Kind of Biosensors by Xiaoxi Li, Peng Miao, Limin Ning, Tao Gao, Zonghuang Ye, Genxi Li (801-806).
In this work, we have studied the interaction between graphene oxide (GO) and the biomolecules immobilizedon an electrode surface, which has been further employed to develop new kind of biosensors by fabricating gammaglutamyltransferase(γ-GGT) sensor as an example. Specifically, glutathione (GSH) is firstly immobilized on the surfaceof a gold electrode, and GO nanosheet is introduced to recognize the charge change of GSH caused by the catalysis of?-GGT. Then, the introduction of reductant and Ag+ induces silver deposition and partial reduction of GO, forming GOAgNPscomplex for electrochemical readout. Since this complex may have excellent electric conductivity and the solidstatevoltammetry of Ag/AgCl can provide a well-defined symmetrically sharp silver stripping peak, a sensitive electrochemicalbiosensor for the detection of γ-GGT is thus developed. Moreover, the experimental results obtained in this workindicate that GO itself can serve as a general recognition element for biosensor fabrication and GO-AgNPs can be a promisingmaterial in a general sensing platform, so such kind of more biosensors can be developed in the future.

Heat Transfer Analysis on Transport of Copper Nanofluids Due to Metachronal Waves of Cilia by Noreen Sher Akbar, Adil Wahid Butt, N.F.M. Noor (807-815).
The purpose of present investigation is to describe ciliary motion of the transport of fluids in human bodybased on the mathematical model of the copper nanofluid with pure water as the base fluid. We considered that the groupof cilia operate together and produce metachronal waves to transport the fluid at the walls of a tube of finite length. Theexpressions for exact solutions of the aforementioned problem have been obtained and the results have been discussedgraphically for velocity, temperature and pressure gradient for different physical quantities.

Development of Sustained Release "Nanopolypill" of Ischemic Heart Disease Drugs - An Experimental Study by Anjuman Arora, Nusrat Shafiq, Sanjay Jain, G.K. Khuller, Sadhana Sharma, Avaneesh K. Pandey, Samir Malhotra (816-826).
Background: The present study was planned to formulate, characterize and evaluate the pharmacokinetics of anovel “nanopolypill” comprising four commonly prescribed cardiovascular drugs, atorvastatin, aspirin, atenolol and candesartan.;Methods: The candidate drugs were loaded in Poly (DL-lactide-co-gycolide) (PLGA) by emulsion- diffusion-evaporationmethod. The formulations were evaluated for their size, morphology, drug loading and in vitro release individually. Singledose pharmacokinetic profiles of the nanoformulations alone and in combination, as a nanopolypill, were evaluated inWistar rats.;Results: The candidate drugs were encapsulated inside PLGA with entrapment efficiencies ranging from 27.8%, 33.5%,47.5% and 62.9% for aspirin, candesartan, atenolol and atorvastatin respectively. The nanoparticles ranged in size from 50to 169 nm. In vitro release profile of the nanoformulation showed 100% release by day 6 in the physiological pH 7.4 setup with PBS (phosphate buffer saline) and by day 4-5 in the intestinal pH 1.2 and 8.0 set up SGF (simulated gastric fluid)and SIF (simulated intestinal fluid) respectively. In pharmacokinetic analysis a sustained-release for 6 days and significantincrease in the mean residence time (MRT), as compared to the respective free drugs was noted [MRT of atorvastatin, atenolol,aspirin and candesartan changed from 12.9 to 75.75 hours, 8.5 to 74.19 hours, 15.8 to 53.06 hours, and 12.6 to94.92 hours respectively].;Conclusions: We have shown for the first time that encapsulating atorvastatin, aspirin, atenolol and candesartan into asingle nanoformulation, to get the “nanopolypill” is a feasible strategy which has a potential of decreasing pill burden.

Zinc Oxide (ZnO) nanowires were produced by using the seed layer deposition, RF cylindrical magnetron sputteringand sol-gel spin coating techniques. The ZnO seed layer films were characterized by atomic force microscopy(AFM) and ellipsometry. The ZnO nanowires were characterized by scanning electron microscopy (SEM), energy dispersivespectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Deposition of ZnO seedlayer films using the RF cylindrical magnetron sputtering technique produced the best aligned c-axis orientated nanowireswith uniform dimensions. An increase in the gold (Au) film layer thickness produced nanowires of smaller diameter andless orientation in the c-axis. Polycrystalline Au film layer increased the mean diameter of the ZnO nanowires without effectingthe c-axis orientation. This study provided valuable information in controlling the dimensions and alignment ofZnO nanowires.

TiO2 photocatalysts doped with three transition metal ions of varying concentration were prepared by adsorptionphase synthesis. The influence of different metal ion species and contents on the morphology and crystallization ofTiO2 sintered under various temperatures was explored by transmission electron microscopy, X-ray diffractometry, UVvisspectroscopy, and X-ray photoelectron spectroscopy. Photodegradation experiments on methyl-orange were employedto evaluate photocatalytic activity. Results indicated that 0.05 at.% Fe3+ and Cd2+ doping introduces lattice distortions asshallow trapping sites; moreover, doping improved the activity of adsorption phase synthesis (APS) catalysts. TiO2 crystallizationwas restricted when the doping content was greater than 0.05 at.% because other metal ions destroy the TiO2 lattice structure. Restriction also increased with doping content. An optimum doping content was observed during thepreparation of TiO2 doped with Cd2+ and Fe3+. As the Fe3+ radius is close to the Ti4+ radius, the influence of Fe3+ dopingcontent on TiO2 crystallization and activity was more apparent than that of Cd2+ doping content. Increases in sinteringtemperature resulted in fewer lattice distortions acting as shallow trapping sites and decreases in APS catalyst activities.

Partial Slip Effects on a Rotating Flow of Two Phase Nano Fluid Over a Stretching Surface by S. Nadeem, Aziz Ur Rehman, Rashid Mehmood, M. Adil Sadiq (846-854).
The main objective of the present study is to discuss the slip-flow of a rotating nanofluid over a stretchingsheet. The two phase nanofluid model is used for the physical modeling of the system. Using suitable similarity transformations,governing partial differential equations are reduced into three coupled ordinary differential equations. Theseequations are then solved numerically using mid-point integration scheme along with Richardson extrapolation via Maple[26-28]. Influence of non-dimensional slip parameter K, rotation parameter γ and nanoparticle volume fraction Φ on velocity,temperature and skin frictions have been tabularized, demonstrated graphically and discussed. In order to validateour numerical scheme, skin friction coefficients and local heat flux are computed in the absence of slip and rotation andthey are found to be in very good agreement with the previously published literature.

Hydroxyapatite nanoparticles (HAP) were surface-grafted with poly(?-caprolactone) (PCL) using two types ofhydroxyl groups: inherent hydroxyl groups within HAP and hydroxyl groups of poly(2-hydroxyethyl methacrylate)(PHEMA) grafted on the HAP surface by atom transfer radical polymerization (ATRP). The grafting efficiency and theamount of grafted polymer were evaluated by thermal gravimetric analysis (TGA). The colloidal stability testingsuggested that the surface-grafted HAP retained higher dispersibility in methylene chloride than pure HAP nanoparticlesdid. Moreover, the dispersity of the modified particles was significantly improved with the increasing amount of PCLgrafted. The composite scaffolds of PCL and surface-grafted HAP exhibited enhanced compressive strength and modulus,which was attributed to the increased interfacial interaction between PCL and surface-modified HAP. In particular, it wasfound that the compressive modulus of the surface-grafted HAP with 47.2 wt% PCL was 91.6% higher than that of pureHAP mixed with PCL scaffold.

The MHD Peristaltic flow and nanofluid with Newtonian heating in asymmetric channel are considered. Thegoverning coupled equations are constructed “under long wavelength and low Reynold's number approximation”. TheNewtonian heating is controlled by a dimensionless conjugate parameter, which varies between walls of channel. HPMsolutions are evaluated for nano particle fraction and heat transfer, while exact solutions are computed for stream functionand pressure gradient. The important findings in this study are the variation of the “conjugate parameter for Newtonianheating γ Hartman number M, thermophoresis parameter Nt and Brownian motion parameter Nb on pressure rise, nano particlefraction, heat transfer phenomena, pressure gradient and streamlines”. The velocity field rises due to rise in M closethe channel ramparts though velocity field declines at the centre of the canal.

Correlation Between Size of CoFe2O4 Nanoparticles Determined from Experimental and Calculated Data by Different Mathematical Models by Danut Gabriel Cozma, Daniel Gherca, Ionut Mihalcea, Constantin Virlan, Nicoleta Cornei, Aurel Pui (869-876).
This study reports the synthesis of CoFe2O4 nanoparticles by coprecipitation method in the presence of LinseedOil as surfactant. The capping agent was used to stabilize the particles and prevent their agglomeration. The characterizationstudies were conducted by in situ X-ray diffraction, transmission electron microscopy, thermal analysis (TG-DTA)and FTIR spectroscopy. The average particle sizes obtained by XRD data were used to obtain a correlation with size ofCoFe2O4 nanoparticles determined, using mathematical equations based on different models. The statistical studies showthat the cubic model gives a good correlation within the whole temperature range (100 - 850 °C). The result of these investigationswas very useful for establishing the optimal calcination temperature. FT-IR spectroscopy and thermogravimetricanalysis (TG) showed that the core-shell structure type of CoFe2O4 nanoparticles is stable below this annealingtemperature. TEM analysis indicates that the CoFe2O4 samples during the calcinations treatment were spherical in shapeand uniform in morphology and particles size.

Experimental Realization of TiO2 Nanosponge/Spin-coated P3HT Heterojunction Solar Cells by Fabiano Thomazi, Mariana Rossi de Souza, Cyro K. Saul, G.A. Viana, F.C. Marques, Rodrigo G.M. Silvestre, Marcos A. Brehm, C.E.B. Marino, E. Burkarter, C.A. Dartora (877-882).
Production and characterization of multilayered polymer solar cells consisting of P3HT thin films deposited ontitanium dioxide nanosponges are reported. The photovoltaic response is remarkable, considering the simplicity of the thinfilm production method employed here. The nanostructured TiO2 anodic films were grown in buffered aqueousphosphoric acid solutions under potentiostatic regime at room temperature and then characterized using scanning electronmicroscopy. The P3HT films were prepared by spin coating technique and the samples were annealed at 180°C.Conversion efficiencies around 0.4% were obtained, with open circuit voltages and short circuit current densities as highas 560 mV and 2.7 mA/cm2, respectively.

Symmetrical Dipole Contribution from Planar Defects on m-plane ZnO Epitaxial Films by Chung-Wei Liu, Shoou-Jinn Chang, Yen-Teng Ho, Li Chang, Kuang-Yao Lo, Sanjaya Brahma (883-888).
The planar defects such as basal stacking faults (BSFs) are probed on m-plane ZnO grown on LaAlO3(112)substrate by reflective second harmonic generation (RSHG). The BSFs result in nonvanishing single-direction dipoles thatbehave similar to a mirror-like symmetrical dipole. The RSHG pattern from m-plane ZnO comprised of not only the bulkdipole contribution of ZnO but also an additional mirror-like symmetrical dipole contribution from BSF defects. Transmissionelectron microscopy image displays the presence of BSFs that lie in the c-plane of ZnO and agrees well withRSHG results. Planar BSFs are formed due to the anisotropic stress relaxation between m-plane ZnO film andLaAlO3(112) substrate, resulting in higher-quality m-plane ZnO films.