scholarly journals Influence of Magnetic Micelles on Assembly and Deposition of Porphyrin J-Aggregates

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 187 ◽  
Author(s):  
Maria Angela Castriciano ◽  
Mariachiara Trapani ◽  
Andrea Romeo ◽  
Nicoletta Depalo ◽  
Federica Rizzi ◽  
...  
Keyword(s):  
Water Solubility ◽  
Superparamagnetic Iron Oxide ◽  
Linear Dichroism ◽  
Water Soluble ◽  
Hydrophobic Core ◽  
Force Microscopy ◽  
Atomic Force ◽  
Acidic Conditions ◽  
J Aggregates ◽  
High Degree

Clusters of superparamagnetic iron oxide nanoparticles (SPIONs) have been incorporated into the hydrophobic core of polyethylene glycol (PEG)-modified phospholipid micelles. Two different PEG-phospholipids have been selected to guarantee water solubility and provide an external corona, bearing neutral (SPIONs@PEG-micelles) or positively charged amino groups (SPIONs@NH2-PEG-micelles). Under acidic conditions and with specific mixing protocols (porphyrin first, PF, or porphyrin last, PL), the water-soluble 5,10,15,20-tetrakis-(4-sulfonatophenyl)-porphyrin (TPPS) forms chiral J-aggregates, and in the presence of the two different types of magnetic micelles, an increase of the aggregation rates has been generally observed. In the case of the neutral SPIONs@PEG-micelles, PL protocol affords a stable nanosystem, whereas PF protocol is effective with the charged SPIONs@NH2-PEG-micelles. In both cases, chiral J-aggregates embedded into the magnetic micelles (TPPS@SPIONs@micelles) have been characterized in solution through UV/vis absorption and circular/linear dichroism. An external magnetic field allows depositing films of the TPPS@SPIONs@micelles that retain their chiroptical properties and exhibit a high degree of alignment, which is also confirmed by atomic force microscopy.

Self-Assembled TPPS4 Nanostructures Revealed by Atomic Force Microscopy

2004 ◽  
Vol 97-98 ◽  
pp. 191-194 ◽  
Author(s):  
R. Augulis ◽  
Valentinas Snitka ◽  
R. Rotomskis
Keyword(s):  
Atomic Force Microscopy ◽  
Spatial Structure ◽  
Water Soluble ◽  
Silicon Substrates ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean ◽  
J Aggregates ◽  
Self Assembled ◽  
Experimental Findings

Meso-tetra (4-sulfonatophenyl) porphine (TPPS4) is water-soluble tetrapyrrolic dye, which forms self assembled nanostructures – J-aggregates under appropriate conditions. It was shown, that such aggregates survive dried on the substrate. The spatial structure of TPPS4 Jaggregates formed in acidic aqueous solutions and dispersed on silicon substrates was analyzed by means of atomic force microscopy (AFM). The stripe-like structures were observed. The size of individual stripes ranged 4,5×40×(200-1000) nm (H×W×L). The width and height was almost the same for all stripes and independent upon the concentration of the solution, however the length was statistically distributed and the mean length increased with increasing concentration of initial TPPS4 solution. At higher concentrations such stripes stacked into thicker fibers containing 2-20 stripes. Such fibers branched and formed large bush-like structures sized up to several millimeters. According to experimental findings the model of mesostructures, formed by TPPS4 J-aggregates, was proposed.

Targeting Breast Cancer Cells with G4 PAMAM Dendrimers and Valproic Acid Derivative Complexes

2020 ◽  
Vol 20 (15) ◽  
pp. 1857-1872
Author(s):  
Alberto M. Muñoz ◽  
Manuel J. Fragoso-Vázquez ◽  
Berenice P. Martel ◽  
Alma Chávez-Blanco ◽  
Alfonso Dueñas-González ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Cell Lines ◽  
Water Solubility ◽  
Md Simulations ◽  
Pamam Dendrimer ◽  
Pamam Dendrimers ◽  
Force Microscopy ◽  
Micromolar Concentration ◽  
Atomic Force

Background: Our research group has developed some Valproic Acid (VPA) derivatives employed as anti-proliferative compounds targeting the HDAC8 enzyme. However, some of these compounds are poorly soluble in water. Objective: Employed the four generations of Polyamidoamine (G4 PAMAM) dendrimers as drug carriers of these compounds to increase their water solubility for further in vitro evaluation. Methods: VPA derivatives were subjected to Docking and Molecular Dynamics (MD) simulations to evaluate their affinity on G4 PAMAM. Then, HPLC-UV/VIS, 1H NMR, MALDI-TOF and atomic force microscopy were employed to establish the formation of the drug-G4 PAMAM complexes. Results: The docking results showed that the amide groups of VPA derivatives make polar interactions with G4 PAMAM, whereas MD simulations corroborated the stability of the complexes. HPLC UV/VIS experiments showed an increase in the drug water solubility which was found to be directly proportional to the amount of G4 PAMAM. 1H NMR showed a disappearance of the proton amine group signals, correlating with docking results. MALDI-TOF and atomic force microscopy suggested the drug-G4 PAMAM dendrimer complexes formation. Discussion: In vitro studies showed that G4 PAMAM has toxicity in the micromolar concentration in MDAMB- 231, MCF7, and 3T3-L1 cell lines. VPA CF-G4 PAMAM dendrimer complex showed anti-proliferative properties in the micromolar concentration in MCF-7 and 3T3-L1, and in the milimolar concentration in MDAMB- 231, whereas VPA MF-G4 PAMAM dendrimer complex didn’t show effects on the three cell lines employed. Conclusion: These results demonstrate that G4 PAMAM dendrimers are capableof transporting poorly watersoluble aryl-VPA derivate compounds to increase its cytotoxic activity against neoplastic cell lines.

scholarly journals The effect of replacing iron atoms instead of zinc of the quaternary compound CZTS

2021 ◽  
Vol 2114 (1) ◽  
pp. 012033
Author(s):  
Abubaker.S. Mohammed
Keyword(s):  
Full Width Half Maximum ◽  
Energy Gap ◽  
Film Surface ◽  
X Ray Diffraction ◽  
Quaternary Compound ◽  
Force Microscopy ◽  
Atomic Force ◽  
Coating Method ◽  
Degree Of Crystallization ◽  
High Degree

Abstract In this article, the quaternary compound Cu2MSnS4 was prepared in a simple and inexpensive approach, where M is the iron (Fe) and zinc (Zn) atoms by the spin coating method on a glass substrate at room temperature (RT), as a result of replacing Zn atoms by Fe. Quaternary Cu2ZnSnS4 (CZTS) and Cu2FeSrS4 (CFTS) structural and optical properties have been studied successfully. The material has been identified by X-ray diffraction, and it was discovered that CZTS has a polycrystalline Tetragonal (kesterite) structure, whereas CFTS has a Tetragonal (stannite) structure. A reduction in the full width half maximum (FWHM) of the preferred plane implies a high degree of crystallization. The structural properties of the film surface, such as grain size and roughness, were studied by Atomic force microscopy (AFM). The results explain an increase in nanoparticle size and surface roughness when Fe is substituted by Zn in the CZTS structure. The absorption coefficient values of all designed compounds in visible regions are greater than 104/cm, and the results show that the absorbance coefficient increases with Fe add. The CZTS films showed an energy gap of 1.88 eV, and this value became 1.69 eV with substituted Fe instead of Zn.

scholarly journals C60 Fullerene as an Effective Nanoplatform of Alkaloid Berberine Delivery into Leukemic Cells

Pharmaceutics ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 586 ◽  
Author(s):  
Anna Grebinyk ◽  
Svitlana Prylutska ◽  
Anatoliy Buchelnikov ◽  
Nina Tverdokhleb ◽  
Sergii Grebinyk ◽  
...  
Keyword(s):  
Native American ◽  
Water Solubility ◽  
Middle Eastern ◽  
Leukemic Cells ◽  
C60 Fullerene ◽  
Force Microscopy ◽  
Molar Ratios ◽  
Atomic Force ◽  
Vis Spectroscopy

A herbal alkaloid Berberine (Ber), used for centuries in Ayurvedic, Chinese, Middle-Eastern, and native American folk medicines, is nowadays proved to function as a safe anticancer agent. Yet, its poor water solubility, stability, and bioavailability hinder clinical application. In this study, we have explored a nanosized carbon nanoparticle—C60 fullerene (C60)—for optimized Ber delivery into leukemic cells. Water dispersions of noncovalent C60-Ber nanocomplexes in the 1:2, 1:1, and 2:1 molar ratios were prepared. UV–Vis spectroscopy, dynamic light scattering (DLS), and atomic force microscopy (AFM) evidenced a complexation of the Ber cation with the negatively charged C60 molecule. The computer simulation showed that π-stacking dominates in Ber and C60 binding in an aqueous solution. Complexation with C60 was found to promote Ber intracellular uptake. By increasing C60 concentration, the C60-Ber nanocomplexes exhibited higher antiproliferative potential towards CCRF-CEM cells, in accordance with the following order: free Ber < 1:2 < 1:1 < 2:1 (the most toxic). The activation of caspase 3/7 and accumulation in the sub-G1 phase of CCRF-CEM cells treated with C60-Ber nanocomplexes evidenced apoptosis induction. Thus, this study indicates that the fast and easy noncovalent complexation of alkaloid Ber with C60 improved its in vitro efficiency against cancer cells.

Characteristics of Electron Transport Study of Composited Graphene-Zinc Oxide Thin Film Photoanode for Dye-Sensitized Solar Cells

2020 ◽  
Vol 307 ◽  
pp. 185-191
Author(s):  
Noor Syafiqah Samsi ◽  
N.A.S. Affendi ◽  
M.K. Yaakob ◽  
M.F.M. Taib ◽  
A. Lepit ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Dye Sensitized Solar Cells ◽  
Xrd Analysis ◽  
Oxide Thin Film ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Zno Nanosheets ◽  
High Degree ◽  
Sensitized Solar Cells

Graphene-Zinc Oxide (Gr-ZnO) nanocomposites films were successfully synthesized via facile electrodeposition method in an aqueous solution under Gr concentration conditions. Gr, as a highly conductive carbon, acts as an anchor for ZnO nanosheets and plays a substantial role in controlling the degree of dispersion of ZnO nanosheets onto indium-doped tin oxide (ITO) substrate to form Gr-ZnO nanocomposite. Atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) analysis of Gr-ZnO nanocomposite samples confirmed that the presence of ZnO nanosheets with a high degree of dispersity and crystallinity which is well linked to the thin layer of Gr nanoparticle on ITO substrate. The surface roughness of the films found increased to ~270 nm on Gr-ZnO as compared to Gr ~44 nm and ZnO ~3 nm. Further, the x-ray diffraction spectroscopy (XRD) analysis showed the result is in good agreement with Raman spectroscopy study. The cyclic voltammetry (CV) of Gr-ZnO nanocomposite revealed that the effect of electron-hole recombination process was increased and the presence of Gr in ZnO photoanode provides the fastest redox reaction and hence offers the fastest electron transfer in photoanode.

scholarly journals Optical and Morphological Studies of Thermally Evaporated PTCDI-C8 Thin Films for Organic Solar Cell Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ronak Rahimi ◽  
V. Narang ◽  
D. Korakakis
Keyword(s):  
Thin Films ◽  
Silicon Substrates ◽  
High Electron ◽  
Ambient Conditions ◽  
Force Microscopy ◽  
Morphological Studies ◽  
Atomic Force ◽  
Organic Semiconductor Devices ◽  
Thermal Evaporator ◽  
High Degree

PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient) have been extracted from the spectroscopic ellipsometry (SE). X-ray reflectivity (XRR) and atomic force microscopy (AFM) were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization.

Novel vapor phase method for making ultra thin conformal films of polytetrafluoroethylene (PTFE)

2007 ◽  
Vol 992 ◽  
Author(s):  
Sushant Gupta ◽  
Arul Arjunan Chakkaravarthi ◽  
Rajiv Singh ◽  
Jeff Opalko ◽  
Deepika Singh
Keyword(s):  
Chemical Nature ◽  
Phase Method ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Contact Angle Measurements ◽  
Pulsed Electron Deposition ◽  
Afm Micrographs ◽  
High Degree ◽  
Deposition Conditions

AbstractUltra-thin conformal polytetrafluoroethylene (PTFE) films were prepared by a novel physical vapor technique i.e., pulsed electron deposition (PED) technique. Prepared PTFE or Teflon thin films show high degree of conformity on patterned substrates. Under optimized deposition conditions the films exhibit superhydrophobicity. The PED processed films were characterized using scanning electron microscopy (SEM) and atomic force microscopy (AFM) micrographs and the surface morphology and the conformal nature of the films were studied. The chemical nature and hydrophobicity were studied by FTIR and contact angle measurements, respectively.

Atomic Force Microscopy of Self-Assembled Nanostructures of TPPS4 on SAM Substrates

2004 ◽  
Vol 97-98 ◽  
pp. 195-200 ◽  
Author(s):  
R. Augulis ◽  
R. Valiokas ◽  
B. Liedberg ◽  
R. Rotomskis
Keyword(s):  
Atomic Force Microscopy ◽  
Substrate Surface ◽  
Self Assembled Monolayer ◽  
Force Microscopy ◽  
Polar Groups ◽  
Atomic Force ◽  
Adsorption Of Organic Molecules ◽  
J Aggregates ◽  
Self Assembled ◽  
Highly Correlated

The adsorption of organic molecules on solid surfaces is one of the fundamental processes for the development of molecular-based nanodevices. Here we focus on the adsorption and ordering of the TPPS4-based J-aggregates on silicon and gold as well as on self-assembled monolayer (SAM) surfaces. The SAMs used for the experiments were based on the chemisorption of thiol containing compounds onto gold. Long ω-substituted alkanethiols are spontaneously assembled on gold to form highly ordered and densely packed layers with controllable chemical and physical properties. TPPS4 J-aggregates were dispersed on SAM surfaces, and on plain gold and silicon substrates for comparison. The dimensions of aggregates, measured by means of atomic force microscopy, varied depending on the type of substrate. Long stripe-like aggregates were flattened on the substrate surface, and the height and width of aggregates highly correlated with the polarity of surface groups. For example, the J-aggregates were narrower on hydrophobic substrates (with non-polar groups) and wider on hydrophilic substrates (with polar groups). These observations support the hypothesis, that TPPS4 forms .soft. cylindrical aggregates, that appear flattened on the substrate.

scholarly journals Structural characterization of gephyrin by AFM and SAXS reveals a mixture of compact and extended states

2013 ◽  
Vol 69 (10) ◽  
pp. 2050-2060 ◽  
Author(s):  
Bodo Sander ◽  
Giancarlo Tria ◽  
Alexander V. Shkumatov ◽  
Eun-Young Kim ◽  
J. Günter Grossmann ◽  
...  
Keyword(s):  
Conformational Dynamics ◽  
Cd Spectroscopy ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Extended States ◽  
High Degree

Gephyrin is a trimeric protein involved in the final steps of molybdenum-cofactor (Moco) biosynthesis and in the clustering of inhibitory glycine and GABAAreceptors at postsynaptic specializations. Each protomer consists of stably folded domains (referred to as the G and E domains) located at either terminus and connected by a proteolytically sensitive linker of ∼150 residues. Both terminal domains can oligomerize in their isolated forms; however, in the context of the full-length protein only the G-domain trimer is permanently present, whereas E-domain dimerization is prevented. Atomic force microscopy (AFM) and small-angle X-ray scattering (SAXS) reveal a high degree of flexibility in the structure of gephyrin. The results imply an equilibrium between compact and extended conformational states in solution, with a preference for compact states. CD spectroscopy suggests that a partial compaction is achieved by interactions of the linker with the G and E domains. Taken together, the data provide a rationale for the role of the linker in the overall structure and the conformational dynamics of gephyrin.

Ge/Si(100) Island and Wetting Layer Composition

2002 ◽  
Vol 749 ◽  
Author(s):  
Yangting Zhang ◽  
Jeff Drucker
Keyword(s):  
Rutherford Backscattering Spectrometry ◽  
Water Soluble ◽  
Wetting Layer ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After ◽  
Substrate Temperatures ◽  
Water Etching ◽  
Layer Composition

ABSTRATCTEtching water soluble Ge-oxides was used to investigate Si interdiffusion into epitaxial Ge / Si(100) samples. The Ge coverage, θGe, was measured using Rutherford backscattering spectrometry (RBS) before and after water etching of samples grown at substrate temperatures between 400 °C and 650 °C. θGewas correlated with sample morphology determined using atomic force microscopy (AFM). The local Ge concentration was qualitatively assessed using energy dispersive x-ray (EDX) analysis. For samples grown at T=400 °C, water completely dissolves the islands and no Ge is detected by RBS. For samples grown at T=600 and 650 °C, AFM detects no change in the surface morphology and RBS indicates that θGedecreases by about 3 monolayers (ML). These results suggest that for growth at T=400 °C, both the islands and wetting layer are relatively pure Ge while for growth at T≥600 °C, the wetting layer is Ge rich compare to the SiGe alloy islands. EDX confirms this conclusion detecting no Ge signal between islands for etched samples grown at T≥600 °C. Our results suggest that for growth at T≥600 °C, Si interdiffusion into islands is through the region underneath the islands instead of from the wetting layer.

Sign in / Sign up

Export Citation Format

Share Document