Nanomechanical properties of ordered phthalocyanine Langmuir–Blodgett layers

2004 ◽  
Vol 19 (5) ◽  
pp. 1461-1470 ◽  
Author(s):  
Tammy Oshiro ◽  
Arnie Backstrom ◽  
Ann-Marie Cumberlidge ◽  
K.W. Hipps ◽  
Ursula Mazur ◽  
...  
Keyword(s):  
Copper Phthalocyanine ◽  
Multilayer Structures ◽  
Monolayer Films ◽  
One Dimensional ◽  
Langmuir Blodgett ◽  
Nanomechanical Properties ◽  
Lb Film ◽  
Pressure Area ◽  
Additional Stability ◽  
Interlayer Structure

The mechanical properties of monolayer and multilayer structures of several symmetrically substituted alkoxy copper phthalocyanine, CuPc(OR)8, Langmuir–Blodgett (LB) films were evaluated. One-dimensional compliance of the monolayers was determined from the slopes of the surface pressure–area isotherms. Multilayers were examined using a SPM and a commercial nanoindentation system. The nanomechanical studies show a distinct relationship between the position and length of alkoxy substituents on the Pc macrocycle and the LB film elasticity and hardness. The phthalocyanine complexes with peripheral octabutoxy and octaoctyloxy substituents form stiff LB monolayers and multilayers. The nonperipheral alkoxy derivetized CuPc films were less stiff. For monolayer films, it appears that the extent of π-π interaction determines the strength of the film. In multilayers, significant additional stability can be imparted through interdigitation of long paraffinic chains which play a significant role in determining the interlayer structure of the LB layers.

Streptavidin-Phycoerythrin Conjugated Proteins Bound to Biotin on Langmuir-Blodgett Films of Biotinylated Lipid Monolayers

1990 ◽  
Vol 218 ◽  
Author(s):  
Lynne A. Samuelson ◽  
D. L. Kaplan ◽  
K. A. Marx ◽  
P. Miller ◽  
D. M. Galotti ◽  
...  
Keyword(s):  
Specific Binding ◽  
Lipid Monolayers ◽  
Interface Pressure ◽  
Monolayer Films ◽  
Protein Charge ◽  
Langmuir Blodgett ◽  
Surface Recognition ◽  
Langmuir Blodgett Films ◽  
Pressure Area ◽  
Structure Research

AbstractStudies involving the specific and non-specific surface recognition of biotin on biotinylated LB lipid monolayers by streptavidin and avidin conjugated phycoerythrin are presented. Both streptavidin and avidin conjugates were injected under the monolayer and found to preferentially adsorb to the biotinylated monolayers at the air-water interface. Pressure-area isotherms displayed a biotin-streptavidin/avidin complex dependent increase in surface pressure at expanded areas indicating protein adsorption. The binding of protein was confirmed by transferring the monolayer films to solid supports and measuring the characteristic intense phycoerythrin fluorescence at 576 nm. The effect of protein charge, monolayer packing density and structure, and activation of the tetramer proteins towards specific and non-specific binding are discussed. These results suggest a novel and general methodology for the two-dimensional ordering of protein monolayers with potential bioelectronic, optical and protein structure research applications.

Biotinylated Polythiophene Copolymer – a Novel Electroactive Biomaterial Utilizing the Biotin-Streptavidin Interaction

1992 ◽  
Vol 292 ◽  
Author(s):  
Jeong-Ok Lim ◽  
Manjunath Kamath ◽  
Kenneth A. Marx ◽  
Sukant K. Tripathy ◽  
David L. Kaplan ◽  
...  
Keyword(s):  
Binding Sites ◽  
Solid Substrate ◽  
Emission Peak ◽  
One Dimensional ◽  
Langmuir Blodgett ◽  
Significant Area ◽  
Pressure Area ◽  
Biotin Binding ◽  
Monolayer Assembly ◽  
Area Expansion

AbstractA novel hierarchical biomaterial capable of incorporating any biotinylated biomolecule has been created. Our strategy is to biotinylate one-dimensional electroactive polymers and use a bridging streptavidin protein on Langmuir-Blodgett (LB) organized films. The following copolymeric system which enables functionalization of other molecules and formation of good monolayers was employed. Biotinylated poly(3-methanolthiophene-co-3-undecylthiophene) (B-PMUT) demonstrated a significantly better isotherm implying superior molecular packing compared to poly(3-methanolthiophene-co-3-undecylthiophene) (PMUT) on the LB airwater surface. The isotherm showed significant area expansion when streptavidin was injected below the B-PMUT monolayer in 0.1mM NaH2PO4/0.1 M NaCl buffer (pH 6.8) subphase. We then incorporated biotinylated phycoerythrin (B-PE) into this novel biomaterial by binding the unoccupied biotin binding sites on the bound streptavidin (4 sites total). The pressure-area isotherm of the protein injected monolayer showed area expansion. A characteristic fluorescent emission peak at 576nm was detected from the monolayer transferred onto a solid substrate. These observations demonstrated the function of B-PMUT in hierarchical monolayer assembly of molecules incorporating the biotin / streptavidin interaction.

scholarly journals Effect of Fe3O4 Nanoparticles on Mixed POPC/DPPC Monolayers at Air-Water Interface

Scanning ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Zhuangwei Xu ◽  
Changchun Hao ◽  
Bin Xie ◽  
Runguang Sun
Keyword(s):  
Targeted Drug Delivery ◽  
Compression Modulus ◽  
Repulsive Force ◽  
Polar Group ◽  
Attraction Force ◽  
Langmuir Blodgett ◽  
Lb Film ◽  
Atomic Force ◽  
Air Water Interface ◽  
Pressure Area

Fe3O4 nanoparticles (NPs) as a commonly used carrier in targeted drug delivery are widely used to carry drugs for the treatment of diseases. However, the mechanism of action of between Fe3O4 NPs and biological membranes is still unclear. Therefore, this article reports the influence of hydrophilic and hydrophobic Fe3O4 NPs on mixed 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) that were studied using the Langmuir-Blodgett (LB) film technique and an atomic force microscope (AFM). From surface pressure-area (π-A) isotherms, we have calculated the compression modulus. The results showed that hydrophobic Fe3O4 NPs enlarged the liquid-expanded (LE) and liquid-condensed (LC) phase of the mixed POPC/DPPC monolayers. The compressibility modulus of the mixed POPC/DPPC monolayer increases for hydrophilic Fe3O4 NPs, but the opposite happens for the hydrophobic Fe3O4 NPs. The adsorption of hydrophobic Fe3O4 NPs in mixed POPC/DPPC monolayers was much more than the hydrophilic Fe3O4 NPs. The interaction of hydrophilic Fe3O4 NPs with the head polar group of the mixed lipids increased the attraction force among the molecules, while the interaction of hydrophobic Fe3O4 NPs with the tail chain of the mixed lipids enhanced the repulsive force. The morphology of the monolayers was observed by AFM for validating the inferred results. This study is of great help for the application of Fe3O4 NPs in biological systems.

NO2 gas detection by Langmuir-Blodgett films of copper phthalocyanine multilayer structures

1997 ◽  
Vol 4 (3-4) ◽  
pp. 461-464 ◽  
Author(s):  
R. Rella ◽  
A. Serra ◽  
P. Siciliano ◽  
A. Tepore ◽  
L. Valli ◽  
...  
Keyword(s):  
Copper Phthalocyanine ◽  
Gas Detection ◽  
Multilayer Structures ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films

Metastability in Monolayer Films Transferred onto Solid Substrates by the Langmuir-Blodgett Method: IR Evidence for Transfer-Induced Phase Transitions

1994 ◽  
Vol 48 (10) ◽  
pp. 1196-1203 ◽  
Author(s):  
Fazale R. Rana ◽  
Suci Widayati ◽  
Brian W. Gregory ◽  
Richard A. Dluhy
Keyword(s):  
Fatty Acid ◽  
Conformational Changes ◽  
Structural Changes ◽  
High Surface ◽  
Solid Substrate ◽  
Water Interface ◽  
Monolayer Films ◽  
Langmuir Blodgett ◽  
Monomolecular Film ◽  
Air Water Interface

The rate at which a monomolecular film is deposited onto a solid substrate in the Langmuir-Blodgett process of preparing supported monolayer films influences the final structure of the transferred film. Attenuated total reflectance infrared spectroscopic studies of monolayers transferred to germanium substrates show that the speed at which the substrate is drawn through the air/water interface influences the final conformation in the hydrocarbon chains of amphiphilic film molecules. This transfer-induced effect is especially evident when the monolayer is transferred from the expanded region of surface-pressure-molecular-area isotherms at low surface pressures; the effect is minimized when the film molecules are transferred from condensed phases at high surface pressures. This phenomenon has been observed for both a fatty acid and a phospholipid, which suggests that these conformational changes may occur in a variety of hydrocarbon amphiphiles transferred from the air/water interface. This conformational ordering may be due to a kinetically limited phase transition taking place in the meniscus formed between the solid substrate and aqueous subphase. In addition, the results obtained for both the phospholipid and fatty acid suggest that the structure of the amphiphile may help determine the extent and nature of the transfer-speed-induced structural changes taking place in the monomolecular film.

PREPARATION AND CHARACTERIZATION OF ORGANIC THIN FILM OF STEARIC ACID/PYRAZOLINE NANOPARTICLES

2006 ◽  
Vol 05 (02n03) ◽  
pp. 199-205
Author(s):  
YOUNG SOO KANG ◽  
SUN WHA OH ◽  
JONG HWA SUH
Keyword(s):  
Stearic Acid ◽  
Organic Thin Films ◽  
Solid Substrate ◽  
Organic Thin Film ◽  
Blodgett Film ◽  
Optical Absorbance ◽  
Langmuir Blodgett ◽  
Pressure Area

The organic thin films of stearic acid/pyrazoline nanoparticles were prepared by transferring Langmuir monolayer of stearic acid/pyrazoline nanoparticle onto the solid substrate. The complex of stearic acid/pyrazoline nanoparticle was studied with pressure–area isotherm at the air/water interface and identified with linearly increasing optical absorbance around 370 nm by increasing the number of deposited layers. The in situ domain structure and molecular orientation of the complex were measured with BAM. The surface morphology of the Langmuir–Blodgett film was observed with AFM. The dispersion of pyrazoline nanoparticle in the film was studied with TEM.

Molecular Organization of Nonlinear Organic Films Laminated by Langmuir-Blodgett Method

2005 ◽  
Vol 492-493 ◽  
pp. 115-122 ◽  
Author(s):  
Saburo Uchida ◽  
Vijay T. Chitnis ◽  
Hideo Furuhashi ◽  
Toshio Yoshikawa ◽  
Akinori Maeda ◽  
...  
Keyword(s):  
Surface Pressure ◽  
Nonlinear Optical ◽  
Epitaxial Films ◽  
Operating Conditions ◽  
Molecular Organization ◽  
Optimum Operating ◽  
Monolayer Formation ◽  
Langmuir Blodgett ◽  
Molecular Arrangement ◽  
Pressure Area

In the 21st century, the optical computation is likely to be the basic technology for processing lots of information at high speed. The aim of the present research work is to develop optical logic gates or memory chips. For this purpose, we have examined the suitability of organic nonlinear optical dye material Vanadyl-phthalocyanine (VOPc). Large single crystals of this material have been fabricated by using Molecular Beam Epitaxy (MBE) technique. The epitaxial films were formed on the substrate under optimum operating conditions. However, the epitixial growth is observed only up to a limited thickness. Above this thickness, the films become non-epitaxial, which can be improved by annealing. The reformation of the epitaxial films has been confirmed. We have also reported the effects of the environment of high temperature on the multilayered tetra-tert-butyl-Vanadyl-phthalocyanine ((t-bu)4VOPc) films, formed by Langmuir-Blodgett (LB) method. The solvent used to dissolve ((t-bu)4VOPc) was 1,2-dichloroethane. The monolayer on the surface of the water was transferred to a glass substrate by the vertical dipping method. If the multilayered stack is too thick, the molecular arrangement of the film may get disturbed. The improvement in the molecular arrangement of the LB films was examined and confirmed by measuring it’s nonlinear optical susceptibility, using Maker Fringe Method. Monolayer formation on water surface depends on the surface pressure-area isotherm. If this monolayer formation is not perfect, multiplayer stacks cannot be formed. The molecular films were aligned almost perpendicular to the substrate, as estimated from the limiting molecular area of surface pressure-area isotherm. The molecular organization of the monolayer on the substrate and the molecular structure of the multilayered ((t-bu)4VOPc) films are discussed.

Nitrogen oxide gas sensor based on tetra-tertbutyl copper phthalocyanine Langmuir-Blodgett films†

1995 ◽  
Vol 78 (1) ◽  
pp. 129-133 ◽  
Author(s):  
A. V. NABOK ◽  
Z. I. KAZANTSEVA ◽  
N. V. LAVRIK ◽  
B. A. NESTERENKO
Keyword(s):  
Nitrogen Oxide ◽  
Gas Sensor ◽  
Copper Phthalocyanine ◽  
Langmuir Blodgett ◽  
Langmuir Blodgett Films

Intelligent Biomaterials Based on Langmuir-Blodgett Monolayer Films

1994 ◽  
pp. 395-412 ◽  
Author(s):  
K. A. Marx ◽  
L. A. Samuelson ◽  
M. Kamath ◽  
J. O. Lim ◽  
S. Sengupta ◽  
...  
Keyword(s):  
Monolayer Films ◽  
Langmuir Blodgett
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