Ultrathin Films of Oriented Bacteriorhodopsin: Nanostructured Films for Investigating the Primary Photoevent in Vision Processes

2001 ◽  
Vol 679 ◽  
Author(s):  
Rigoberto C. Advincula ◽  
Mi-kyoung Park
Keyword(s):  
Ultrathin Films ◽  
Supramolecular Assembly ◽  
Solid Substrate ◽  
Film Structure ◽  
Glass Electrode ◽  
Layer By Layer ◽  
Ph Change ◽  
Force Microscopy ◽  
Atomic Force ◽  
Substrate Surfaces

ABSTRACTIn this work, a protocol for investigating Bacteriorhodopsin (BR) biomimetic systems as ultrathin films is presented. BR is one of the most well studied proteins important for investigating the primary photo-event in vision processes. The use of macromolecular assembly approaches for deposition onto solid support substrates, e.g. SiOx, gold- or ITO-coated glass (electrode) provide advantages in that surface sensitive measurements can be used to correlate photocurrent generation, photoelectric response, pH change, chromophore behavior, etc. with protein orientation at interfaces. Membrane and protein morphology were correlated to measurements using surface sensitive techniques, such as atomic force microscopy (AFM), ellipsometry, quartz crystal microbalance (QCM), etc. on solid-substrate systems. These studies can lead to applications in optobioelectronic devices (biosensors) including patterning in transducer array configurations, where the film structure is important. Hybrid films are possible with supramolecular assembly approaches, e.g. adsorption of membrane with lipidbilayers. We report our initial results on highly ordered and oriented BR protein arrays of controlled thickness, layer order, and orientation. This was done primarily using the alternate polyelectrolyte deposition (APD) or layer-by-layer (LbL) approach to functionalize substrate surfaces.

Self-assembly layer-by-layer fabrication using porphyrin dye anion and polycation

2009 ◽  
Vol 13 (07) ◽  
pp. 774-778 ◽  
Author(s):  
Byung-Soon Kim ◽  
Young-A Son
Keyword(s):  
Ultrathin Films ◽  
Self Assembly ◽  
Film Surface ◽  
Layer By Layer ◽  
Preparation Technique ◽  
Force Microscopy ◽  
Atomic Force ◽  
Diallyldimethylammonium Chloride ◽  
Afm Analysis ◽  
Progressive Growth

In this study, self-assembled alternating film using poly(diallyldimethylammonium chloride) (PDDAC) and meso-tetrakis(4-carboxyphenyl)porphyrin (MTCP) was prepared as a multilayer deposition on glass substrate. This preparation technique for dye deposition may provide new feasibilities to achieve the manufacture of ultrathin films for nanotechnology application. The deposition films were characterized by UV-vis spectrophotometer and Atomic Force Microscopy (AFM) analysis. The results of UV-vis spectra showed that the absorbance characteristic of the multilayer films linearly increased with an increased number of PDDAC and MTCP bilayers. AFM analysis showed the film surface was relatively uniform and the progressive growth of layers was determined.

Nanostructured Ultrathin Films of Silicate Clay and Polyelectrolytes: Deposition Parameters and Mechanical Properties by Nanoindentation

2001 ◽  
Vol 697 ◽  
Author(s):  
Xiaowu Fan ◽  
Rigoberto C. Advincula
Keyword(s):  
Mechanical Properties ◽  
Ultrathin Films ◽  
Structural Information ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Clay Platelet ◽  
Force Microscopy ◽  
Atomic Force ◽  
Deposition Parameters ◽  
Relationship Of

AbstractRecently, we have investigated the electrostatic layer-by-layer (ELBL) deposition of polycation and clay platelet ultrathin films. We have investigated the properties of these films using techniques such as ellipsometry, X-ray diffraction and atomic force microscopy (AFM). In this work, we report our results regarding the formation of this type of hybrid ultrathin films focusing on their mechanical properties as probed by nanoindentation experiments. Structural information such as film thickness, platelet coverage, surface morphology, roughness, etc., is important parameters for their potential use as coatings. We have investigated the relationship of several of these parameters with their mechanical hardness and modulus properties as a function of indentor probe depth in nanoindentation experiments. The ultrathin films have remarkable mechanical properties very different from most polymer ultrathin films.

scholarly journals Characterization of Strong and Crystalline Polyvinyl Alcohol/Montmorillonite Films Prepared by Layer-by-Layer Deposition Method

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
S. Gaidukov ◽  
I. Danilenko ◽  
G. Gaidukova
Keyword(s):  
Polyvinyl Alcohol ◽  
Thermal Studies ◽  
High Strength ◽  
Film Structure ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Layer Deposition

The preparation of a high-strength and highly crystalline nanocomposite with a layered structure by the use of layer-by-layer deposition (LbL) method from polyvinyl alcohol (PVOH) and montmorillonite (MMT) platelets is reported. The crystallinity and interactions between the components were studied by the use of Fourier transform infrared spectroscopy (FT-IR), wide angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The nanocomposite film structure was investigated by the use of scanning electron microscope (SEM) and atomic force microscopy (AFM). The stiffness of the LbL PVOH/MMT film was significantly higher compared to pure PVOH and conventional PVOH/MMT nanocomposite. The structural and thermal studies on thin PVOH/MMT films indicated the enhanced crystallinity of the polymer.

Lateral Size of Self-Patterned Nanostructures Controlled by Multi-Step Deposition

2005 ◽  
Vol 106 ◽  
pp. 117-122 ◽  
Author(s):  
Izabela Szafraniak ◽  
Dietrich Hesse ◽  
Marin Alexe
Keyword(s):  
Electron Microscopy ◽  
Ultrathin Films ◽  
Lateral Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Non Volatile Memory ◽  
Ferroelectric Capacitors ◽  
Scanning Electron

Self-patterning presents an appealing alternative to lithography for the production of arrays of nanoscale ferroelectric capacitors for use in high density non-volatile memory devices. Recently a self-patterning method, based on the use of the instability of ultrathin films during hightemperature treatments, was used to fabricate nanosized ferroelectrics. This paper reports the use of the method for the preparation of PZT nanoislands on different single crystalline substrates - SrTiO3, MgO and LaAlO3. Moreover, a multi-step deposition procedure in order to control lateral the dimension of the crystals was introduced. The nanostructures obtained were studied by atomic force microscopy, scanning electron microscopy and X-ray diffraction.

Conducting Polymer nanoComposites (CPC): Nanocharacterisation of layer by layer sprayed PMMA-CNT vapour sensors by Atomic force Microscopy in current Sensing Mode (CS-AFM)

2008 ◽  
Vol 1143 ◽  
Author(s):  
Bijandra Kumar ◽  
Mickaël Castro ◽  
Jianbo Lu ◽  
Jean-François Feller
Keyword(s):  
Atomic Force Microscopy ◽  
Spray Deposition ◽  
Dynamic Mode ◽  
Layer By Layer ◽  
Initial State ◽  
Contact Mode ◽  
Current Sensing ◽  
Multi Wall Carbon Nanotubes ◽  
Force Microscopy ◽  
Atomic Force

ABSTRACTOrganic vapour sensors based on poly (methylmethacrylate)-multi-wall carbon nanotubes (PMMA-CNT) conductive polymer nanocomposite (CPC) were developed via layer by layer technique by spray deposition. CPC Sensors were exposed to three different classes of solvents (chloroform, methanol and water) and their chemo-electrical properties were followed as a function of CNTcontent in dynamic mode. Detection time was found to be shorter than that necessary for full recovery of initial state. CNT real three dimensional network has been visualized by Atomic force microscopy in a field assisted intermittent contact mode. More interestingly real conductive network system and electrical ability of CPC have been explored by current-sensing atomic force microscopy (CS-AFM). Realistic effect of voltage on electrical conductivity has been found linear.

A Cell's Perspective of its Culture Surface

2007 ◽  
Vol 1060 ◽  
Author(s):  
Ruchirej Yongsunthon ◽  
David E. Baker ◽  
Wendy A. Baker ◽  
Theresa Chang ◽  
Wanda J. Walczak ◽  
...  
Keyword(s):  
Culture Media ◽  
Preliminary Investigation ◽  
Surface Proteins ◽  
Force Microscopy ◽  
Driving Mechanisms ◽  
Atomic Force ◽  
Debye Shielding ◽  
Culture Surface ◽  
Substrate Surfaces ◽  
Functionalized Tips

ABSTRACTAtomic Force Microscopy (AFM) was employed to probe the internal structure of living HepG2/C3A cells grown on various commercially-available substrates. In order to understand the driving mechanisms behind the different cell morphologies, the surface properties of these substrates was characterized with AFM and related techniques. The roughness of a 10μm×10μm region of a series of substrates was determined and found to be independent of both coating and culture media, with the exception of thick hydrogel-like coatings. Probing with functionalized tips could not distinguish relative degrees of hydrophobicity under cell culture media, presumably because Debye shielding masks the substrate surfaces. Force spectroscopy was performed on the surfaces to determine exposed surface proteins/polymers intrinsic to the substrate and adsorbed from culture media. Preliminary investigation of cell-mediated substrate reconstruction suggests that the cells secrete large (1000kDa) polymeric molecules at the substrate interface.

scholarly journals Layer by Layer Antimicrobial Coatings Based on Nafion, Lysozyme, and Chitosan

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1563 ◽  
Author(s):  
Ella N. Gibbons ◽  
Charis Winder ◽  
Elliot Barron ◽  
Diogo Fernandes ◽  
Marta J. Krysmann ◽  
...  
Keyword(s):  
Surface Characteristics ◽  
Building Blocks ◽  
Layer By Layer ◽  
Exclusion Zone ◽  
Antimicrobial Coatings ◽  
Force Microscopy ◽  
New Family ◽  
Atomic Force ◽  
Multilayer Assemblies ◽  
And Staphylococcus Aureus

The study focuses on the development of a new family of layer-by-layer coatings comprising Nafion, lysozyme and chitosan to address challenges related to microbial contamination. Circular dichroism was employed to gain insights on the interactions of the building blocks at the molecular level. Quartz crystal microbalance tests were used to monitor in real time the build-up of multilayer coatings, while atomic force microscopy, contact angle and surface zeta potential measurements were performed to assess the surface characteristics of the multilayer assemblies. Remarkably, the nanocoated surfaces show almost 100% reduction in the population of both Escherichia coli and Staphylococcus aureus. The study suggests that Nafion based synergistic platforms can offer an effective line of defence against bacteria, facilitating antimicrobial mechanisms that go beyond the concept of exclusion zone.

scholarly journals Probing surface interactions of underwater oleophobic polyelectrolyte multilayers

2020 ◽  
Author(s):  
Kai Li ◽  
Wei Wang ◽  
Zhi-Peng Yu ◽  
Hang Jin ◽  
Yun-Tong Ge ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Interaction Mechanism ◽  
Polyelectrolyte Multilayers ◽  
Layer By Layer ◽  
Surface Wetting ◽  
Force Microscopy ◽  
Atomic Force ◽  
Layer Deposition ◽  
Nacl Concentration ◽  
Force Curves

Abstract In the present work, the interaction mechanism of specific polyelectrolyte multilayers (PEMs), fabricated by layer-by-layer deposition of polydiallyldimethylammonium chloride (PDDA) and poly(sodium 4-styrenesulfonate) (PSS), is studied using atomic force microscopy. The underwater oil-repellency of PSS-capped PEMs was further explored by measuring the interaction forces between tetradecane droplets and PEMs-coated silica substrates under various salinities. The force curves were analyzed following the Stokes–Reynolds–Young–Laplace theoretical model. Desirable consistency was achieved between the experimental and theoretical calculations at low NaCl concentrations (0.1 mM and 1 mM); however, underestimation of the attractive force was found as the NaCl concentration increases to moderate (10 mM) and high (100 mM) levels. Discrepancy analyses and incorporated features toward a reduced surface charge density were considered based on the previous findings of the orientation of anionic benzenesulfonate moieties (Liu et al. in Angew Chem Int Ed 54(16):4851–4856, 2015. https://doi.org/10.1002/anie.201411992). Short-range steric hindrance interactions were further introduced to simulate “brush” effect stemming from nanoscale surface roughness. It is demonstrated in our work that the PSS-capped PEMs remains a stable underwater lipophobicity against high salinity, which renders it potential application in surface wetting modification and anti-fouling.

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