scholarly journals Preparation of Nafion/Polycation Layer-by-Layer Films for Adsorption and Release of Insulin

Polymers ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 812 ◽  
Author(s):  
Kentaro Yoshida ◽  
Katsuhiko Sato ◽  
Tetsuya Ono ◽  
Takenori Dairaku ◽  
Yoshitomo Kashiwagi
Keyword(s):  
Quartz Crystal ◽  
Fluorescence Emission ◽  
Layer By Layer ◽  
Ph Change ◽  
Mild Conditions ◽  
Atomic Force ◽  
Insulin Solution ◽  
Lbl Films ◽  
Uv Visible ◽  
Allylamine Hydrochloride

Thin films were prepared using layer-by-layer (LbL) deposition of Nafion (NAF) and polycations such as poly(allylamine hydrochloride) (PAH), poly(ethyleneimine) (PEI), and poly(diallydimethylammonium chloride) (PDDA). Insulin was then adsorbed on the NAF-polycation LbL films by immersion in an insulin solution. The NAF-polycation LbL films were characterized using a quartz crystal microbalance and an atomic force microscope. The release of insulin from the LbL films was characterized using UV-visible adsorption spectroscopy and fluorescence emission spectroscopy. The greatest amount of insulin was adsorbed on the NAF-PAH LbL film. The amount of insulin adsorbed on the (NAF/PAH)5NAF LbL films by immersion in a 1 mg mL−1 insulin solution at pH 7.4 was 61.8 µg cm−2. The amount of insulin released from the LbL films was higher when immersed in insulin solutions at pH 2.0 and pH 9.0 than at pH 7.4. Therefore, NAF-polycations could be employed as insulin delivery LbL films under mild conditions and as an insulin release control system according to pH change.

scholarly journals Fabrication and Characterization of Antibacterial-active Multilayer Films Based on Keggin Polyoxometalates and Methylene Blue

2010 ◽  
Vol 65 (2) ◽  
pp. 140-146 ◽  
Author(s):  
Dan Chen ◽  
Jun Peng ◽  
Haijun Pang ◽  
Pengpeng Zhang ◽  
Yuan Chen ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Self Assembly ◽  
Multilayer Films ◽  
Photoelectron Spectra ◽  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Assembly Technique ◽  
Lbl Films ◽  
Cv Measurements

Two kinds of multilayer films based on Keggin polyoxometalates α-[SiW12O40]4−/α- [PMo12O40]3− and methylene blue have been prepared via the layer-by-layer (LBL) self-assembly technique. The multilayer films were characterized by UV/Vis spectra, atomic force microscopy (AFM) and X-ray photoelectron spectra (XPS). The cyclic voltammetry (CV) measurements have demonstrated that the electrochemical properties of POMs are maintained in the LBL films. The antibacterial activity of the LBL films has also been investigated, which shows a distinct antibacterial effect against Escherichia coli.

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.

scholarly journals Tuning the Surface Properties of Poly(Allylamine Hydrochloride)-Based Multilayer Films

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2361
Author(s):  
Justyna Ciejka ◽  
Michal Grzybala ◽  
Arkadiusz Gut ◽  
Michal Szuwarzynski ◽  
Krzysztof Pyrc ◽  
...  
Keyword(s):  
Layer By Layer ◽  
Force Microscopy ◽  
Atomic Force ◽  
Micellar Aggregates ◽  
Afm Imaging ◽  
Physicochemical Features ◽  
Topmost Layer ◽  
Allylamine Hydrochloride ◽  
Proper Modification ◽  
Oppositely Charged

The layer-by-layer (LbL) method of polyelectrolyte multilayer (PEM) fabrication is extremely versatile. It allows using a pair of any oppositely charged polyelectrolytes. Nevertheless, it may be difficult to ascribe a particular physicochemical property of the resulting PEM to a structural or chemical feature of a single component. A solution to this problem is based on the application of a polycation and a polyanion obtained by proper modification of the same parent polymer. Polyelectrolyte multilayers (PEMs) were prepared using the LbL technique from hydrophilic and amphiphilic derivatives of poly(allylamine hydrochloride) (PAH). PAH derivatives were obtained by the substitution of amine groups in PAH with sulfonate, ammonium, and hydrophobic groups. The PEMs were stable in 1 M NaCl and showed three different modes of thickness growth: exponential, mixed exponential-linear, and linear. Their surfaces ranged from very hydrophilic to hydrophobic. Root mean square (RMS) roughness was very variable and depended on the PEM composition, sample environment (dry, wet), and the polymer constituting the topmost layer. Atomic force microscopy (AFM) imaging of the surfaces showed very different morphologies of PEMs, including very smooth, porous, and structured PEMs with micellar aggregates. Thus, by proper choice of PAH derivatives, surfaces with different physicochemical features (growth type, thickness, charge, wettability, roughness, surface morphology) were obtained.

MOLECULAR SELF-ASSEMBLY OF CHICAGO SKY BLUE ONTO SOLID SUBSTRATE

2011 ◽  
Vol 25 (14) ◽  
pp. 1905-1914 ◽  
Author(s):  
MD. N. ISLAM ◽  
D. DEY ◽  
D. BHATTACHARJEE ◽  
SYED ARSHAD HUSSAIN
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Self Assembly ◽  
Spectroscopic Studies ◽  
Solid Substrate ◽  
Organic Dye ◽  
Layer By Layer ◽  
Lbl Films ◽  
Allylamine Hydrochloride ◽  
Scanning Electron

Self-assembled films of organic dye Chicago Sky Blue 6B (CSB) have been fabricated onto solid substrate by electrostatic alternate adsorption of polycation ploy(allylamine hydrochloride) (PAH) and CSB. UV–Vis absorption spectroscopic studies reveal the successful incorporation of CSB molecules into Layer-by-Layer (LbL) films and consequent formation of aggregates. This view is supported by FTIR spectroscopic studies. Scanning electron microscope picture confirms the formation of nanocrystalline aggregates in the LbL films. About 15 min is required to complete the electrostatic interaction between PAH and CSB molecules in one bilayer LbL film.

Antimicrobial Activity of Silver Nanoparticles Synthesized by Streptomyces Species JF714876

2012 ◽  
Vol 5 (1) ◽  
pp. 1638-1642 ◽  
Author(s):  
Vidyasagar G M ◽  
Shankaravva B ◽  
R Begum ◽  
Imrose ◽  
Sagar R ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Human Beings ◽  
Streptomyces Species ◽  
Force Microscopy ◽  
E Coli ◽  
Extracellular Synthesis ◽  
Atomic Force ◽  
Uv Visible

Microorganisms like fungi, actinomycetes and bacteria are considered nanofactories and are helpful in the production of nanoparticles useful in the welfare of human beings. In the present study, we investigated the production of silver nanoparticles from Streptomyces species JF714876. Extracellular synthesis of silver nanoparticles by Streptomyces species was carried out using two different media. Silver nanoparticles were examined using UV-visible, IR and atomic force microscopy. The size of silver nanoparticles was in the range of 80-100 nm. Antimicrobial activity of silver nanoparticle against bacteria such as E. coli, S. aureus, and dermatophytes like T. rubrum and T. tonsurans was determined. Thus, this study suggests that the Streptomyces sp. JF741876 can produce silver ions that can be used as an antimicrobial substance.

Selective Hydrogen Bonding Controls Temperature Response of Layer-by-Layer Upper Critical Solution Temperature Micellar Assemblies

Soft Matter ◽  
2021 ◽  
Author(s):  
Aliaksei Aliakseyeu ◽  
Victoria Albright ◽  
Danielle Yarbrough ◽  
Samantha Hernandez ◽  
Qing Zhou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Methacrylic Acid ◽  
Temperature Response ◽  
Solution Temperature ◽  
Layer By Layer ◽  
Critical Solution Temperature ◽  
Hydrogen Bonding Interactions ◽  
Upper Critical Solution Temperature ◽  
Lbl Films

This work establishes a correlation between the selectivity of hydrogen-bonding interactions and the functionality of micelle-containing layer-by-layer (LbL) assemblies. Specifically, we explore LbL films formed by assembly of poly(methacrylic acid)...

scholarly journals Thermally Stimulated Desorption Optical Fiber-Based Interrogation System: An Analysis of Graphene Oxide Layers’ Stability

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 70
Author(s):  
Maria Raposo ◽  
Carlota Xavier ◽  
Catarina Monteiro ◽  
Susana Silva ◽  
Orlando Frazão ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Layer By Layer ◽  
Film Stability ◽  
A Value ◽  
Device Reliability ◽  
Sensor Devices ◽  
Lbl Films ◽  
The Stability

Thin graphene oxide (GO) film layers are being widely used as sensing layers in different types of electrical and optical sensor devices. GO layers are particularly popular because of their tuned interface reflectivity. The stability of GO layers is fundamental for sensor device reliability, particularly in complex aqueous environments such as wastewater. In this work, the stability of GO layers in layer-by-layer (LbL) films of polyethyleneimine (PEI) and GO was investigated. The results led to the following conclusions: PEI/GO films grow linearly with the number of bilayers as long as the adsorption time is kept constant; the adsorption kinetics of a GO layer follow the behavior of the adsorption of polyelectrolytes; and the interaction associated with the growth of these films is of the ionic type since the desorption activation energy has a value of 119 ± 17 kJ/mol. Therefore, it is possible to conclude that PEI/GO films are suitable for application in optical fiber sensor devices; most importantly, an optical fiber-based interrogation setup can easily be adapted to investigate in situ desorption via a thermally stimulated process. In addition, it is possible to draw inferences about film stability in solution in a fast, reliable way when compared with the traditional ones.

scholarly journals The Effect of Film Thickness and Content on Film Formation from PS/ Nanocomposites Prepared by Dip-Coating Method

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
M. Selin Sunay ◽  
Onder Pekcan ◽  
Saziye Ugur
Keyword(s):  
Film Thickness ◽  
Elevated Temperatures ◽  
Film Formation ◽  
Fluorescence Emission ◽  
Dip Coating ◽  
Atomic Force ◽  
Annealing Step ◽  
Coating Method ◽  
Fluorescence Emission Intensity ◽  
Dip Coating Method

Steady-state fluorescence (SSF) technique in conjunction with UV-visible (UVV) technique and atomic force microscope (AFM) was used for studying film formation from TiO2covered nanosized polystyrene (PS) latex particles (320 nm). The effects of film thickness and TiO2content on the film formation and structure properties of PS/TiO2composites were studied. For this purpose, two different sets of PS films with thicknesses of 5 and 20 μm were prepared from pyrene-(P-) labeled PS particles and covered with various layers of TiO2using dip-coating method. These films were then annealed at elevated temperatures above glass transition temperature () of PS in the range of 100–280°C. Fluorescence emission intensity, from P and transmitted light intensity, were measured after each annealing step to monitor the stages of film formation. The results showed that film formation from PS latexes occurs on the top surface of PS/TiO2composites and thus developed independent of TiO2content for both film sets. But the surface morphology of the films was found to vary with both TiO2content and film thickness. After removal of PS, thin films provide a quite ordered porous structure while thick films showed nonporous structure.

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