scholarly journals Photoresponsive Wettability in Monolayer Films from Sinapinic Acid

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Cleverson A. S. Moura ◽  
Douglas J. C. Gomes ◽  
Nara C. de Souza ◽  
Josmary R. Silva
Keyword(s):  
Uv Irradiation ◽  
Self Assembly ◽  
Irradiation Time ◽  
Morphological Structure ◽  
Sinapinic Acid ◽  
Layer By Layer ◽  
Monolayer Films ◽  
Wetting Contact Angle ◽  
Assembly Technique ◽  
Contact Angle Analysis

Sinapinic acid is an interesting material because it is both antioxidant and antibacterial agent. In addition, when illuminated with ultraviolet light, it can exhibit the so-called photodimerization process. In this paper, we report on the investigation of monolayer films from 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid, SinA) deposited onto poly(allylamine hydrochloride), PAH, films. SinA monolayers were prepared by using the layer-by-layer (LbL) self-assembly technique. Adsorption kinetics curves were well fitted by a biexponential function suggesting that the adsorption process is determined by two mechanisms: nucleation and growth of aggregates. By using wetting contact angle analysis, we have found that SinA monolayers exhibit photoresponsive wettability under UV irradiation (365 nm); that is, wettability decreases with increasing UV irradiation time. The photoresponse of wettability was attributed to photodimerization process. This hypothesis was supported by the dependence of surface morphological structure and absorption on UV irradiation time. The mechanism found in the well-known transcinnamic acid crystals is used to explain the photodimerization process in SinA monolayers.

Bioactivity of L-b-L Self-Assembly TiO2 Hollow Spheres by UV Irradiation Enhanced

2011 ◽  
Vol 328-330 ◽  
pp. 1495-1498
Author(s):  
Fan Xiao ◽  
Wei Li ◽  
Fei Gao ◽  
Zhi Xian Zhang
Keyword(s):  
Simulated Body Fluid ◽  
Uv Irradiation ◽  
Self Assembly ◽  
Body Fluid ◽  
Irradiation Time ◽  
Hollow Spheres ◽  
Layer By Layer ◽  
Assembly Technology ◽  
Hydrolysis Of ◽  
Better Than

Using nano-TiO2 particles obtained by hydrolysis of titanium oxysulfate (TiOSO4) as the precursor, and polystyrene (PS) spheres as the template, TiO2 hollow spheres were successfully deposited on CPTi substrates through layer-by-layer self-assembly technology. After ultraviolet light (UV) irradiation, the TiO2 coatings were soaked in simulated body fluid (SBF) to explore their bioactivities. The effects of UV irradiation time and UV irradiation media on the bioactivities of nano TiO2 coatings were investigated. The results show that bone-like apatite can be formed on the surface of nano TiO2 coating irradiated by UV, and this reveals that the irradiated coating has good bioactivity. The amount of apatite formed on the surface of the coating increases with the increase of UV irradiation time. UV-irradiated media also influence the bioactivity of the coating. The bioactivities of nano TiO2 coatings irradiated in air and SBF are better than that in water.

Multilayer composite beads constructed via layer-by-layer self-assembly for lysozyme controlled release

RSC Advances ◽  
2014 ◽  
Vol 4 (46) ◽  
pp. 24369-24376 ◽  
Author(s):  
Jiemin Zhao ◽  
Xiaoping Wang ◽  
Yanshen Kuang ◽  
Yufeng Zhang ◽  
Xiaowen Shi ◽  
...  
Keyword(s):  
Controlled Release ◽  
Self Assembly ◽  
Cross Linking ◽  
Layer By Layer ◽  
Multilayer Composite ◽  
Composite Beads ◽  
Assembly Technique ◽  
Positively Charged

Alginate (ALG)–lysozyme (LZ) beads were fabricated by a cross-linking process. Negatively charged ALG and positively charged LZ were alternately deposited on the positively charged ALG–LZ beads via a layer-by-layer (LBL) self-assembly technique.

scholarly journals Fabrication and in vitro evaluation of stable collagen/hyaluronic acid biomimetic multilayer on titanium coatings

2013 ◽  
Vol 10 (84) ◽  
pp. 20130070 ◽  
Author(s):  
Haiyong Ao ◽  
Youtao Xie ◽  
Honglue Tan ◽  
Shengbing Yang ◽  
Kai Li ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Human Mesenchymal Stem Cells ◽  
Biological Properties ◽  
Covalent Immobilization ◽  
Layer By Layer ◽  
Titanium Coating ◽  
Assembly Technique

Layer-by-layer (LBL) self-assembly technique has been proved to be a highly effective method to immobilize the main components of the extracellular matrix such as collagen and hyaluronic acid on titanium-based implants and form a polyelectrolyte multilayer (PEM) film by electrostatic interaction. However, the formed PEM film is unstable in the physiological environment and affects the long-time effectiveness of PEM film. In this study, a modified LBL technology has been developed to fabricate a stable collagen/hyaluronic acid (Col/HA) PEM film on titanium coating (TC) by introducing covalent immobilization. Scanning electron microscopy, diffuse reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to characterize the PEM film. Results of Sirius red staining demonstrated that the chemical stability of PEM film was greatly improved by covalent cross-linking. Cell culture assays further illustrated that the functions of human mesenchymal stem cells, such as attachment, spreading, proliferation and differentiation, were obviously enhanced by the covalently immobilized Col/HA PEM on TCs compared with the absorbed Col/HA PEM. The improved stability and biological properties of the Col/HA PEM covalently immobilized TC may be beneficial to the early osseointegration of the implants.

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.

Layer-by-layer self-assembled laminin/fucoidan films: towards better hemocompatibility and endothelialization

RSC Advances ◽  
2016 ◽  
Vol 6 (61) ◽  
pp. 56048-56055 ◽  
Author(s):  
Yan Wang ◽  
Changrong Ye ◽  
Hong Su ◽  
Juan Wang ◽  
Yanan Wang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Multilayer Film ◽  
Layer By Layer ◽  
Assembly Technique ◽  
Self Assembled

The laminin/fucoidan multilayer film is prepared on glass via layer-by-layer self-assembly technique and monitored the assembled process by QCM-D. This film can inhibit platelets adhesion and improve ECs and EPCs adhesion.

Preparation and Characterization of Nano-Films Materials

2011 ◽  
Vol 492 ◽  
pp. 160-163
Author(s):  
Cai Xia Li ◽  
Qing Lv ◽  
Jie Song ◽  
Dan Yu Jiang ◽  
Qiang Li
Keyword(s):  
Self Assembly ◽  
Chemical Properties ◽  
Layered Compounds ◽  
Insertion Reaction ◽  
Layer By Layer ◽  
Vis Spectroscopy ◽  
Assembly Technique ◽  
Assembly Technology ◽  
Physical And Chemical

Nano-sheets are two-dimensional sheet materials exfoliated from the inorganic layered compounds by various physical and chemical methods. Their unique characteristics insertion reaction and excellent physical and chemical properties have attracted more and more researchers' widespread interests. Selecting quartz glass as the substrate, using layer by layer self-assembly technology, different nano-films materials are prepared. UV/Vis spectroscopy confirmed nano-films materials have been successfully assembled using LBL self-assembly technique. Raman spectrum are mainly used to analyze and characterize the structure of nano-films materials.

UV-Enhanced Bioactivity of PS/TiO2 Coating Prepared by Layer-by-Layer Self-Assembly Method

2010 ◽  
Vol 434-435 ◽  
pp. 579-581
Author(s):  
Zhi Xian Zhang ◽  
Fan Xiao ◽  
Fei Gao
Keyword(s):  
Uv Irradiation ◽  
Ultraviolet Irradiation ◽  
Self Assembly ◽  
Raw Material ◽  
Layer By Layer ◽  
Titanium Coating ◽  
Water Contact ◽  
Oh Groups ◽  
Assembly Method ◽  
Assembly Technology

The TiO2 nanopowder was prepared with TiOSO4 as raw material at low temperature by hydrolysis method, and microspheres coated polyethylene and TiO2 were then fabricated on titanium by layer-by-layer self-assembly technology. Using ultraviolet irradiation of titanium coating in distilled water for some time, titanium with enhanced bioactivity was achieved when immersed in simulated body fluid (SBF). The morphology, size and crystal shape before and after ultraviolet irradiation were characterized by scanning electron microcopy (SEM) and X-ray diffraction (XRD). UV irradiation of titanium results in the conversion of Ti4+ to Ti3+ and the generation of oxygen vacancies, which could react with the absorbed water to form basic Ti–OH groups. Compared with the coating non-UV irradiation, the UV-irradiated coatings do not present any obvious differences in morphology, surface roughness, grain size and phase component; however, they have more abundant basic Ti–OH groups thus the water contact angle decreases greatly so the surface become much more hydrophilic.

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