scholarly journals Influence of Extracellular Mimicked Hierarchical Nano-Micro-Topography on the Bacteria/Abiotic Interface

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 828 ◽  
Author(s):  
Sílvia Ferreira ◽  
Ana P. Piedade
Keyword(s):  
Thin Films ◽  
Surface Chemistry ◽  
Resistant Bacteria ◽  
Bacterial Strains ◽  
Average Roughness ◽  
Topographic Features ◽  
Deposition Parameters ◽  
Topographical Cues ◽  
Antibacterial Surfaces ◽  
Micro Topography

The study of interfaces between engineered surfaces and prokaryotic cells is a subject whose actual relevance has been reinforced by the current outbreaks due to unknown viruses and antibiotic-resistant bacteria. Studies aiming at the development of antibacterial surfaces are based on two pillars: surface chemistry or topographical cues. This work reports the study of only the topographic aspect by the development of thin films of polyamide, which present attractive surface chemistry for bacterial adhesion. The same chemistry with only nano- or hierarchical nano- and micro-topography that mimics the extracellular matrix is obtained by sputter-depositing the thin films onto Si and polydimethylsiloxane (PDMS), respectively. The surface average roughness of the Si-modified surfaces was around 1 nm, while the hierarchical topography presented values from 750 to 1000 nm, with wavelengths and amplitudes ranging from 15–30 µm and 1–3 µm, respectively, depending on the deposition parameters. The surface topography, wettability, surface charge, and mechanical properties were determined and related to interface performance with two Gram+ and two Gram- bacterial strains. The overall results show that surfaces with only nano-topographic features present less density of bacteria, regardless of their cell wall composition or cell shape, if the appropriate surface chemistry is present.

Observations on the growth of YBa2Cu3O7-δ thin films on MgO by pulsed-laser ablation

1991 ◽  
Vol 49 ◽  
pp. 1068-1069
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Laser Ablation ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Laser Ablation Process ◽  
Deposition Parameters

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.

Phyto-fabrication of Iron Nanoparticles: Characterization and Antibacterial Capacity

2020 ◽  
Vol 16 ◽  
Author(s):  
Asma S. Algebaly ◽  
Afrah E. Mohammed ◽  
Mudawi M. Elobeid
Keyword(s):  
Electron Microscopy ◽  
Plant Extracts ◽  
Large Scale ◽  
Iron Nanoparticles ◽  
Ethanolic Extract ◽  
Green Technology ◽  
Resistant Bacteria ◽  
Scale Production ◽  
Bacterial Strains ◽  
Plant Sources

Introduction: Fabrication of iron nanoparticles (FeNPs) has recently gained a great concern for their varied applications in remediation technologies of the environment. Objective: The current study aimed to fabricate iron nanoparticles by green technology approach using different plant sources, Azadirachta indica leaf and Calligonum comosum root following two extraction methods. Methods: Currently, a mixture of FeCl2 and FeCl3 was used to react with the plant extracts which are considered as reducing and stabilizing agents for the generation of FeNPs in one step. Different techniques were used for FeNPs identification. Results: Immediately after mixing of the two reaction components, the color changed to dark brown as an indication of safe conversion of Fe ions to FeNPs, that later confirmed by zeta sizer, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). FeNPs fabricated by C. comosum showed smaller size when compared by those fabricated by A. indica. Using both plant sources, FeNPs fabricated by the aqueous extract had smaller size in relation to those fabricated by ethanolic extract. Furthermore, antibacterial ability against two bacterial strains was approved. Conclusion: The current results indicated that, at room temperature plant extracts fabricated Fe ion to Fe nanoparticles, suggesting its probable usage for large scale production as well as its suitability against bacteria. It could also be recommended for antibiotic resistant bacteria.

Plant-inspired quercetin thin films: universal coatings and their postfunctionalization for non-biofouling applications

2021 ◽  
Author(s):  
Soojeong Cho ◽  
Hyeon Min Shin ◽  
Yeonwoo Jeong ◽  
Sunhee Kim ◽  
Ji Hwan Eom ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Chemistry

We developed quercetin surface chemistry that can be applied for various substrates and is able to postfunctionalize for hemocompatible coatings.

scholarly journals Antibacterial Surfaces, Thin Films, and Nanostructured Coatings

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 556
Author(s):  
Daniele Valerini
Keyword(s):  
Thin Films ◽  
Medical Devices ◽  
Nanostructured Coatings ◽  
Antibacterial Surfaces

Antibacterial surfaces can play a key role in a great number of everyday applications, spanning from biomedical purposes (medical devices, protection equipment, surgery tools, human implants, etc [...]

scholarly journals Influence of deposition parameters on the optical absorption of amorphous silicon thin films

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Lukas Terkowski ◽  
Iain W. Martin ◽  
Daniel Axmann ◽  
Malte Behrendsen ◽  
Felix Pein ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Absorption ◽  
Amorphous Silicon ◽  
Silicon Thin Films ◽  
Deposition Parameters

Processing by Pulsed Laser Deposition and Structural, Morphological and Chemical Characterization of Bi-Pb-Sr-Ca-Cu-O and Bi-Pb-Sb-Sr-Ca-Cu-O Thin Films

2010 ◽  
Vol 75 ◽  
pp. 202-207
Author(s):  
Victor Ríos ◽  
Elvia Díaz-Valdés ◽  
Jorge Ricardo Aguilar ◽  
T.G. Kryshtab ◽  
Ciro Falcony
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Room Temperature ◽  
Pulsed Laser ◽  
Chemical Characterization ◽  
Laser Deposition ◽  
Nominal Composition ◽  
Deposition Parameters ◽  
The Relationship

Bi-Pb-Sr-Ca-Cu-O (BPSCCO) and Bi-Pb-Sb-Sr-Ca-Cu-O (BPSSCCO) thin films were grown on MgO single crystal substrates by pulsed laser deposition. The deposition was carried out at room temperature during 90 minutes. A Nd:YAG excimer laser ( = 355 nm) with a 2 J/pulse energy density operated at 30 Hz was used. The distance between the target and substrate was kept constant at 4,5 cm. Nominal composition of the targets was Bi1,6Pb0,4Sr2Ca2Cu3O and Bi1,6Pb0,4Sb0,1Sr2Ca2Cu3OSuperconducting targets were prepared following a state solid reaction. As-grown films were annealed at different conditions. As-grown and annealed films were characterized by XRD, FTIR, and SEM. The films were prepared applying an experimental design. The relationship among deposition parameters and their effect on the formation of superconducting Bi-system crystalline phases was studied.

Fabrication of Polycrystalline Silicon on Glass from Fluorinated Precursors with the Aid of Atomic Hydrogen

1995 ◽  
Vol 403 ◽  
Author(s):  
T. Akasaka ◽  
D. He ◽  
I. Shimizu
Keyword(s):  
Thin Films ◽  
Atomic Hydrogen ◽  
Polycrystalline Silicon ◽  
In Situ Observation ◽  
Layer By Layer ◽  
High Quality ◽  
Deposition Parameters ◽  
Columnar Grains ◽  
Step Growth

AbstractHigh quality polycrystalline silicon was made on glass from fluorinated precursors by two step growth, i.e., (1) formation of seed crystals on glass by layer-by-layer(LL) technique and (2) grain-growth on the seeds. In LL technique, deposition of ultra-thin films and treatment with atomic hydrogen was repeated alternately. Columnar grains with 200 nm dia were grown epitaxy-like on the seeds by optimizing the deposition parameters under in situ observation with spectroscopic ellipsometry.

scholarly journals Improved Morphology of Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) Thin Films for All-Electrospray-Coated Organic Photovoltaic Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Yingjie Liao ◽  
Takeshi Fukuda ◽  
Norihiko Kamata
Keyword(s):  
Thin Films ◽  
High Performance ◽  
Photovoltaic Cells ◽  
Spray Coating ◽  
Organic Photovoltaic ◽  
Organic Photovoltaic Cells ◽  
Ambient Conditions ◽  
Deposition Parameters ◽  
Coating Methods ◽  
Organic Devices

Spray coating technique has been established as a promising substitute for the traditional coating methods in the fabrication of organic devices in many reports recently. Control of film morphology at the microscopic scale is critical if spray-coated devices are to achieve high performance. Here we investigate electrospray deposition protocols for the fabrication of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin films with a single additive system under ambient conditions at room temperature. Critical deposition parameters including solution composition, applied voltage, and relative humidity are discussed systematically. Optimized process for preparing homogenous PEDOT:PSS thin films is applied to all-electrospray-coated organic photovoltaic cells and contributes to a power conversion efficiency comparable to that of the corresponding all-spin-coated device.

The Materials Science of “Permeable Polysilicon” Thin Films

2001 ◽  
Vol 687 ◽  
Author(s):  
George M Dougherty ◽  
Timothy Sands ◽  
Albert P. Pisano
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Materials Science ◽  
Single Step ◽  
Process Window ◽  
Silicon Thin Films ◽  
Growth Regime ◽  
Deposition Parameters ◽  
Simple Kinetic Model ◽  
The Relationship

AbstractPolycrystalline silicon thin films that are permeable to fluids, known as permeable polysilicon, have been reported by several researchers. Such films have great potential for the fabrication of difficult to make MEMS structures, but their use has been hampered by poor process repeatability and a lack of physical understanding of the origin of film permeability and how to control it. We have completed a methodical study of the relationship between process, microstructure, and properties for permeable polysilicon thin films. As a result, we have determined that the film permeability is caused by the presence of nanoscale pores, ranging from 10-50 nm in size, that form spontaneously during LPCVD deposition within a narrow process window. The unusual microstructure within this process window corresponds to the transition between a semicrystalline growth regime, exhibiting tensile residual stress, and a columnar growth regime exhibiting compressive residual stress. A simple kinetic model is proposed to explain the unusual morphology within this transition regime. It is determined that measurements of the film residual stress can be used to tune the deposition parameters to repeatably produce permeable films for applications. The result is a convenient, single-step process that enables the elegant fabrication of many previously challenging structures.

AFM Study of Surface Morphology of Aluminum Nitride Thin Films

1995 ◽  
Vol 388 ◽  
Author(s):  
Yoshihisa Watanabe ◽  
Yoshikazu Nakamura ◽  
Shigekazu Hirayama ◽  
Yuusaku Naota
Keyword(s):  
Thin Films ◽  
Surface Morphology ◽  
Substrate Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Ion Beam ◽  
Soda Lime ◽  
Silicon Single Crystal ◽  
Soda Lime Glass ◽  
Average Roughness

AbstractAluminum nitride (AlN) thin films have been synthesized by ion-beam assisted deposition method. Film deposition has been performed on the substrates of silicon single crystal, soda-lime glass and alumin A. the influence of the substrate roughness on the film roughness is studied. the substrate temperature has been kept at room temperature and 473K and the kinetic energy of the incident nitrogen ion beam and the deposition rate have been fixed to 0.5 keV and 0.07 nm/s, respectively. the microstructure of the synthesized films has been examined by X-ray diffraction (XRD) and the surface morphology has been observed by atomic force microscopy(AFM). IN the XRD patterns of films synthesized at both room temperature and 473K, the diffraction line indicating the alN (10*0) can be discerned and the broad peak composed of two lines indicating the a1N (00*2) and a1N (10*1) planes is also observed. aFM observations for 100 nm films reveal that (1) the surface of the films synthesized on the silicon single crystal and soda-lime glass substrates is uniform and smooth on the nanometer scale, (2) the average roughness of the films synthesized on the alumina substrate is similar to that of the substrate, suggesting the evaluation of the average roughness of the film itself is difficult in the case of the rough substrate, and (3) the average roughness increases with increasing the substrate temperature.

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