scholarly journals Electrophoretic coating of amphiphilic chitosan colloids on regulating cellular behaviour

2013 ◽  
Vol 10 (86) ◽  
pp. 20130411 ◽  
Author(s):  
Yen-Jen Wang ◽  
Teng-Yuan Lo ◽  
Chieh-Hsi Wu ◽  
Dean-Mo Liu
Keyword(s):  
Stainless Steel ◽  
Umbilical Vein ◽  
Biochemical Properties ◽  
Stainless Steel Surface ◽  
Texture Surface ◽  
Force Microscopy ◽  
Cardiovascular Stents ◽  
Atomic Force ◽  
Cellular Behaviour ◽  
Umbilical Vein Endothelial Cells

In this communication, we report a facile nanotopographical control over a stainless steel surface via an electrophoretic deposition of colloidal amphiphilic chitosan for preferential growth, proliferation or migration of vascular smooth muscle cells (VSMCs) and human umbilical vein endothelial cells (HUVECs). Atomic force microscopy revealed that the colloidal surface exhibited a deposition time-dependent nanotopographical evolution, wherein two different nanotopographic textures indexed by ‘kurtosis’ ( R kur ) value were easily designed, which were termed as ‘sharp’ (i.e. high peak-to-valley texture) surface and ‘flat’ (i.e. low peak-to-valley texture) surface. Cellular behaviour of VSMCs and HUVECs on both surfaces demonstrated topographically dependent morphogenesis, adherent responses and biochemical properties in comparison with bare stainless steel. The formation of a biofunctionalized surface upon a facile colloidal chitosan deposition envisions the potential application towards numerous biomedical devices, and this is especially promising for cardiovascular stents wherein a new surface with optimized texture can be designed and is expected to create an advantageous environment to stimulate HUVEC growth for improved healing performance.

Atomic force microscopy measurement of leukocyte-endothelial interaction

2004 ◽  
Vol 286 (1) ◽  
pp. H359-H367 ◽  
Author(s):  
Xiaohui Zhang ◽  
Aileen Chen ◽  
Dina De Leon ◽  
Hong Li ◽  
Eisei Noiri ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Inflammatory Diseases ◽  
Leukocyte Adhesion ◽  
Umbilical Vein ◽  
Quantitative Measure ◽  
Dependent Manner ◽  
Average Force ◽  
Force Microscopy ◽  
Atomic Force ◽  
Umbilical Vein Endothelial Cells

Leukocyte adhesion to vascular endothelium is a key initiating step in the pathogenesis of many inflammatory diseases. In this study, we present real-time force measurements of the interaction between monocytic human promyelocytic leukemia cells (HL-60) cells and a monolayer of human umbilical vein endothelial cells (HUVECs) by using atomic force microscopy (AFM). The detachment of HL-60-HUVEC conjugates involved a series of rupture events with force transitions of 40–100 pN. The integrated force of these rupture events provided a quantitative measure of the adhesion strength on a whole cell level. The AFM measurements revealed that HL-60 adhesion is heightened in the borders formed by adjacent HUVECs. The average force and mechanical work required to detach a single HL-60 from the borders of a tumor necrosis factor-α-activated HUVEC layer were twice as high as those of the HUVEC bodies. HL-60 adhesion to the monolayer was significantly reduced by a monoclonal antibody against β1-integrins and partially inhibited by antibodies against selectins ICAM-1 and VCAM-1 but was not affected by anti-αVβ3. Interestingly, adhesion was also inhibited in a dose-dependent manner (IC50≈ 100 nM) by a cyclic arginine-glycine-aspartic acid (cRGD) peptide. This effect was mediated via interfering with the VLA-4-VCAM-1 binding. In parallel measurements, transmigration of HL-60 cells across a confluent HUVEC monolayer was inhibited by the cRGD peptide and by both anti-β1and anti-αVβ3antibodies. In conclusion, these data demonstrate the role played by β1-integrins in leukocyte-endothelial adhesion and transmigration and the role played by αVβ3in transmigration, thus underscoring the high efficacy of cRGD peptide in blocking both the adhesion and transmigration of monocytes.

Effect of raised temperature on a stainless-steel surface by ambient atomic-force microscopy

1993 ◽  
Vol 51 ◽  
pp. 228-229
Author(s):  
Pan S. Jung
Keyword(s):  
Atomic Force Microscopy ◽  
Stainless Steel ◽  
Steel Surface ◽  
Heating Element ◽  
Metallic Surface ◽  
Stainless Steel Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Soldering Iron ◽  
Surface Changes

We report images from atomic force microscopy (AFM) of a heated metallic surface performed under an ambient environment. The stainless steel surface was heated up to 121C, which is limited only by the capacitive heating element used (100W). We observed that the topography of the surface changes dramatically. It is found that at high temperatures, the surface appears flat compared with the presence of many round bumps observed on the same sample at room temperature when the ambient humidity is high. To the best of our knowledge, this is the first report on ambient AFM performed on a metallic surface above 100C.Most AFM systems adopt moving sample stages [1]. In this case, it is difficult to implement heavy heating heating elements and a heat reservoir block. For this experiment, the TAK3 from AT Corporation [2] is used. The sample stage is kept stationary and the heating element (the tip of a soldering iron) is fixed firmly on one side of a surface of the block using a screw.

Fibronectin modified TiO2 nanotubes modulate endothelial cell behavior

2018 ◽  
Vol 33 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Ziyang Jin ◽  
Xufeng Yan ◽  
Guiyong Liu ◽  
Min Lai
Keyword(s):  
Photoelectron Spectroscopy ◽  
Umbilical Vein ◽  
Cell Counting ◽  
Cellular Functions ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Substrate Surfaces ◽  
Umbilical Vein Endothelial Cells

Cardiovascular disease has become a great threat to the health of mankind; current titanium (Ti) stents fail due to late stent thrombosis caused by the lack of re-endothelialization of the Ti stent. The objective of this study was to design a novel cardiovascular Ti implant with improved surface biocompatibility. TiO2 nanotubes with a diameter of 110 nm were anodized at a constant voltage of 30 V, and fibronectin was immobilized onto the TiO2 nanotubes using polydopamine. The element composition, morphology, and wettability of the different substrate surfaces were characterized by x-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and contact angle measurements, respectively, confirming the successful immobilization of fibronectin. In vitro experiments including immunofluorescence staining, Cell Counting Kit-8 (CCK-8), and nitric oxide (NO) and prostacyclin (PGI2) release demonstrate that fibronectin modified TiO2 nanotubes supported cell adhesion, proliferation, and normal cellular functions of human umbilical vein endothelial cells (HUVECs). These methodologies can be applied for future fabrication of cardiovascular stents.

scholarly journals Investigations of reconstruction of passivation layer on stainless steel surface using AFM-based techniques

2018 ◽  
Vol 36 (3) ◽  
pp. 381-386 ◽  
Author(s):  
Marlena Błaszczyk ◽  
Martyna Durko ◽  
Zuzanna Iwanicka ◽  
Paweł Lochyński ◽  
Andrzej Sikora
Keyword(s):  
Stainless Steel ◽  
Passivation Layer ◽  
Stainless Steel Surface ◽  
Reconstruction Process ◽  
Force Microscopy ◽  
Atomic Force ◽  
Steel Technology ◽  
Passivation Layers ◽  
Semicontact Mode ◽  
The Impact

AbstractContinuous development of stainless steel technology forced by the increase in the growing demands on the operating parameters of various stainless steel alloys, is the motivation for implementation of research for understanding the complexity of electrochemical processes ongoing on the surface of a material during various technological processes and during exploitation of the finished components. In this paper, the use of atomic force microscopy (AFM) is presented as a tool for observation of reconstruction process of passivation layers on the surface of previously electropolished stainless steel. For this purpose, a technique called nanoscratching was used, in which scratches are made on the surface of a material by means of diamond scanning probe, which violates the continuity of the passivation layer. Then, the dynamics of the process of reconstruction of that layer was assessed using continuous imaging of the scratched area in AFM semicontact mode. Studies of this type can be used to evaluate the impact of various factors on the spontaneous reconstruction of the passivation layer as well as possible susceptibility of the material on the course of corrosion processes initiated as a result of mechanical defects arising during operation of the material. By using the AFM, it was possible to observe changes in the depth of scratches with a subnanometer resolution. Obtained results proved that the presented AFM application allowed observation of the dynamics of passivation layer reconstruction process in a quantitative fashion, therefore it seems to be a very useful tool in the investigation of the impact of various conditions on this phenomenon. The results showed that changes in surface modification were occurring in a continuous manner. Changing dynamics of said process was presented. It should be underlined that no such experiments have been reported so far.

scholarly journals Anti-Bacterial and Anti-Fouling Capabilities of Poly(3,4-Ethylenedioxythiophene) Derivative Nanohybrid Coatings on SUS316L Stainless Steel by Electrochemical Polymerization

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1467 ◽  
Author(s):  
Chuan-Chih Hsu ◽  
Yu-Wei Cheng ◽  
Che-Chun Liu ◽  
Xin-Yao Peng ◽  
Ming-Chi Yung ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Photoelectron Spectroscopy ◽  
Negative Charge ◽  
Electrochemical Polymerization ◽  
Inhibition Zone ◽  
Lower Surface ◽  
Water Contact ◽  
Force Microscopy ◽  
Cardiovascular Stents ◽  
Atomic Force

We have successfully fabricated poly(3,4-ethylenedioxythiophene) (PEDOT) derivative nanohybrid coatings on flexible SUS316L stainless steel by electrochemical polymerization, which can offer anti-fouling and anti-bacterial capabilities. PEDOT derivative nanohybrids were prepared from polystyrene sulfonates (PSS) and graphene oxide (GO) incorporated into a conducting polymer of PEDOT. Additionally, the negative charge of the PEDOT/GO substrate was further modified by poly-diallyldimethylammonium chloride (PDDA) to form a positively charged surface. These PEDOT derivative nanohybrid coatings could provide a straightforward means of controlling the surface energy, roughness, and charges with the addition of various derivatives in the electrochemical polymerization and electrostatically absorbed process. The characteristics of the PEDOT derivative nanohybrid coatings were evaluated by Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), water contact angle, and surface potential (zeta potential). The results show that PEDOT/PSS and PEDOT/GO nanohybrid coatings exhibit excellent anti-fouling capability. Only 0.1% of bacteria can be adhered on the surface due to the lower surface roughness and negative charge surface by PEDOT/PSS and PEDOT/GO modification. Furthermore, the anti-bacterial capability (7 mm of inhibition zone) was observed after adding PDDA on the PEDOT/GO substrates, suggesting that the positive charge of the PEDOT/GO/PDDA substrate can effectively kill bacteria (Staphylococcus aureus). Given their anti-fouling and anti-bacterial capabilities, PEDOT derivative nanohybrid coatings have the potential to be applied to biomedical devices such as cardiovascular stents and surgical apparatus.

scholarly journals Hydroxychloroquine protects the annexin A5 anticoagulant shield from disruption by antiphospholipid antibodies: evidence for a novel effect for an old antimalarial drug

Blood ◽  
2010 ◽  
Vol 115 (11) ◽  
pp. 2292-2299 ◽  
Author(s):  
Jacob H. Rand ◽  
Xiao-Xuan Wu ◽  
Anthony S. Quinn ◽  
Anthony W. Ashton ◽  
Pojen P. Chen ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Endothelial Cells ◽  
Antiphospholipid Antibodies ◽  
Umbilical Vein ◽  
Trophoblast Cell ◽  
Annexin A5 ◽  
Force Microscopy ◽  
Plasma Coagulation ◽  
Atomic Force ◽  
Umbilical Vein Endothelial Cells

Abstract Annexin A5 (AnxA5) is a potent anticoagulant protein that crystallizes over phospholipid bilayers (PLBs), blocking their availability for coagulation reactions. Antiphospholipid antibodies disrupt AnxA5 binding, thereby accelerating coagulation reactions. This disruption may contribute to thrombosis and miscarriages in the antiphospholipid syndrome (APS). We investigated whether the antimalarial drug, hydroxychloroquine (HCQ), might affect this prothrombotic mechanism. Binding of AnxA5 to PLBs was measured with labeled AnxA5 and also imaged with atomic force microscopy. Immunoglobulin G levels, AnxA5, and plasma coagulation times were measured on cultured human umbilical vein endothelial cells and a syncytialized trophoblast cell line. AnxA5 anticoagulant activities of APS patient plasmas were also determined. HCQ reversed the effect of antiphospholipid antibodies on AnxA5 and restored AnxA5 binding to PLBs, an effect corroborated by atomic force microscopy. Similar reversals of antiphospholipid-induced abnormalities were measured on the surfaces of human umbilical vein endothelial cells and syncytialized trophoblast cell lines, wherein HCQ reduced the binding of antiphospholipid antibodies, increased cell-surface AnxA5 concentrations, and prolonged plasma coagulation to control levels. In addition, HCQ increased the AnxA5 anticoagulant activities of APS patient plasmas. In conclusion, HCQ reversed antiphospholipid-mediated disruptions of AnxA5 on PLBs and cultured cells, and in APS patient plasmas. These results support the concept of novel therapeutic approaches that address specific APS disease mechanisms.

Micromechanisms of Hydrogen-Assisted Cracking in Super Duplex Stainless Steel Investigated by Scanning Probe Microscopy

2014 ◽  
Author(s):  
Bai An ◽  
Takashi Iijima ◽  
Chris San Marchi ◽  
Brian Somerday
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Scanning Tunneling ◽  
Super Duplex Stainless Steel ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hydrogen Assisted Cracking ◽  
Cracking Mechanisms ◽  
Localized Plastic Deformation

Understanding the micromechanisms of hydrogen-assisted fracture in multiphase metals is of great scientific and engineering importance. By using a combination of scanning electron microscopy (SEM), scanning tunneling microscopy (STM), atomic force microscopy (AFM) and magnetic force microscopy (MFM), the micromorphology of fracture surface and microcrack formation in hydrogen-precharged super duplex stainless steel 2507 are characterized from microscale to nanoscale. The results reveal that the fracture surfaces consist of quasi-brittle facets with riverlike patterns at the microscale, which exhibit rough irregular patterns or remarkable quasi-periodic corrugation patterns at the nanoscale that can be correlated with highly localized plastic deformation. The microcracks preferentially initiate and propagate in ferrite phase and are stopped or deflected by the boundaries of the austenite phase. The hydrogen-assisted cracking mechanisms in super duplex stainless steel are discussed according to the experimental results and hydrogen-enhanced localized plasticity theory.

Hydrogen Transport and Hydrogen-Assisted Cracking in SUS304 Stainless Steel During Deformation at Low Temperatures

2015 ◽  
Author(s):  
Lin Zhang ◽  
Bai An ◽  
Takashi Iijima ◽  
Chris San Marchi ◽  
Brian Somerday
Keyword(s):  
Stainless Steel ◽  
Hydrogen Embrittlement ◽  
Room Temperature ◽  
Hydrogen Release ◽  
Hydrogen Transport ◽  
Force Microscopy ◽  
Atomic Force ◽  
Strain Induced Martensite ◽  
Hydrogen Assisted Cracking ◽  
Slip Planes

The behaviors of hydrogen transport and hydrogen-assisted cracking in hydrogen-precharged SUS304 austenitic stainless steel sheets in a temperature range from 177 to 298 K are investigated by a combined tensile and hydrogen release experiment as well as magnetic force microscopy (MFM) based on atomic force microscopy (AFM). It is observed that the hydrogen embrittlement increases with decreasing temperature, reaches a maximum at around 218 K, and then decreases with further temperature decrease. The hydrogen release rate increases with increasing strain until fracture at room temperature but remains near zero level at and below 218 K except for some small distinct release peaks. The MFM observations reveal that fracture occurs at phase boundaries along slip planes at room temperature and twin boundaries at 218 K. The role of strain-induced martensite in the hydrogen transport and hydrogen embrittlement is discussed.

Sign in / Sign up

Export Citation Format

Share Document