scholarly journals Surface Probe Linker with Tandem Anti-Fouling Properties for Application in Biosensor Technology

Biosensors ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 20 ◽  
Author(s):  
Sandro Spagnolo ◽  
Brian De La Franier ◽  
Tibor Hianik ◽  
Michael Thompson
Keyword(s):  
Recombinant Proteins ◽  
Quartz Crystal ◽  
Large Degree ◽  
Acoustic Sensor ◽  
The Novel ◽  
Crystal Surfaces ◽  
Biosensor Technology ◽  
Surface Probe ◽  
Coated Surface ◽  
Coated Surfaces

This paper describes the anti-fouling capability of the novel monolayer-forming surface linker 3-(3-(trichlorosilylpropyloxy) propanoyl chloride (MEG-Cl). This compound was successfully attached to quartz crystal surfaces which are employed in an electromagnetic piezoelectric acoustic sensor (EMPAS) configuration. The MEG-Cl coated surface was both employed with Ni-NTA for the binding of recombinant proteins and for the tandem property of the avoidance of fouling from serum and milk. The MEG-Cl coated surfaces were found to provide a large degree of anti-fouling on the EMPAS device, and were comparable to previously studied MEG-OH surfaces. Importantly, the monolayer continued to provide anti-fouling capability to the biosensor following extension with Ni-NTA in place. Accordingly, this surface linker provides an attractive system for use in biosensor technology in terms of both its anti-fouling and linking properties.

scholarly journals Anti-Thrombin, Anti-Adhesive, Anti-Migratory, and Anti-Proliferative Activities of Sulfated Galactans from the Tropical Green Seaweed, Udotea flabellum

Marine Drugs ◽  
2018 ◽  
Vol 17 (1) ◽  
pp. 5 ◽  
Author(s):  
Maxsuell Mendes Marques ◽  
Fernando Presa ◽  
Rony Viana ◽  
Mariana Costa ◽  
Monica Amorim ◽  
...  
Keyword(s):  
Antitumor Agents ◽  
Anticoagulant Activity ◽  
Sulfated Polysaccharide ◽  
Northeastern Brazil ◽  
Sulfated Galactans ◽  
Green Seaweed ◽  
Coated Surface ◽  
Time Test ◽  
Coated Surfaces

In this study, sulfated polysaccharide-rich extracts were isolated from 22 tropical seaweeds (4 red, 11 brown, and 7 green) found in northeastern Brazil, and evaluated for the role of anticoagulant agents. Fifteen of the extracts showed anticoagulant activity, including all the extracts from green seaweeds. Udotea flabellum (a green seaweed) extract was the most potent, requiring an amount of only 3 µg to double the plasma coagulation time in the activated partial thromboplastin time test. A similar result was obtained with 1 µg of heparin. Two sulfated homogalactans with anticoagulant activity, F-I (130 kDa) and F-II (75 kDa), were isolated from this extract using several bio-guided purification steps. Their anticoagulant activity, as well as properties related to antitumor activity (anti-proliferative, anti-adhesive, and anti-migratory), were accessed. Their anticoagulant activities were close to that of heparin. We found that F-I and F-II (0.5–10 μg/mL) were not able to directly inhibit thrombin. In the presence of anti-thrombin, F-I (0.5 μg/mL) was more effective than heparin (0.5 μg/mL) in inhibiting thrombin, while F-II showed similar effects as heparin. F-I and F-II also inhibited B16-F10 (murine melanoma cells) adhesion, migration, and proliferation on a fibronectin-coated surface, but not on laminin- or collagen I-coated surfaces. Except for the antiproliferative activity, the other effects of F-I and F-II were eliminated upon their desulfation (~50%), indicating that the degree of sulfation is not as important for F-I and F-II anti-proliferative activity as the sulfation position. Taken together, the results provide strong evidence for the potential utility of sulfated galactans from U. flabellum, making these compounds an interesting option for future investigations that aim to design new anticoagulant/antitumor agents.

Condensation of Low-Surface-Tension Fluids on Microstructured Surfaces at Low Temperature

2017 ◽  
Author(s):  
Abulimiti Aili ◽  
Qiaoyu Ge ◽  
TieJun Zhang
Keyword(s):  
Heat Transfer ◽  
Surface Tension ◽  
Low Temperature ◽  
High Surface ◽  
Condensation Heat Transfer ◽  
Lubricant Oil ◽  
Microstructured Surfaces ◽  
Performance Deterioration ◽  
Coated Surface ◽  
Coated Surfaces

Filmwise condensation of a low surface tension fluid (i.e. refrigerant) on microstructured aluminum surfaces is studied to investigate the effect of the structures on condensation heat transfer at low temperature. The hypothesis is that the structures may cause thinning of the condensate film at micro-scales, thus resulting in an enhancement of condensation heat transfer. However, the structures may also decrease the mobility of the condensate near the surface due to increased friction, thus potentially leading to performance deterioration. The aim of this work is to investigate which of the two counteracting mechanisms dominate during filmwise condensation. Condensation experiments are carried out in a low-temperature vacuum chamber. Compared with the Nusselt model of condensation, the microstructured surfaces, either coated or uncoated, show similar performance, with potentially slight enhancement at low subcooling degree and slight deterioration at high subcooling degree. When the microstructured and silane-coated surface is infused with a non-volatile and very low-surface-tension lubricant oil, the lubricant is displaced by the condensate and there is almost no change in the condensation performance. Our results show that, unlike the case of dropwise condensation of high-surface tension fluids, microstructured and coated surfaces with/without infusing oil is not exciting to enhanced filmwise condensation of low-surface-tension fluids.

scholarly journals Fc receptor modulation in mononuclear phagocytes maintained on immobilized immune complexes occurs by diffusion of the receptor molecule.

1983 ◽  
Vol 157 (6) ◽  
pp. 2121-2139 ◽  
Author(s):  
J Michl ◽  
M M Pieczonka ◽  
J C Unkeless ◽  
G I Bell ◽  
S C Silverstein
Keyword(s):  
Plasma Membrane ◽  
Protein Biosynthesis ◽  
Fc Receptor ◽  
Mononuclear Phagocytes ◽  
Receptor Modulation ◽  
Igg Binding ◽  
Mouse Macrophages ◽  
Coated Surface ◽  
Coated Surfaces ◽  
Antigen Antibody

We describe a method for synchronously assembling antigen-antibody complexes underneath macrophages adherent to an antigen-coated surface. We have used this method to study the mechanism of Fc receptor (FcR) disappearance that occurs when resident and thioglycollate-elicited mouse macrophages are cultured on immune complex-coated surfaces. Erythrocytes opsonized with IgG (E(IgG) and a monoclonal antibody (2.4G2 IgG) directed against the trypsin-resistant FcR (FcRII) were used as indicators of the presence and distribution of FcRII molecules on the macrophage plasma membrane. Inhibitors of aerobic (NaCN) and anerobic (2-deoxyglucose, NaF) glycolysis and pinocytosis, of protein biosynthesis (cycloheximide), and of cytoskeletal function (cytochalasin B and D, colchicine, podophyllotoxin, taxol) did not reduce the rate or extent of FcRII modulation. Moreover, treatment of the macrophages with 0.1-0.5% formaldehyde did not reduce the extent of FcRII modulation as measured by the disappearance of E(IgG) binding sites. FcRII modulation was markedly slowed when the temperature was decreased to 2-4 degrees C. These results prove that FcRII modulation is governed by diffusion of the receptor in the plasma membrane. From the speed of FcRII disappearance from the macrophage's upper surface we calculate that the receptor has a diffusion coefficient at 37 degrees C of 2.5 X 10(-9) cm2/s. This finding indicates that FcRII, in its unligated form, is not linked to the macrophage's cytoskeleton, and that the receptor is capable of accommodating spatially to any distribution of ligands on a particle's surface.

Platelets selectively enhance lymphocyte adhesion on subendothelial matrix under arterial flow conditions

2012 ◽  
Vol 108 (08) ◽  
pp. 328-337 ◽  
Author(s):  
Maria Ersoy ◽  
Paul Hjemdahl ◽  
Naphtali Savion ◽  
David Varon ◽  
Galia Spectre ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
B Cells ◽  
Nk Cells ◽  
Platelet Activation ◽  
Platelet Adhesion ◽  
Nk Cell ◽  
Lymphocyte Adhesion ◽  
Subendothelial Matrix ◽  
Coated Surface ◽  
Coated Surfaces

SummaryPlatelet adhesion at sites of cardiovascular injury may facilitate leukocyte deposition. We asked if and how platelets enhance lymphocyte adhesion on different subendothelial matrix protein (SEMP)-coated surface at arterial shear stress. Hirudinised whole blood was subjected to an arterial shear rate (500 s−1) in a Cone and Plate(let) analyser (CPA) for 5 minutes using plates coated with bovine serum albumin (BSA), collagen, fibrinogen, von Willebrand factor (vWF), or fibronectin. Platelet and lymphocyte adhesion were monitored by CPA and flow cytometry. Exposure of blood to collagen, fibrinogen, and vWF-coated surfaces induced platelet activation. The most marked effect was seen with collagen-coating, which markedly enhanced the adhesion of all lymphocyte subpopulations compared to BSA-coating. Fibrinogen-coating supported both T and NK cell adhesion, while vWF-coated surface only enhanced NK cell deposition. In contrast, fibronectin enhanced neither platelet activation nor lymphocyte adhesion. Moreover, platelets preferentially facilitated adhesion of large CD4+ and CD8+ T cells and NK cells, and of small B cells. Enhanced cell adhesion of larger lymphocytes was associated with elevated platelet conjugation and higher lymphocyte expression of PSGL-1, Mac-1, and CD40L. The enhancement of lymphocyte adhesion was totally platelet-dependent, and was abolished in platelet-depleted blood. Moreover, blockade of the platelet adhesion molecules P-selectin, GPIIb/IIIa, and CD40L attenuated platelet-dependent lymphocyte deposition. In conclusion, platelets support lymphocyte adhesion on SEMP-coated surfaces under arterial shear. The enhancement is selective for large T and NK cells and small B cells.

Radiation Induced Surface Activation on SUS304 Rod Surface Coated With Thin Film Layer Formed by Vacuum Evaporation Method

2008 ◽  
Author(s):  
Jian Zhang ◽  
Kaichiro Mishima ◽  
Naoki Sugitani ◽  
Masahiro Hino ◽  
Tomoji Takamasa
Keyword(s):  
Gamma Ray ◽  
Vacuum Evaporation ◽  
Outer Diameter ◽  
Evaporation Method ◽  
Thin Film Layer ◽  
Radiation Induced ◽  
Gamma Ray Irradiation ◽  
Film Layer ◽  
Coated Surface ◽  
Coated Surfaces

In this study, the effect of film layer deposited on a metal surface by vacuum evaporation method on the RISA phenomenon was investigated from the view points of surface wettability and quenching velocity. Test rods were made of SUS304 with the outer diameter of 24mm and the length of 150mm. Four kinds of materials, i.e. titanium, zircaloy-II, germanium and silicon, were deposited separately on the half-circumference surface of a SUS304 rod with thickness of 200 nm. It was concluded that the RISA effect was observed on the film-coated surfaces after gamma-ray irradiation, which is similar to that on an oxide layer of SUS304 surface. It was also found that the quenching velocity on film-coated surfaces was much faster than that on an un-coated surface.

Experimental Investigation on the Anti-Fouling and Heat Transfer Performance of the Coated Surfaces

2010 ◽  
Author(s):  
Zhi-ming Xu ◽  
Ling Chen ◽  
Ying-lun Gao ◽  
Zhong-bin Zhang
Keyword(s):  
Heat Transfer ◽  
Base Metal ◽  
Heat Transfer Performance ◽  
Solution Concentration ◽  
Solution Temperature ◽  
Transfer Performance ◽  
Characteristic Parameters ◽  
Temperature Solution ◽  
Coated Surface ◽  
Coated Surfaces

The main purpose of this investigation was to study the anti-fouling and heat transfer performance of coated surfaces (ECTFE, FEP, PTFE and PFA). In the present investigation, the heat transfer performance of the coated surfaces was compared to base metal surfaces, and crystallization fouling experiments of coated surfaces were carried out under various operating parameters such as solution temperature, solution concentration and hydrodynamics of the system. The characteristic parameters of the coated surface, such as surface roughness, surface contour, contact angle and surface energy were measured and calculated, which were used to analyze the anti-fouling performances of the coated surface. The results show that compared with the base metal surface, Nusselt number of coated surfaces decrease. But coated surfaces have advantage on anti-fouling ability.

scholarly journals Effect of Sand Coating with Solution on Bond Strength of Bamboo

2019 ◽  
Vol 8 (9) ◽  
pp. 1269-1273
Keyword(s):  
Bond Strength ◽  
Smooth Surface ◽  
Energy Sources ◽  
Manufacturing Processes ◽  
Pull Out ◽  
Natural Energy ◽  
Coated Surface ◽  
Increasing Demand ◽  
Coated Surfaces ◽  
Surface Bond

In a developing country like India, there is an increasing demand for RCC. The major component of RCC is steel. Steel is an alloy of carbon. In manufacturing processes of steel lots of energy is required. For such energy, lots of natural energy sources are used which can adversely affect the environment. For sustainable development, Bamboo may be a proper replacement for steel. Bamboo is fast growing grass which easily cultivated in any types of land. For replacement of bamboo, the bond between bamboo and concrete must be strong. The bond strength of bamboo and concrete is a major concern in the use of bamboo. The surface of the bamboo is naturally coated and has a smooth surface. Due to smooth surface bond strength is decreasing. For increasing bond strength there must be the proper coating for bamboo. In this paper, a solution is used for coating. For roughness, the surface is coated with sand with a solution. For comparing bond strength of different coated surface pull out the test is carried out. For pull out, test samples with the various coated surfaces are cast and tested after 7, 14 and 28 days. The result shows an increase in bond strength of the coated surface.

Presumptive mesoderm cells from Xenopus laevis gastrulae attach to and migrate on substrata coated with fibronectin or laminin

1986 ◽  
Vol 86 (1) ◽  
pp. 109-118
Author(s):  
N. Nakatsuji
Keyword(s):  
Xenopus Laevis ◽  
Cell Attachment ◽  
Heparan Sulphate ◽  
Ion Concentration ◽  
Collagen Type Iv ◽  
Active Movement ◽  
Animal Pole ◽  
Type Iv ◽  
Coated Surface ◽  
Coated Surfaces

During amphibian gastrulation, presumptive mesoderm cells migrate from the blastopore towards the animal pole along the inner surface of the ectodermal layer. Their natural substratum is a network of anastomosing extracellular matrix fibrils, which contains fibronectin and laminin, as shown by immunostaining. If the fibril network is transferred onto a coverslip from the ectodermal layer, dissociated mesodermal cells readily attach to such conditioned surfaces and show active migration in a medium of high pH and low calcium ion concentration. In the present study, the surface of tissue culture dishes was coated with fibronectin, laminin, collagen type IV or heparan sulphate, to examine the effects on cell attachment and movement. The presumptive mesoderm cells from Xenopus laevis gastrulae showed rapid adhesion and active movement on the fibronectin- or laminin-coated surfaces. Cell adhesion was stronger and the mean rate of movement was higher on the fibronectin-coated surface than on the laminin-coated surface. The dissociated ectodermal cells did not attach to the fibronectin- or laminin-coated surfaces. The mesodermal cells did not attach to the collagen-, or heparan sulphate-coated surfaces, showing that these components of the basement membrane cannot serve as an adequate substratum for the mesoderm cells, at least by themselves.

scholarly journals Microstructure and Wear Properties of FeCrC, FeW and Feti Modified Iron Based Alloy Coating Deposited by PTA Process on AISI 430 Steel

2014 ◽  
Vol 59 (3) ◽  
pp. 925-933 ◽  
Author(s):  
T. Teker ◽  
S Karataş ◽  
S. O. Yilmaz
Keyword(s):  
Steel Substrate ◽  
Alloy Coating ◽  
Processing Parameters ◽  
X Ray Diffraction ◽  
Wear Properties ◽  
Composite Surface ◽  
Dendritic Phase ◽  
Coated Surface ◽  
Coated Surfaces ◽  
Aisi 430

Abstract The plasma transferred arc (PTA) process was used for developing wear resistance of AISI 430 steel substrate. Appropriate quantities of FeCrC, FeW and FeTi powders were combined to create conditions that synthesized M7C3 particles into reinforced Fe-based composite surface coating. The phase transformations on new created coated surfaces were comprehensively examined by using a combination of scanning electron microscopy (SEM), microanalysis by energy dispersive spectrometry (EDS), X-Ray diffraction (XRD), microhardness and abrasive wear tests. The microstructure studies of the superficial layers of the coating revealed presence of a mixture of the dendritic phase structure of austenite (γ) and fine eutectic M7C3 carbides. The results show that; the concentrations of the elements (Cr, W, Ti) added as ferroalloys, the size of dendrites formed in the coated surface, the change of hardness of the coated surfaces, the carbide volume rate and thickness of the coating changed by the variation of the processing parameters (ratio of reinforcement particulates and heat input).

scholarly journals Adsorption of Extracellular Chromosomal DNA and Its Effects on Natural Transformation of Azotobacter vinelandii

2010 ◽  
Vol 76 (13) ◽  
pp. 4179-4184 ◽  
Author(s):  
Nanxi Lu ◽  
Julie L. Zilles ◽  
Thanh H. Nguyen
Keyword(s):  
Natural Transformation ◽  
Azotobacter Vinelandii ◽  
Soil Surface ◽  
Extracellular Dna ◽  
Chromosomal Dna ◽  
Dna Adsorption ◽  
Silica Surfaces ◽  
Rigid Conformation ◽  
Coated Surface ◽  
Coated Surfaces

ABSTRACT To better understand the influence of environmental conditions on the adsorption of extracellular chromosomal DNA and its availability for natural transformation, the amount and conformation of adsorbed DNA were monitored under different conditions in parallel with transformation assays using the soil bacterium Azotobacter vinelandii. DNA adsorption was monitored using the technique of quartz crystal microbalance with dissipation (QCM-D). Both silica and natural organic matter (NOM) surfaces were evaluated in solutions containing either 100 mM NaCl or 1 mM CaCl2. The QCM-D data suggest that DNA adsorbed to silica surfaces has a more compact and rigid conformation in Ca2+ solution than in Na+ solution and that the reverse is true when DNA is adsorbed to NOM surfaces. While the amounts of DNA adsorbed on a silica surface were similar for Ca2+ and Na+ solutions, the amount of DNA adsorbed on an NOM-coated surface was higher in Ca2+ solution than in Na+ solution. Transformation frequencies for dissolved DNA and DNA adsorbed to silica and to NOM were 6 × 10−5, 5 × 10−5, and 2.5 × 10−4, respectively. For NOM-coated surfaces, transformation frequencies from individual experiments were 2- to 50-fold higher in the presence of Ca2+ than in the presence of Na+. The results suggest that groundwater hardness (i.e., Ca2+ concentration) will affect the amount of extracellular DNA adsorbed to the soil surface but that neither adsorption nor changes in the conformation of the adsorbed DNA will have a strong effect on the frequency of natural transformation of A. vinelandii.

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