Structural and physicochemical surface properties of Serratia marcescens strains

1992 ◽  
Vol 38 (10) ◽  
pp. 1033-1041 ◽  
Author(s):  
Henny C. Van der Mei ◽  
Marjorie M. Cowan ◽  
Michel J. Genet ◽  
Paul G. Rouxhet ◽  
Henk J. Busscher
Keyword(s):  
Infrared Spectroscopy ◽  
Zeta Potential ◽  
Cell Surface ◽  
Serratia Marcescens ◽  
Photoelectron Spectroscopy ◽  
Surface Concentration ◽  
Structural Features ◽  
Contact Angles ◽  
X Ray ◽  
Zeta Potentials

Serratia marcescens is an important pathogen with noteworthy hydrophobicity characteristics as assessed by microbial adhesion to hydrocarbons. However, the present knowledge on the surface characteristics of S. marcescens strains does not include physicochemical properties relevant for adhesion such as surface free energy and zeta potential. Also, little attention has been paid hitherto to the structural features and chemical composition of the cell surface. Therefore, as a primary aim of this paper, we characterized S. marcescens strains by means of contact angle and zeta potential measurements, X-ray photoelectron spectroscopy, and infrared spectroscopy. In addition, transmission electron microscopy on negatively stained (methylamine tungstate) and ruthenium red stained cells was employed to study structural features on the cell surface. Furthermore, as a secondary aim of this paper, the power of the various techniques to discriminate between strains was evaluated. Negative staining showed that S. marcescens RZ almost completely lost its surface fibrils upon increasing the growth temperature from 30 to 37 °C. This loss of surface fibrils was accompanied by a decrease in hydrophobicity, as measured by water contact angles on bacterial lawns. No significant differences in hexadecane contact angles were observed. Zeta potentials were only different for S. marcescens 3164, showing a considerably higher isoelectric point (IEP = 3.9) than the other strains involved (IEP about 2.5). X-ray photoelectron spectroscopy yielded differences in O/C, N/C, and P/C surface concentration ratios, which related with the IEPs of the strains, despite the fact that X-ray photoelectron spectroscopy is done on fully dehydrated cells, whereas zeta potentials are measured on cells in their physiological state. Infrared spectroscopy was not sufficiently surface sensitive to discriminate between these strains. N/C surface concentration ratios by X-ray photoelectron spectroscopy, which probes approximately 5 nm deep from the surface, were slightly higher for the pigmented, prodigiosin-containing strains RZ30 and 3164, although the presence of prodigiosin did not influence the cell surface hydrophobicity. Thus the prodigiosin is probably confined in deeper layers than probed by contact angles (approximately 0.3–0.5 nm). Key words: Serratia marcescens, fibrils, surface properties, hydrophobicity, zeta potential.

The Use of X-Ray Photoelectron Spectroscopy for the Study of Oral Streptococcal Cell Surfaces

1997 ◽  
Vol 11 (4) ◽  
pp. 388-394 ◽  
Author(s):  
H.C. Van Der Mei ◽  
H.J. Busscher
Keyword(s):  
Cell Surface ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Contact Angles ◽  
Microbial Cell ◽  
Cell Surfaces ◽  
Water Contact ◽  
X Ray

Physicochemical and structural properties of microbial cell surfaces play an important role in their adhesion to surfaces and are determined by the chemical composition of the outermost cell surface. Many traditional methods used to determine microbial cell wall composition require fractionation of the organisms and consequently do not yield information about the composition of the outermost cell surface. X-ray photoelectron spectroscopy (XPS) measures the elemental composition of the outermost cell surfaces of micro-organisms. The technique requires freeze-drying of the organisms, but, nevertheless, elemental surface concentration ratios of oral streptococcal cell surfaces with peritrichously arranged surface structures showed good relationships with physicochemical properties measured under physiological conditions, such as zeta potentials. Isoelectric points ap-peared to be governed by the relative abundance of oxygen- and nitrogen-containing groups on the cell surfaces. Also, the intrinsic microbial cell-surface hydrophobicity by water contact angles related to the cell-surface composition as by XPS and was highest for strains with an elevated isoelectric point. Inclusion of elemental surface compositions for tufted streptococcal strains caused deterioration of the relationships found. Interestingly, hierarchical cluster analysis on the basis of the elemental surface compositions revealed that, of 36 different streptococcal strains, only four S. rattus as well as nine S. mitis strains were located in distinct groups, well separated from the other streptococcal strains, which were all more or less mixed in one group.

scholarly journals A Novel Synthetic UV-Curable Fluorinated Siloxane Resin for Low Surface Energy Coating

Polymers ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 979 ◽  
Author(s):  
Chunfang Zhu ◽  
Haitao Yang ◽  
Hongbo Liang ◽  
Zhengyue Wang ◽  
Jun Dong ◽  
...  
Keyword(s):  
Surface Energy ◽  
Photoelectron Spectroscopy ◽  
Contact Angles ◽  
Proton Nuclear Magnetic Resonance ◽  
Energy Materials ◽  
Uv Curable ◽  
X Ray ◽  
Low Surface Energy ◽  
Low Concentrations ◽  
Siloxane Polymers

Low surface energy materials have attracted much attention due to their properties and various applications. In this work, we synthesized and characterized a series of ultraviolet (UV)-curable fluorinated siloxane polymers with various fluorinated acrylates—hexafluorobutyl acrylate, dodecafluoroheptyl acrylate, and trifluorooctyl methacrylate—grafted onto a hydrogen-containing poly(dimethylsiloxane) backbone. The structures of the fluorinated siloxane polymers were measured and confirmed by proton nuclear magnetic resonance and Fourier transform infrared spectroscopy. Then the polymers were used as surface modifiers of UV-curable commercial polyurethane (DR-U356) at different concentrations (1, 2, 3, 4, 5, and 10 wt %). Among three formulations of these fluorinated siloxane polymers modified with DR-U356, hydrophobic states (91°, 92°, and 98°) were obtained at low concentrations (1 wt %). The DR-U356 resin is only in the hydrophilic state at 59.41°. The fluorine and siloxane element contents were investigated by X-ray photoelectron spectroscopy and the results indicated that the fluorinated and siloxane elements were liable to migrate to the surface of resins. The results of the friction recovering assays showed that the recorded contact angles of the series of fluorinated siloxane resins were higher than the original values after the friction-annealing progressing.

scholarly journals Synthesis and characterization of nanoscale composite particles formed by 2D layers of Cu-Fe sulfide and Mg-based hydroxide

2021 ◽  
Author(s):  
Yuri Mikhlin ◽  
Roman Borisov ◽  
Sergey Vorobyev ◽  
Yevgeny Tomashevich ◽  
Alexander Romanchenko ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Localized Surface Plasmon ◽  
X Ray ◽  
Zeta Potentials ◽  
Dielectric Resonance ◽  
Magnetic Dynamic ◽  
20 Nm ◽  
Electron Energy Loss

Two-dimensional phenomena are attracting enormous interest at present and the search for novel 2D materials is very challenging. We propose here the layered material valleriite composed of altering atomic sheets of Cu-Fe sulfide and Mg-based hydroxide synthesized via a simple hydrothermal pathway as particles of 50-200 nm in the lateral size and 10-20 nm thick. The solid products and aqueous colloids prepared with various precursor ratios were examined using XRD, TEM, EDS, X-ray photoelectron spectroscopy (XPS), reflection electron energy loss spectroscopy (REELS), Raman, Mössbauer, UV-vis-NIR spectroscopies, magnetic, dynamic light scattering, zeta potential measurements. The material properties are largely determined by the narrow-gap (less than 0.5 eV) sulfide layers containing Cu+ and Fe3+ cations, monosulfide and minor polysulfide anions but are strongly affected by the hydroxide counterparts. Particularly, Fe distribution between sulfide (55-90%) and magnesium hydroxide layers is controlled through insertion of Al into the hydroxide part and by Cr and Co dopants entering both layers. Room-temperature Mössbauer signals of paramagnetic Fe3+ transformed to several Zeeman sextets with hyperfine magnetic fields up to 500 kOe in the sulfide layers at 4 K. Paramagnetic or more complicated characters were observed for valleriites with higher and lower Fe concentrations in hydroxide sheets, respectively. Valleriite colloids showed negative zeta potentials, suggesting negative electric charging of the hydroxide sheets, and optical absorption maxima between 500 nm and 700 nm, also depended on the Fe distribution. The last features observed also in the REELS spectra may be due to localized surface plasmon or, more likely, quasi-static dielectric resonance. The tunable composition, electronic, magnetic, optic and surface properties highlight valleriites as a rich platform for novel 2D composites promising for numerous applications.

scholarly journals Fabrication of Strontium Bismuth Oxides as Novel Battery-Type Electrode Materials for High-Performance Supercapacitors

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yinghui Han ◽  
Le Li ◽  
Yunpeng Liu ◽  
Xue Li ◽  
Xiaohan Qi ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Electrode Materials ◽  
Specific Capacity ◽  
Structural Features ◽  
High Electron ◽  
Strontium Content ◽  
X Ray ◽  
Bismuth Oxides ◽  
Improved Performance

A simple and efficient process method for the preparation of strontium bismuth oxides (SBOs) via an impregnation-calcination method is presented. The synthesized active materials are characterized using X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. The electrochemical performance of the as-synthesized SBO samples is observed to decrease gradually as the strontium content is increased from 25% to 50%. The SBO sample with a Sr/Bi ratio of 1 : 3 shows the highest specific capacitance of 1228.7 F g−1 (specific capacity of 204.8 mAh g−1) at a current density of 1 A g−1 and a good cycling stability (75.1%) over 3000 charge-discharge cycles. The improved performance of the supercapacitors can be attributed to the unique structural features resulting from the addition of appropriate portions of Sr, which supports high electron conductivity and rapid ion/electron transport within the electrode and at the electrode/electrolyte interface. All the results show that the SBOs have considerable potential for use as high-performance battery-type electrodes in supercapacitors.

X-ray photoelectron spectroscopy of low surface concentration mass-selected Ag clusters

2000 ◽  
Vol 113 (20) ◽  
pp. 9233-9238 ◽  
Author(s):  
James N. O’Shea ◽  
Joachim Schnadt ◽  
Staffan Andersson ◽  
Luc Patthey ◽  
Steffen Rost ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Concentration ◽  
X Ray ◽  
Ag Clusters

scholarly journals Activation Mechanism of Lead Ions in Perovskite Flotation with Octyl Hydroxamic Acid Collector

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 341 ◽  
Author(s):  
Yu Zheng ◽  
Yating Cui ◽  
Weiqing Wang
Keyword(s):  
Zeta Potential ◽  
Photoelectron Spectroscopy ◽  
Hydroxamic Acid ◽  
Relative Content ◽  
Lead Ions ◽  
Activation Mechanism ◽  
X Ray ◽  
Ft Ir ◽  
Acidic Conditions ◽  
Ir Analysis

The activation mechanism of lead ions (Pb2+) in perovskite flotation with an octyl hydroxamic acid collector was systematically investigated using microflotation experiments, zeta-potential measurements, adsorption tests, Fourier transform infrared (FT-IR) analysis, and X-ray photoelectron spectroscopy (XPS) analysis. The results of microflotation experiments and adsorption tests indicate that the presence of Pb2+ can promote the adsorption of octyl hydroxamic acid (OHA) on the perovskite surface and enhance the flotability of perovskite under weakly acidic conditions. The maximum recovery of 79.62% was obtained at pH 6.5 in the presence of Pb2+, and the maximum recovery of 57.93% was obtained at pH 5.7 without Pb2+. At pHs below 7, lead species are mainly present as Pb2+ and PbOH+ in the solution; besides this, the relative content of titanium increases on the perovskite surface. The adsorption of Pb2+ and PbOH+ on the perovskite surface makes the zeta-potential of perovskite shift positively, and increases the number of activated sites on the perovskite surface. FT-IR and XPS analyses confirm that OHA chemisorbs on the surface of Pb2+-activated perovskite and forms hydrophobic Pb-OHA complexes, which improve the flotability of perovskite.

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