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Louise Wogelred, Fredrik Höök, Björn Agnarsson, Peter Sjövall
Accurate detection and quantification of individual molecules is important for the development of improved diagnostic methods as well as biochemical characterization of disease progression and treatments. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a surface analysis technique capable of imaging the distribution of specific molecules on surfaces with a high spatial resolution (<1 μm) and high sensitivity. ToF-SIMS is particularly suitable for detection of molecules up to ∼2 kDa, including lipids, whereas larger molecules, such as peptides and proteins, are fragmented during analysis, which makes them difficult to identify...
March 15, 2018: Biointerphases
Marcel Heeger, Bonnie J Tyler, Martin Körsgen, Heinrich F Arlinghaus
In this study, the influence of two different cluster primary ions in laser secondary neutral mass spectrometry (Laser-SNMS) has been investigated. Despite the many advantages of Laser-SNMS, fragmentation of neutral organic molecules during both sputtering and photoionization has limited its efficiency for the study of large organic and biological molecules. Cluster ion sputtering, and in particular large argon gas cluster sputtering, has been proposed as a means of reducing this fragmentation. Molecules of 9-fluorenylmethoxycarbonyl-pentafluoro-l-phenylalanine were sputtered using Bi3 + and Ar2000 + cluster primary ions, and the desorbed neutral species ("secondary neutrals") were postionized using a 7...
March 2, 2018: Biointerphases
Hyun Kyong Shon, Shin Hye Kim, Sohee Yoon, Chan Young Shin, Tae Geol Lee
Brain imaging using time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been reported to produce the distorted biomolecular distributions due to the cholesterol-induced matrix effect when cholesterol migrates to the surface, particularly in white matter, which contains a high level of cholesterol. Frozen-hydrated analysis has been used to inhibit the movement of cholesterol in the brain. In this paper, the authors propose new sample preparation and drying methods that can be used to obtain accurate biomolecular images at room temperature, instead of frozen-hydrated analysis using liquid-nitrogen, which must be continuously supplied to maintain the sample at -160 °C during the experiment...
March 1, 2018: Biointerphases
Anja Henss, Svenja-K Otto, Kaija Schaepe, Linda Pauksch, Katrin S Lips, Marcus Rohnke
Within this study, the authors use human mesenchymal stem cells incubated with silver nanoparticles (AgNPs) as a model system to systematically investigate the advantages and drawbacks of the fast imaging delayed extraction mode for two-dimensional and three-dimensional (3D) analyses at the cellular level. The authors compare the delayed extraction mode with commonly employed measurement modes in terms of mass and lateral resolution, intensity, and dose density. Using the delayed extraction mode for single cell analysis, a high mass resolution up to 4000 at m/z = 184...
February 28, 2018: Biointerphases
Corryn E Chini, Gregory L Fisher, Ben Johnson, Michael M Tamkun, Mary L Kraft
Advances in three-dimensional secondary ion mass spectrometry (SIMS) imaging have enabled visualizing the subcellular distributions of various lipid species within individual cells. However, the difficulty of locating organelles using SIMS limits efforts to study their lipid compositions. Here, the authors have assessed whether endoplasmic reticulum (ER)-Tracker Blue White DPX® , which is a commercially available stain for visualizing the endoplasmic reticulum using fluorescence microscopy, produces distinctive ions that can be used to locate the endoplasmic reticulum using SIMS...
February 26, 2018: Biointerphases
Katherine E Marusak, Julia R Krug, Yaying Feng, Yangxiaolu Cao, Lingchong You, Stefan Zauscher
The emerging field of biofabrication capitalizes on nature's ability to create materials with a wide range of well-defined physical and electronic properties. Particularly, there is a current push to utilize programmed, self-organization of living cells for material fabrication. However, much research is still necessary at the interface of synthetic biology and materials engineering to make biofabrication a viable technique to develop functional devices. Here, the authors exploit the ability of Escherichia coli to contribute to material fabrication by designing and optimizing growth platforms to direct inorganic nanoparticle (NP) synthesis, specifically cadmium sulfide (CdS) NPs, onto porous polycarbonate membranes...
February 9, 2018: Biointerphases
Jonas K Hannestad, Fredrik Höök, Peter Sjövall
The organization of lipid membranes plays an important role in a wide range of biological processes at different length scales. Herein, the authors present a procedure based on time-of-flight secondary ion mass spectrometry (ToF-SIMS) to characterize the nanometer-scale ordering of lipids in lipid membrane structures on surfaces. While ToF-SIMS is a powerful tool for label-free analysis of lipid-containing samples, its limited spatial resolution prevents in-depth knowledge of how lipid properties affect the molecular assembly of the membrane...
February 8, 2018: Biointerphases
Martin Körsgen, Bonnie J Tyler, Marcel Heeger, Moritz Buhl, Heinrich F Arlinghaus
The use of time-of-flight secondary ion mass spectrometry (SIMS) is of increasing interest for biological and medical applications due to its ability to provide chemical information on a submicrometer scale. However, the detection of larger biomolecules such as phospholipids and peptides is often inhibited by high fragmentation rates and low ionization efficiencies. One way to increase the secondary ion molecular yield is to chemically modify the surface using the matrix-enhanced SIMS approach, where an organic matrix is placed upon the surface...
February 8, 2018: Biointerphases
David M Carr, Ashley A Ellsworth, Gregory L Fisher, Wescley W Valeriano, Juan P Vasco, Paulo S S Guimarães, Rodrigo R de Andrade, Elizabeth R da Silva, Wagner N Rodrigues
The iridescent wings of the Chalcopterix rutilans damselfly (Rambur) (Odonata, Polythoridae) are investigated with focused ion beam/scanning electron microscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. The electron microscopy images reveal a natural photonic crystal as the source of the varying colors. The photonic crystal has a consistent number and thickness (∼195 nm) of the repeat units on the ventral side of the wing, which is consistent with the red color visible from the bottom side of the wing in all regions...
February 5, 2018: Biointerphases
Vânia Vilas-Boas, Begoña Espiña, Yury V Kolen'ko, Manuel Bañobre-Lopez, José A Duarte, Verónica C Martins, Dmitri Y Petrovykh, Paulo P Freitas, Felix D Carvalho
The use of targeted nanoparticles for magnetic hyperthermia (MHT) increases MHT selectivity, but often at the expense of its effectiveness. Consequently, targeted MHT is typically used in combination with other treatment modalities. This work describes an implementation of a highly effective monotherapeutic in vitro MHT treatment based on two populations of magnetic particles. Cells were sequentially incubated with two populations of magnetic particles: nonfunctionalized superparamagnetic nanoparticles and anti-CXCR4-functionalized particles...
February 5, 2018: Biointerphases
André Portz, Satoka Aoyagi, Michael Dürr
Mixed peptide/lipid samples were analyzed with respect to their chemical composition by means of desorption/ionization induced by neutral SO2 clusters (DINeC) in combination with mass spectrometry (MS). Depth profiles of the mixed films indicated a segregation layer of lipid on top of all samples. The thickness of this layer as obtained by DINeC-MS was in the order of one nanometer what can be seen as an upper limit for the depth resolution of DINeC-MS. The relative amounts of the substance of peptide and lipid derived for the bulk material of mixed samples with different compositions were found to be close to the nominal values indicating a low matrix effect...
February 1, 2018: Biointerphases
Jungdae Park, Hee-Kyung Na, Hyun Kyong Shon, Hye Young Son, Yong-Min Huh, Sang-Won Lee, Tae Geol Lee
The development of analytical tools for accurate and sensitive detection of intracellular metabolites associated with mutated metabolic enzymes is important in cancer diagnosis and staging. The gene encoding the metabolic enzyme isocitrate dehydrogenase 1 (IDH1) is mutated in various cancers, and mutant IDH1 could represent a good biomarker and potent target for cancer therapy. Owing to a mutation in an important arginine residue in the catalytic pocket, mutant IDH1 catalyzes the production of 2-hydroxyglutarate (2-HG) instead of its wild type product α-ketoglutarate (α-KG), which is involved in multiple cellular pathways involving the hydroxylation of proteins, ribonucleic acid, and deoxyribose nucleic acid (DNA)...
January 30, 2018: Biointerphases
Klaus Liefeith, Marion Frant, Ute Müller, Per Stenstad, Heidi Johnsen, Ruth Schmid
The primary goal of our investigation was the development of a versatile immobilization matrix based on archaeal tetraether lipids that meets the most important prerequisites to render an implant surface bioactive by binding specific functional groups or functional polymers with the necessary flexibility and an optimal spatial arrangement to be bioavailable. From this point of view, it appears obvious that numerous efforts made recently to avoid initial bacterial adhesion on catheter surfaces as an important prerequisite of material associated infection episodes have shown only a limited efficiency since the bioactive entities could not be presented in an optimal conformation and a stable density...
January 30, 2018: Biointerphases
Shusuke Nakano, Takayuki Yamagishi, Satoka Aoyagi, André Portz, Michael Dürr, Hideo Iwai, Tomoko Kawashima
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is one of the most powerful methods to analyze biomolecules in biological tissues and cells because it provides detailed chemical structure information and chemical images with a high spatial resolution. However, in terms of quantitative analysis, there are issues such as matrix effects that often cause secondary ion intensity changes regardless of the actual concentration in a sample. For instance, the intensity of secondary ions related to peptides is generally suppressed when lipids coexist...
January 19, 2018: Biointerphases
Yaokun Pan, Chuanzhong Chen, Rui Feng, Hongwei Cui, Benkui Gong, Tingting Zheng, Yarou Ji
Magnesium alloys are potential biodegradable implants for biomedical applications, and calcium (Ca) is one kind of ideal element being examined for magnesium alloys and biodegradable ceramic coatings owing to its biocompatibility and mechanical suitability. In this study, microarc oxidation (MAO) coatings were prepared on Mg-xCa alloys to study the effect of Ca on the microstructure and corrosion resistance of Mg-xCa alloys and their surface MAO coatings. The electrochemical corrosion behavior was investigated using an electrochemical workstation, and the degradability and bioactivity were evaluated by soaking tests in simulated body fluid (SBF) solutions...
January 16, 2018: Biointerphases
Marwa Munem, Oscar Zaar, Kelly Dimovska Nilsson, Noora Neittaanmäki, John Paoli, John S Fletcher
A set of basal cell carcinoma samples, removed by Mohs micrographic surgery and pathologically identified as having an aggressive subtype, have been analyzed using time-of-flight secondary ion mass spectrometry (SIMS). The SIMS analysis employed a gas cluster ion beam (GCIB) to increase the sensitivity of the technique for the detection of intact lipid species. The GCIB also allowed these intact molecular signals to be maintained while surface contamination and delocalized chemicals were removed from the upper tissue surface...
January 12, 2018: Biointerphases
Lin Du, Xiaohui Yang, Wenqiang Li, Haoying Li, Shanbao Feng, Rong Zeng, Bin Yu, Liangxing Xiao, Yu Liu, Mei Tu, Heng-Yong Nie
As an antibiotic that prevents and treats infections caused by Gram-positive bacteria such as Staphylococcus aureus, vancomycin incorporated in a biodegradable polymer poly(lactide-co-glycolide) provides opportunities to construct controlled-release drug delivery systems. Developments associated with this promising system have been largely concentrated on areas of drug delivery kinetics and biodegradability. In order to provide surface analytical approaches to this important system, the authors demonstrate applicability of time-of-flight secondary ion mass spectrometry (TOF-SIMS) in three-dimensional molecular imaging for a model system consisting of alternating layers of ploy(lactide-co-glycolide) and vancomycin...
January 10, 2018: Biointerphases
Patricia Losada-Pérez, Ozge Polat, Atul N Parikh, Erkin Seker, Frank Uwe Renner
Nanoporous gold (np-Au) is a nanostructured metal with many desirable attributes. Despite the growing number of applications of nanoporous materials, there are still open questions regarding their fabrication and subsequent surface functionalization. For example, the hydrophobic nature of gold surfaces makes the formation of planar supported lipid layers challenging. Here, the authors engineer the interface between np-Au and 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid layers using well-differentiated approaches based on vesicle adsorption and solvent exchange methods...
January 5, 2018: Biointerphases
Katharina Maniura-Weber, Stefan Zauscher, Sally McArthur
No abstract text is available yet for this article.
January 4, 2018: Biointerphases
Caitlyn M Gatley-Montross, John A Finlay, Nick Aldred, Harrison Cassady, Joel F Destino, Beatriz Orihuela, Michael A Hickner, Anthony S Clare, Daniel Rittschof, Eric R Holm, Michael R Detty
Multivariate analyses were used to investigate the influence of selected surface properties (Owens-Wendt surface energy and its dispersive and polar components, static water contact angle, conceptual sign of the surface charge, zeta potentials) on the attachment patterns of five biofouling organisms (Amphibalanus amphitrite, Amphibalanus improvisus, Bugula neritina, Ulva linza, and Navicula incerta) to better understand what surface properties drive attachment across multiple fouling organisms. A library of ten xerogel coatings and a glass standard provided a range of values for the selected surface properties to compare to biofouling attachment patterns...
December 29, 2017: Biointerphases
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