Read by QxMD icon Read


Manasi Chawathe, Atithi Patel, Sriramakamal Jonnalagadda, Alexander Sidorenko
Hybrid molecular brushes (HMBs) are macromolecules made of a linear backbone and polymeric side chains that differ in their chemical nature. The authors developed a new method of synthesis of HMB with chitosan (CHI) backbone. In the first step, chitosan-graft-polylactide (CHI-g-PLA) was synthesized by interfacial ring opening polymerization of lactide initiated from CHI. CHI-g-PLA is characterized for its molecular weight and structure. In the second step, polyvinylpyrrolidone (PNVP) or polyacrylamide (PAAm) is grafted by radical polymerization from the CHI in CHI-g-PLA to form CHI-g-PLA-g-PNVP and CHI-g-PLA-g-PAAm...
July 12, 2018: Biointerphases
Manuela S Killian, Adam J Taylor, David G Castner
Exposure of protein modified surfaces to air may be necessary in several applications. For example, air contact may be inevitable during the implantation of biomedical devices, for analysis of protein modified surfaces, or for sensor applications. Protein coatings are very sensitive to dehydration and can undergo significant and irreversible alterations of their conformations upon exposure to air. With the use of two compatible solutes from extremophilic bacteria, ectoine and hydroxyectoine, the authors were able to preserve the activity of dried protein monolayers for up to >24 h...
June 29, 2018: Biointerphases
Somayeh Ramezanian, Hien Xuan Ta, Balasingam Muhunthan, Nehal Abu-Lail
Biofilms in soil can offer solutions to many geotechnical problems. Controlling biofilm formation in soil requires a fundamental understanding of how bacterial cells interact with soil under relevant environmental conditions. Here, atomic force microscopy (AFM) was used to quantify the adhesion forces acting between a model soil microbe, Pseudomonas putida, and a model of quartz sand under a range of ionic strengths (ISs; 0.02M-0.52M) that bracket common environmental conditions present in soil. AFM forces were decoupled into specific and nonspecific components following the established Poisson statistical analysis method...
June 13, 2018: Biointerphases
Hongrui Zhang, Qi Gu, Gordon G Wallace, Michael J Higgins
Cell adhesion on conducting polymers is important in organic bioelectronics, including applications such as electronically switchable surfaces and electrochemical transistors. There is a fundamental interest in understanding the conducting polymer-cellular interface though as yet no direct measurements to quantify the cell adhesion forces and energies, particularly at the molecular level, have been undertaken. Here, the authors apply electrochemical-single cell force spectroscopy (EC-SCFS) to directly quantify the de-adhesion forces between single L929 fibroblast cells and polypyrrole doped with dodecylbenzene sulfonate (PPy-DBSA) under electrical stimulation...
June 11, 2018: Biointerphases
Sylvie Coscoy, Sarah Baiz, Jean Octon, Benoît Rhoné, Lucie Perquis, Qingzong Tseng, François Amblard, Vincent Semetey
Cells are able to develop various types of membrane protrusions that modulate their adhesive, migratory, or functional properties. However, their ability to form basal protrusions, particularly in the context of epithelial sheets, is not widely characterized. The authors built hexagonal lattices to probe systematically the microtopography-induced formation of epithelial cell protrusions. Lattices of hexagons of various sizes (from 1.5 to 19 μm) and 5-10 μm height were generated by two-photon photopolymerization in NOA61 or poly(ethylene glycol) diacrylate derivatives...
June 8, 2018: Biointerphases
Subramanian B, Thanka Rajan S, P J Martin, Vijay Vaithilingam, Penelope A Bean, Margaret D M Evans, A Bendavid
Diamond like carbon (DLC) films were deposited onto Ti6Al4V and Si wafer substrates by RF plasma enhanced chemical vapor deposition. The influence of dopants such as fluorine (F), silicon (Si), and nitrogen (N) on composition, structure, and biocompatibility was investigated. Ion scattering spectroscopy analysis revealed the presence of dopant atoms in the outer-most layers of the films. Raman studies showed that the position of the G-band shifts to higher frequencies with the fluorine and nitrogen content in the DLC film, whereas the incorporation of Si into DLC induces a decrease of the position of the G peak...
May 22, 2018: Biointerphases
Ulla König, Evmorfia Psarra, Olga Guskova, Eva Bittrich, Klaus-Jochen Eichhorn, Martin Müller, Petra B Welzel, Manfred Stamm, Petra Uhlmann
The development of bioengineered surface coatings with stimuli-responsive properties is beneficial for a number of biomedical applications. Environmentally responsive and switchable polymer brush systems have a great potential to create such smart biointerfaces. This study focuses on the bioconjugation of cell-instructive peptides, containing the arginine-glycine-aspartic acid tripeptide sequence (RGD motif), onto well-defined polymer brush films. Herein, the highly tailored end-grafted homo polymer brushes are either composed of the polyelectrolyte poly(acrylic) acid (PAA), providing the reactive carboxyl functionalities, or of the temperature-responsive poly(N-isopropylacrylamide) (PNIPAAm)...
May 18, 2018: Biointerphases
Mengli Zhao, Ye Cao, Huanhuan Gong, Yanqiu Sun, Jianhua Deng, Dejun Li, Rongxin Wan, Hanqing Gu
One of the key challenges in engineering tissues for cell-based therapies is developing biocompatible scaffold materials to direct cell behavior. In this paper, the cytocompatibilities of a flexible three-dimensional graphene scaffold (3D-G) and the same scaffold implanted with nitrogen ions (N+ /3D-G) are compared using an in vitro assay based on 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. The N+ /3D-G samples were prepared from low-temperature hydrothermally synthesized flexible 3D-G by ion implantation and were found to display improved adhesion and proliferation of rat osteoblast and mouse fibroblast cells...
May 16, 2018: Biointerphases
Jonas K Hannestad, Fredrik Höök, Peter Sjövall
No abstract text is available yet for this article.
May 8, 2018: Biointerphases
Siyu He, Hongyuan Li, Carmen L Gomes, Dmitri V Voronine
Optical detection and conformational mapping of aptamers are important for improving medical and biosensing technologies and for better understanding of biological processes at the molecular level. The authors investigate the vibrational signals of deoxyribonucleic acid aptamers specific to Listeria monocytogenes immobilized on gold substrates using tip-enhanced Raman scattering (TERS) spectroscopy and nanoscale imaging. The authors compare topographic and nano-optical signals and investigate the fluctuations of the position-dependent TERS spectra...
May 3, 2018: Biointerphases
Lorena M Cucci, Alessia Munzone, Irina Naletova, Antonio Magrì, Diego La Mendola, Cristina Satriano
Angiogenin is a protein crucial in angiogenesis, and it is overexpressed in many cancers and downregulated in neurodegenerative diseases, respectively. The protein interaction with actin, through the loop encompassing the 60-68 residues, is an essential step in the cellular cytoskeleton reorganization. This, in turn, influences the cell proliferation and migration processes. In this work, hybrid nanoassemblies of gold nanoparticles with angiogenin fragments containing the 60-68 sequence were prepared and characterized in their interaction with both model membranes of supported lipid bilayers (SLBs) and cellular membranes of cancer (neuroblastoma) and normal (fibroblasts) cell lines...
April 16, 2018: Biointerphases
Laetitia Bernard, Patrick Rupper, Greta Faccio, Dirk Hegemann, Olivier Scholder, Manfred Heuberger, Katharina Maniura-Weber, Marianne Vandenbossche
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is increasingly used for the detailed chemical characterization of complex organic materials. Of particular interest in biointerface materials, it provides the accurate molecular information on their surface, a prerequisite for the understanding of subsequent interaction with biomaterials. Plasma polymer films are promising biointerface materials, as tuning the deposition parameters allows the control over film stability and density of surface functional groups...
April 5, 2018: Biointerphases
Marco Werner, Thorsten Auth, Paul A Beales, Jean Baptiste Fleury, Fredrik Höök, Holger Kress, Reid C Van Lehn, Marcus Müller, Eugene P Petrov, Lev Sarkisov, Jens-Uwe Sommer, Vladimir A Baulin
Synthetic polymers, nanoparticles, and carbon-based materials have great potential in applications including drug delivery, gene transfection, in vitro and in vivo imaging, and the alteration of biological function. Nature and humans use different design strategies to create nanomaterials: biological objects have emerged from billions of years of evolution and from adaptation to their environment resulting in high levels of structural complexity; in contrast, synthetic nanomaterials result from minimalistic but controlled design options limited by the authors' current understanding of the biological world...
April 3, 2018: Biointerphases
Amy V Walker, Lev D Gelb, Grant E Barry, Polatip Subanajouy, Ananta Poudel, Manami Hara, Igor V Veryovkin, Graeme I Bell, Luke Hanley
Femtosecond laser desorption ionization mass spectrometry was used to obtain mass spectrometric (MS) images of lipids in human pancreatic tissue. The resulting MS images were analyzed using multivariate analysis, specifically principal component analysis and maximum a posteriori (MAP) reconstruction. Both analysis methods showed that the MS images can be separated into lipid and non-lipid areas. MAP analysis further indicated that the lipid areas are composed of phosphatidylcholines and fatty acids. However, definitive identification of the lipids cannot be made because none of the intact parent ions of phosphatidylcholine, sphingomyelins, and/or other lipids were observed...
April 2, 2018: Biointerphases
Minh Uyen Thi Le, Jin Gyeong Son, Hyun Kyoung Shon, Jeong Hyang Park, Sung Bae Lee, Tae Geol Lee
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging elucidates molecular distributions in tissue sections, providing useful information about the metabolic pathways linked to diseases. However, delocalization of the analytes and inadequate tissue adherence during sample preparation are among some of the unfortunate phenomena associated with this technique due to their role in the reduction of the quality, reliability, and spatial resolution of the ToF-SIMS images. For these reasons, ToF-SIMS imaging requires a more rigorous sample preparation method in order to preserve the natural state of the tissues...
March 30, 2018: Biointerphases
Michael J Taylor, Hannah Aitchison, Morgan J Hawker, Michelle N Mann, Ellen R Fisher, Daniel J Graham, Lara J Gamble
Biopolymers are used extensively in the manufacture of porous scaffolds for a variety of biological applications. The surfaces of these scaffolds are often modified to encourage specific interactions such as surface modification of scaffolds to prevent fouling or to promote a cell supportive environment for tissue engineering implants. However, few techniques can effectively characterize the uniformity of surface modifications in a porous scaffold. By filling the scaffold pores through polymer embedding, followed by analysis with imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS), the distribution and composition of surface chemical species though complex porous scaffolds can be characterized...
March 30, 2018: Biointerphases
Hatice Ceren Ates, Ebru Ozgur, Haluk Kulah
Methods for isolation and quantification of circulating tumor cells (CTCs) are attracting more attention every day, as the data for their unprecedented clinical utility continue to grow. However, the challenge is that CTCs are extremely rare (as low as 1 in a billion of blood cells) and a highly sensitive and specific technology is required to isolate CTCs from blood cells. Methods utilizing microfluidic systems for immunoaffinity-based CTC capture are preferred, especially when purity is the prime requirement...
March 23, 2018: Biointerphases
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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"