Download or read book Sensing and Characterizing Interactions with Lipid Membranes written by Simou Sun and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Herein, interactions between lipid membranes and physiologically important species, from divalent cations to viral proteins, are sensed and characterized in model membrane systems. By applying vibrational sum frequency generation spectroscopy (VSFS), we show that Ca2+, Mg2+ and Zn2+ bind to phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in different binding modes, which lead to distinct effects on lipid headgroup orientation and membrane chemical and physical properties. For example, Ca2+-PI(4,5)P2 interactions inhibit protein binding to the lipid, however, Mg2+ can hardly do so. Also, Zn2+ induces lipid domain formation and lipid monolayer phase transition more easily than both Ca2+ and Mg2+. Next, by means of pH modulation fluorescence sensing assay, we demonstrate that the commonly consumed small molecule drug, ibuprofen, interacts with the lipid membrane in three consecutive steps. In each step, the drug has distinct influence on the biophysical properties of the membrane. Further, the interactions between lipid membranes and antimicrobial peptides, viral proteins are studied with the sensing assay. We find that favorable like-charge pairing is formed between nonaarginine (R9) peptides. As such, R9 is able to bind to lipid membranes more strongly and cooperatively than nonalysine (K9), which explains at the molecular level why arginine-rich peptides are better antimicrobial agents than lysine-rich peptides. Also, we are able to identify a new phosphatidylinositide binding site on poliovirus 3C protein, which also acts as the viral RNA binding site. By correlating the fluorescence signal change in the pH modulation sensing assay with the change of membrane surface potential, a mathematic model was built to calculate the surface coverage of divalent cations when binding to negatively charged lipid membranes. As such, we can report accurate binding stoichiometry between Ca2+, Mg2+, Zn2+ and three different anionic lipids. Another aspect of this work is to understand the interactions between PI(4,5)P2 supported lipid bilayers (SLBs) and the solid support, as well as the interleaflet distribution of PI(4,5)P2s in the SLB. We developed a novel analytical assay to separate the two leaflets of a SLB at ambient condition. In this way, we characterized the time-dependent PI(4,5)P2 distribution in the SLBs by directly demonstrating defect-mediated PI(4,5)P2 flipping. Also, we reveal that the strong interaction between PI(4,5)P2 and the underlying glass substrate is due to water-mediated hydrogen bonding.

Download or read book Smart Membranes and Sensors written by Annarosa Gugliuzza and published by John Wiley & Sons. This book was released on 2014-09-19 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the reader to use synergistically the concepts of membranes and sensors materials. It contains insightful contributions from leading scientists working in both the fields. The focus is on the fabrication of smart membranes from sensor materials and related impact on many technologically sophisticated areas such as telemedicine, microfluidics, drug delivery targeting, (bio)separation, labs-on-a-chip, textiles, power storage and release, environment monitoring, agro-food safety, cosmetics, architecture, automotive and so on. This book covers various topics, including the choice of materials and techniques for assembling responsive membranes with ability to transport mass, energy and signals on demand; the reader will find through the book an extensive description of the best techniques used to monitor molecular scale events, which are regarded as responsible for the smartness of multifunctional objects and for the conversion of chemical signals into optical, electrical, thermal and mechanical responses. The reader is encouraged to use this cross-disciplinary discussion for his own research. Chemical, biological and physical concepts, expressed through the book, contribute to form a common language, which will allow the reader to discover causes for reflection and innovation, measuring how smart objects with desired properties can be tailored from exiting materials and used flexibly for different developed applications. Specifically: This book deals with materials smartness and suitable techniques to assemble and characterize them in sensor-like membranes. This book shows how ultra-smart functional devices can be accomplished by using traditional raw materials. This book describes particular key events, which control 'sense to react and adapt' mechanisms. The potential of sensor-like membranes in some key strategic fields is examined with particular emphasis on biomedicine, food and textiles markets. The benefits arising from the use of smart membranes are analysed in terms of life quality, safety, and innovation.

Download or read book Lipid Bilayers written by J. Katsaras and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides the reader with an up to date insight of the current state of the art in the field of lipid bilayer research and the important insights derived for the understanding of the complex and varied behaviour of biological membranes and its function.

Download or read book High resolution Characterization of Model Lipid Membranes and Their Interaction with Cholera Toxin written by Chad Edward Miller and published by . This book was released on 2005 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of the Behaviors of Amphiphilic Bacterial Signaling Molecules in Solution and at Interfaces of Soft Materials written by Curran Gregory Gahan and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The work reported in this thesis focuses broadly on characterizing and exploiting the behaviors of bacterial quorum sensing (QS) signals, inhibitors, and QS-controlled products in solution and at interfaces with synthetic soft materials. Particular emphasis is placed on (i) characterizing the self-assembly of amphiphilic QS signals in aqueous solution, (ii) characterizing interactions of QS signals and products with lipid membranes and (iii) the discovery of new QS inhibitors (QSIs) and the incorporation of QSIs into polymeric materials for potential wound-healing applications. The second chapter of this thesis characterizes the self-assembly of N-acyl homoserine lactones (AHLs), a class of amphiphilic and non-ionic QS signal used by gram-negative bacteria, in aqueous solution and demonstrates that these molecules can self-assemble into spherical micelles and small vesicles in ways that are dictated by the length of their aliphatic tails, a behavior that is consistent with those of other families of amphiphilic molecules. In the subsequent three chapters, it is demonstrated that AHLs can interact with model self-assembled lipid membranes in ways that lead to substantial membrane remodeling and the growth of extended tubules and hemispherical caps from the membranes. These studies further show that the remodeling observed is modulated by both AHL structure and membrane composition in a way that is at least partially related to the ability of an AHL to translocate across the lipid membrane. The fundamental understanding gained in these previous four chapters is then applied to provide a basis for the design of lipid vesicles that can detect and respond to communities of bacteria that are actively engaging in QS. We demonstrate that these responsive vesicles can also be used to perform high-throughput screens and identify new small-molecule inhibitors of QS in Staphylococcus aureus. Finally, hydrolytically degradable polymer microparticles loaded with potent synthetic inhibitors of S. aureus QS are investigated as a modular basis for potential anti-virulence approaches to control bacterial infection and wound healing in a murine dermonecrosis abscess model. The last two chapters of this thesis focus on using optical and electron microscopy to characterize two other soft materials platforms: multilayer assemblies of polymer capsules and lipid-protein aggregates.

Download or read book Lipid Bilayers written by T. Gutberlet and published by Springer Science & Business Media. This book was released on 2001 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: A general review of lipid bilayer structure and dynamics is given, including such current topics as the hydration of lipid bilayers, the superstructural behaviour of bilayers at different states of hydration and external conditions, the role and behaviour of lipid bilayers on fusion and rupture and the interaction of lipid bilayers with small organic molecules and additives and of protein lipid bilayer interactions. In addition, recent research on lipid interaction with proteins and other molecules in monolayers is reviewed, and the use of highly aligned samples under biologically relevant conditions and the benefits derived from such preparations are addressed. Finally, the latest approach in simulation of impurities within a lipid bilayer is introduced. This book will be a comprehensive review of the current state of biologically relevant model membrane systems which will become an indispensible reference for the "working biophysicist".

Download or read book Handbook of Lipid Membranes written by Cyrus R. Safinya and published by CRC Press. This book was released on 2021-09-14 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides a unique overview of lipid membrane fundamentals and applications. The fascinating world of lipids that harbor and govern so many biological functionalities are discussed within the context of membrane structures, interactions, and shape evolution. Beyond the fundamentals in lipid science, this handbook focuses on how scientists are building bioinspired biomimetic systems for applications in medicine, cosmetics, and nanotechnology. Key Features: Includes experimental and theoretical overviews on the role of lipids, with or without associated biomolecules, as structural components imparting distinct membrane shapes and intermembrane interactions Covers the mechanisms of lipid-membrane curvature, by peptide and protein binding, and the roles of signalling lipids and the cytoskeleton in plasma membrane shape evolution Covers advanced X-ray and force measurement techniques Discusses applications in biomedicine, cosmetics, and nanotechnology, including lipid vectors in nucleic acid, drug delivery in dermal applications, and lipid-based sensors and artificial biointerfaces Covers artificial membranes from block copolymers, synthetic copolypeptides, and recombinant proteins Includes an exciting section that explores the role of lipids in the origin of life in hydrothermal conditions This book is a highly informative companion for professionals in biophysics, biochemistry, physical chemistry, and material and pharmaceutical sciences and bioengineering.

Download or read book Characterizing Nanoparticle Interactions at the Cellular Membrane written by Arielle Christen Mensch and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the use of nanotechnology continues to rise, the release of engineered nanomaterials into the environment becomes inevitable. A need exists to understand the implications of engineered nanomaterials and to develop sustainable alternatives as adverse impacts are uncovered. In order to reduce any negative impacts of nanomaterials and exploit any beneficial impacts, the field of environmental nanotechnology must aim to understand the behavior of nanomaterials in complex environments through the use of [in situ] analytical methods and utilize model systems (both in terms of nanomaterials and organisms) to determine the chemical factors that drive nanoparticle behavior. The work presented here focuses on the cellular membrane, which is hypothesized to be the first point of contact between a nanomaterial and an organism. The characterization of different models cellular membranes and the characterization of nanoparticle interactions at these model membranes are presented. First, we investigated the impact of natural organic matter (NOM), which is found ubiquitously in the environment, on the interactions between polymer wrapped diamond nanoparticles (DNPs) and lipopolysaccharide-containing supported lipid bilayers, a model for Gram-negative bacteria cell membranes. To demonstrate the relevance of our model system we extended our study to include experiments using a Gram-negative bacterium, [Shewanella oneidensis] MR-1. We found that NOM impacted the hydrodynamic and electrokinetic properties of DNPs in a concentration dependent manner, which altered subsequent interactions with both model and actual biological membranes. Our results demonstrate that the effects of NOM coronas on nanoparticle properties and interactions with biological surfaces can depend on the relative amounts of NOM and nanoparticles. We then examined the impact of polymer wrapped quantum dots (QDs) on supported lipid bilayers containing important biomolecules found in the outer membrane of eukaryotic cells (cholesterol and sphingomyelin). We used [in situ] analytical methods to study these interactions in real time and found that the QDs caused structural changes to the bilayers studied. Quartz crystal microbalance with dissipation monitoring coupled with nanoplasmonic sensing revealed favorable interaction between the QDs and the bilayers. Increases in dissipation and apparent mass gains upon rinse suggested structural rearrangement was occurring. Time-lapsed atomic force microscopy confirmed this hypothesis and revealed the disappearance of phase-segregated domains upon interaction with the QDs. Our results demonstrate the importance of using complementary [in situ] analytical methods to understand the complex interactions that occur at the cellular membrane. We next demonstrate the powerful capabilities of atomic force microscopy for imaging and characterizing biological membranes. We investigate the impact of the substrate in the formation and characteristics of phase-segregated domains in supported lipid bilayers. We considered commonly used substrates in different analytical techniques (e.g., mica, silica, and glass). We discussed the importance of considering the substrate in drawing conclusions across different techniques. We also demonstrated the spatial and temporal correlation of atomic force and fluorescence microscopy. Finally, we extended our work using atomic force microscopy and developed a protocol to image and characterize the mechanical properties of fixed and live rainbow trout ([Oncorhynchus mykiss]) gill epithelial cells. We discussed various experimental variables such as instrumental parameters, type of AFM probe used, and the confluency of the cells on the substrate. We found that the ideal imaging conditions included using an AFM probe with a low spring constant and relatively dull tip, working with cells grown to ~75% confluency, and scanning at low speeds, high amplitudes, and minimal forces. We showed that fixed trout gill cells had an increased height and modulus value as compared to live cells. This work demonstrated the first example of AFM imaging and mechanical mapping on either fixed or live trout gill cells and set a protocol to examine the impacts of different stressors, such as nanomaterials, on trout gill cells.

Download or read book Characterization of Nanoparticle protein and lipid Interactions in Synthetic Membranes written by Amanda M. Rundle and published by . This book was released on 2016 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Introduction to Fluorescence Sensing written by Alexander P. Demchenko and published by Springer Science & Business Media. This book was released on 2008-12-21 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fluorescence sensing is a rapidly developing field of research and technology. Its target is nearly the whole world of natural and synthetic compounds being detected in different media including living bodies. The application area range from control of industrial processes to environment monitoring and clinical diagnostics. Among different detection methods fluorescence techniques are distinguished by ultimate sensitivity, high temporal and spatial resolution and versatility that allows not only remote detection of different targets but their imaging within the living cells. The basic mechanism of sensing is the transmission of the signal produced by molecular interaction with the target to fluorescent molecules, nanoparticles and nanocomposites with the detection by devices based on modern electronics and optics. In this interdisciplinary field of research and development the book is primarily intended to be a guide for students and young researchers. It is also addressed to professionals involved in active research and product development serving as a reference for the recent achievements. The users of these products will find description of principles that could allow proper selection of sensors for particular needs. Making a strong link between education, research and product development, this book discusses future directions.

Download or read book Characterizing Molecular Motion in Selected Lipid Bilayer Systems written by Kelly Greenough and published by . This book was released on 2007 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modified Tethered Bilayer Lipid Membranesfor Detection of Pathogenic Bacterial Toxinsand Characterization of Ion Channels written by Naing Tun Thet and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biophysical Characterization of Lipid protein and Lipid lipid Interactions in Model and Reconstituted Membranes Using Static and Real time X ray Diffraction and Fluorescence Quenching Techniques written by Martin Denis Caffrey and published by . This book was released on 1982 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nanobiotechnology of Biomimetic Membranes written by Donald Martin and published by Springer Science & Business Media. This book was released on 2007-12-26 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the current state of research and development in biomimetic membranes for nanobiotechnology applications. It takes an international perspective on the issue of developing biotechnology applications from an understanding of the biomimetic membrane at the nanoscale. The success of these applications relies on a good understanding of the interaction and incorporation of macromolecules in membranes and the fundamental properties of the membrane itself.

Download or read book Chemical Tools to Characterize Membrane protein Binding Interactions Using Synthetic Lipid Probes written by Meng Meng Rowland and published by . This book was released on 2011 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Signaling lipids such as diacylglycerol (DAG) and the phosphatidylinositol polyphosphates (PIPn̳s) play crucial roles in numerous cellular pathways. However, characterization of their activities is hindered by the complexity of associated signaling pathways and of the membrane environment. To address this issue, we have developed lipid probes that are effective for characterizing biological events using different applications, including activity-based probing (PIPn̳s and DAG) and microarray analysis (PIPn̳s). The activity-based probes have been applied to label receptor targets in multiple cancer cell proteomes through photocrosslinking followed by click reactions. The probes were found to label several proteins, as judged by on-gel fluorescence, and labeling was abrogated through various controls, such as heat denaturation and competition. Proteomic studies have been successfully performed to identify protein targets through biotin enrichment followed by mass spectrometric analysis. For microarray analysis, functionalized PIPn̳ probes were synthesized and applied to develop a high throughput microarray analysis to measure protein-lipid binding affinity. These approaches will be invaluable for characterizing PIPn̳/DAG-regulated events and their involvement in disease. The design, synthesis and application of these lipid probes are included in this dissertation. In addition, the design and synthesis of other lipid probes are discussed, such as bis(monoacylglycero)phosphate (BMP), and lysophophatidylcholine (LPC) analogs.

Download or read book Lipid Domains written by and published by Academic Press. This book was released on 2015-06-08 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Current Topics in Membranes is targeted toward scientists and researchers in biochemistry and molecular and cellular biology, providing the necessary membrane research to assist them in discovering the current state of a particular field and in learning where that field is heading. This volume offers an up to date presentation of current knowledge in the field of Lipid Domains. - Written by leading experts - Contains original material, both textual and illustrative, that should become a very relevant reference material - The material is presented in a very comprehensive manner - Both researchers in the field and general readers should find relevant and up-to-date information

Download or read book Label Free Sensing on Supported Lipid Bilayers written by Aaron Douglas Robison and published by . This book was released on 2013 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cell membranes are integral for many biological processes. In addition to containing and protecting cellular contents and maintaining the chemical integrity of the cell, these interfaces host a variety of ligand-receptor interactions. These ligand-receptor interactions are important for cell signaling and transport and the ability to monitor them is key to understanding these processes. In addition, therapeutics and drug discovery is also aided by membrane-specific study, as the majority of drugs target receptors associated with the cell surface. The cell membrane can be effectively mimicked by the use of supported lipid bilayers, which provide a robust platform exhibiting the lateral fluidity and composition associated with cell membranes. The ability to study both ligand-receptor interactions as well as small molecule-membrane interactions on these model membranes is aided by the fact that these assays can be multiplexed and are amenable to use with low sample volumes with high throughput. Our laboratory has recently developed a strategy for fluorescent microscopy studies of ligand-receptor interactions on supported lipid bilayers without the use of fluorescently-labeled analytes. This technique involves the incorporation of pH-sensitive fluorophores into the composition of the supported lipid bilayer as embedded reporter dyes. It was determined that this assay can operate as either a "turn-on" or a "turn-off" sensor depending on the analyte to be detected. It was additionally found that modulating the ionic strength of the operating buffer allows for tuning the operating pH and sensitivity of the assay. This label-free technique can be utilized to monitor small peptide interactions with bilayers containing specific phospholipids. Basic amino acid sequences which are associated with transporting contents across membranes or anti-microbial activity can be monitored binding to negatively charged bilayers without the use of labels. Not only is this a sensitive technique for detecting small peptides, but thermodynamic data can be extracted as well. In a final set of experiments, the interaction of proteins with phosphatidylserine (PS) in supported lipid bilayers is observed by utilizing PS-Cu2+-induced quenching of fluorophores. Disruption of this metal-phospholipid, specifically by Ca2+-dependent protein kinases, results in a turn-on fluorescent assay, which can be used to monitor the binding of the protein to PS and the effects of other metal interference. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/148197