Self-assembled Transmembrane Protein-polymer Conjugates for the Generation of Nano-thin Membranes and Micro-compartments PDF Download

Author: Himanshu Charan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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This project was focused on generating ultra thin stimuli responsive membranes with an embedded transmembrane protein to act as the pore. The membranes were formed by crosslinking of transmembrane protein polymer conjugates. The conjugates were self assembled on air water interface and the polymer chains crosslinked using a UV crosslinkable comonomer to engender the membrane. The protein used for the studies reported herein was one of the largest transmembrane channel proteins, ferric hydroxamate uptake protein component A (FhuA), found in the outer membrane of Escherichia coli (E. coli). The wild type protein and three genetic variants of FhuA were provided by the group of Prof. Schwaneberg in Aachen. The well known thermo responsive poly(N isopropylacrylamide) (PNIPAAm) and the pH and thermo responsive polymer poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) were conjugated to FhuA and the genetic variants via controlled radical polymerization (CRP) using grafting from technique. These polymers were chosen because they would...

Author: Shuhao Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages :

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This thesis covers the synthesis of conjugates of 2-Deoxy-D-ribose-5-phosphate aldolase (DERA) with suitable polymers and the subsequent immobilization of these conjugates in thin films via two different approaches. 2-Deoxy-D-ribose-5-phosphate aldolase (DERA) is a biocatalyst that is capable of converting acetaldehyde and a second aldehyde as acceptor into enantiomerically pure mono- and diyhydroxyaldehydes, which are important structural motifs in a number of pharmaceutically active compounds. Conjugation and immobilization renders the enzyme applicable for utilization in a continuously run biocatalytic process which avoids the common problem of product inhibition. Within this thesis, conjugates of DERA and poly(N-isopropylacrylamide) (PNIPAm) for immobilization via a self-assembly approach were synthesized and isolated, as well as conjugates with poly(N,N-dimethylacrylamide) (PDMAA) for a simplified and scalable spray-coating approach. For the DERA/PNIPAm-conjugates different synthesis routes were tested, including grafting-from and grafting-to, both being common methods for the conjugation. Furthermore, both lysines and cysteines were addressed for the conjugation in order to find optimum conjugation conditions. It turned out that conjugation via lysine causes severe activity loss as one lysine plays a key role in the catalyzing mechanism. [...]

Author: Gianfranco Pasut
Publisher: Elsevier
ISBN: 0444640827
Category : Technology & Engineering
Languages : en
Pages : 512

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Polymer–Protein Conjugates: From Pegylation and Beyond helps researchers by offering a unique reference and guide into this fascinating area. Sections cover the challenges surrounding the homogeneity of conjugates, their purity and polymer toxicity on long-term use, and how to deal with the risk of immunogenicity. These discussions help researchers design new projects by taking into account the latest innovations for safe and site selective polymer conjugation to proteins. PEG has been the gold standard and likely will play this role for many years, but alternatives are coming into the market, some of which have already been launched. After five decades of improvements, the ideas in this book are entering into a new era of innovation because of the advances in genetic engineering, biochemistry and a better understanding of the results from clinical use of PEG conjugates in humans. Provides an overview on the state-of-the-art of protein polymer conjugation Presents both the pros and cons of polymer-protein conjugates from the point-of-view of their clinical outcomes Outlines advantages and potential risks of present technology based on PEG Offers new alternatives for PEG and new approaches for on site-selective protein modification Identifies future direction of research in this field

Author: Chen Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 160

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Membrane separation is a field of both industrial and academic importance. Current technology is largely based on polymeric materials, and to a less extent other inorganic materials such as ceramics and metals. While developments in materials properties and membrane structures are constantly evolving, there are two challenges that need to be circumvented for better performance, i.e. the control over the pore structure and the chemical flexibility in modifying pore surface. "Bottom-up" approach to construct composite membranes using nanotubes in polymeric matrix is an effective route in fabricating membranes with well-defined architecture and tunable pore surface chemistry. This dissertation focuses on characterization and evaluation of cyclic peptide nanotubes (CPNs), a natural protein channel mimetic, in constructing sub-nanometer composite membranes with a cylinder-forming block copolymer (BCP) matrix in thin films. The fundamental understanding of the self-assembly of the CPNs from the building blocks establishes the foundation in utilizing the unique feature of CPNs to ensure precise structural control over the dimensions of the 1D nanotubes. The knowledge gained from the co-assembly of CPNs and BCP matrix in thin films allows further processing of the nanotubes to form well-aligned transport channels, establishing the guidelines in fabricating sub-nanometer porous membranes with and without surface chemistry modification. By identifying the key parameters in the membrane fabrication processes, design features for creating high-performance CPN based membranes can be determined and expanded. This indeed provides many exciting opportunities in developing new composite membranes with superior separation performances. The self-assembly of cyclic peptide (CP) subunits forming high aspect ratio nanotubes is driven by strong intermolecular hydrogen bonding. To modulate and tune the growth of CPNs, polymers are conjugated to the exterior of the peptide subunits, resulting in the formation of polymer covered-CPNs (pc-CPNs). Due to the restriction of intermolecular hydrogen bonding, the conjugated polymer chains enter a confined space set by the hydrogen bonding distance. The entropic penalty associated with deforming the conjugated polymers serves as an opposing force destabilizes nanotube structure, while the enthalpic hydrogen bonding drives the nanotube formation. A delicate balance between the enthalpic driving force and the entropic destabilizing force enables one to modulate the growth of the nanotubes. Thus, the dimensions of the resultant pc-CPNs can be supervised simply by regulating the extent of the entropic penalty from the conjugated polymer chains. In co-assembling CPNs and BCP matrix in thin films, both thermodynamic and kinetic parameters are critical to ensure homogeneous thin film morphology with well-aligned CPN channels at the center of the cylindrical microdomains of the BCP oriented normal to the substrate surface. The balance between the enthalpic interactions between the pc-CPNs and BCP and the entropic cost of polymer chain deformation gives rise to only one nanotube in the cylindrical microdomain. Due to the dynamic nature of CPN formation, preaggregation of the nanotubes causes defects of lay-down nanotubes at the membrane surface, hence compromising membrane quality and integrity. As a result, controlling the kinetic pathway of the co-assembly process is vital to fabricate high quality membranes for separation. Two simple approaches targeting two separate aggregation contributors have been developed to effectively prevent preaggregation of CPNs, resulting in high quality membranes suitable for molecular separation. With the advancement in incorporating functional groups to the constituting peptide subunits, the interior surface of the CPNs can be further functionalized. Membranes have been fabricated using both the unmodified and modified CPNs, in which gas separation of CO2/CH4 mixture and hydronium ion transport were performed. In general, the incorporation of the CPNs improves the overall performance of the membranes, likely by providing additional pathways for the permeating molecules. Differences in the separation behaviors of the regular CPNs and the methyl-modified CPNs are observed for both gas separation and hydronium ion transport, where higher selectivity for CO2 over CH4 is seen for the methyl-modified CPNs. The local dipole interactions with CO2 molecules as well as the reduction in pore size are speculated to induce the differences in the performances of unmodified and unmodified CPNs. These studies indeed establish the foundation in fabricating sub-nanometer porous membranes using self-assembled CPNs and BCP matrix in thin films. A delicate balance between the enthalpic and entropic contributions results in precise control over the structures of the nanotubes and the membranes. This unique "bottom-up" strategy demonstrates to be an effective platform in constructing new family of membranes for chemical separations.

Author: Aitziber L. Cortajarena
Publisher: Springer
ISBN: 3319391968
Category : Science
Languages : en
Pages : 286

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This book is devoted to the engineering of protein-based nanostructures and nanomaterials. One key challenge in nanobiotechnology is to be able to exploit the natural repertoire of protein structures and functions to build materials with defined properties at the nanoscale using “bottom-up” strategies. This book addresses in an integrated manner all the critical aspects that need to be understood and considered to design the next generation of nano-bio assemblies. The book covers first the fundamentals of the design and features of the protein building blocks and their self-assembly illustrating some of the most relevant examples of nanostructural design. Finally, the book contains a section dedicated to demonstrated applications of these novel bioinspired nanostructures in different fields from hybrid nanomaterials to regenerative medicine. This book provides a comprehensive updated review of this rapidly evolving field.

Author: Dan Liu
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Katsuhiko Ariga
Publisher: Elsevier
ISBN: 0323994733
Category : Technology & Engineering
Languages : en
Pages : 648

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Materials Nanoarchitectonics: From Integrated Molecular Systems to Advanced Devices provides the latest information on the design and molecular manipulation of self-organized hierarchically structured systems using tailor-made nanoscale materials as structural and functional units. The book is organized into three main sections that focus on molecular design of building blocks and hybrid materials, formation of nanostructures, and applications and devices. Bringing together emerging materials, synthetic aspects, nanostructure strategies, and applications, the book aims to support further progress, by offering different perspectives and a strong interdisciplinary approach to this rapidly growing area of innovation. This is an extremely valuable resource for researchers, advanced students, and scientists in industry, with an interest in nanoarchitectonics, nanostructures, and nanomaterials, or across the areas of nanotechnology, chemistry, surface science, polymer science, electrical engineering, physics, chemical engineering, and materials science. Offers a nanoarchitectonic perspective on emerging fields, such as metal-organic frameworks, porous polymer materials, or biomimetic nanostructures Discusses different approaches to utilizing "soft chemistry" as a source for hierarchically organized materials Offers an interdisciplinary approach to the design and construction of integrated chemical nano systems Discusses novel approaches towards the creation of complex multiscale architectures

Author: Jennifer J. McManus
Publisher: Humana
ISBN: 9781493996803
Category : Science
Languages : en
Pages : 266

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This volume explores experimental and computational approaches to measuring the most widely studied protein assemblies, including condensed liquid phases, aggregates, and crystals. The chapters in this book are organized into three parts: Part One looks at the techniques used to measure protein-protein interactions and equilibrium protein phases in dilute and concentrated protein solutions; Part Two describes methods to measure kinetics of aggregation and to characterize the assembled state; and Part Three details several different computational approaches that are currently used to help researchers understand protein self-assembly. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Thorough and cutting-edge, Protein Self-Assembly: Methods and Protocols is a valuable resource for researchers who are interested in learning more about this developing field.

Author: C.G. Gebelein
Publisher: Springer Science & Business Media
ISBN: 1461306574
Category : Science
Languages : en
Pages : 297

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The term biomimetic is comparatively new on the chemical scene, but the concept has been utilized by chemists for many years. Furthermore, the basic idea of making a synthetic material that can imitate the func tions of natural materials probably could be traced back into antiquity. From the dawn of creation, people have probably attempted to duplicate or modify the activities of the natural world. (One can even find allusions to these attempts in the Bible; e. g. , Genesis 30. ) The term "mimetic" means to imitate or mimic. The word "mimic" means to copy closely, or to imitate accurately. Biomimetic, which has not yet entered most dictionaries, means to imitate or mimic some specific bio logical function. Usually, the objective of biomimetics is to form some useful material without the need of utilizing living systems. In a simi lar manner, the term biomimetic polymers means creating synthetic poly mers which imitate the activity of natural bioactive polymers. This is a major advance in polymer chemistry because the natural bioactive polymers are the basis of life itself. Thus, biomimetic polymers imitate the life process in many ways. This present volume delineates some of the recent progress being made in this vast field of biomimetic polymers. Chemists have been making biomimetic polymers for more than fifty years, although this term wasn't used in the early investigations.

Author: John J. Kasianowicz
Publisher: Springer Science & Business Media
ISBN: 9781402006975
Category : Science
Languages : en
Pages : 46

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Polymers are essential to biology because they can have enough stable degrees of freedom to store the molecular code of heredity and to express the sequences needed to manufacture new molecules. Through these they perform or control virtually every function in life. Although some biopolymers are created and spend their entire career in the relatively large free space inside cells or organelles, many biopolymers must migrate through a narrow passageway to get to their targeted destination. This suggests the questions: How does confining a polymer affect its behavior and function? What does that tell us about the interactions between the monomers that comprise the polymer and the molecules that confine it? Can we design and build devices that mimic the functions of these nanoscale systems? The NATO Advanced Research Workshop brought together for four days in Bikal, Hungary over forty experts in experimental and theoretical biophysics, molecular biology, biophysical chemistry, and biochemistry interested in these questions. Their papers collected in this book provide insight on biological processes involving confinement and form a basis for new biotechnological applications using polymers. In his paper Edmund DiMarzio asks: What is so special about polymers? Why are polymers so prevalent in living things? The chemist says the reason is that a protein made of N amino acids can have any of 20 different kinds at each position along the chain, resulting in 20 N different polymers, and that the complexity of life lies in this variety.