Molecular Assembly of Biomimetic Systems E-Book

Junbai Li

• Herausgeber: Wiley-VCH
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 350

Veröffentlichungsjahr: 2010

Beschreibung

Research on molecular assembly of biomimetic systems has evolved rapidly over the past years and the time is now ripe for a book that comprehensively summarizes both the fundamentals and recent developments with practical usage in mind. The proposed book covers fundamental and practical techniques of molecular assembly of biomimetic systems, for instance, layer-by-layer assembly, self-assembly, and microcontact printing. Biomimetic systems selected for inclusion in the book are mostly related to biological fields and make important contributions to biotechnology. The categories of assembled biomimetic systems include biomimetic membranes, biogenic microcapsules, molecular motors, biomimetic interfaces and biomimetic materials such as tubes, vesicles, fibers and ribbons. These assembled molecular mimetic systems are currently abundantly used in advanced fields of nanotechnology, biotechnology and materials science. The book also contains many recent examples and references in addition to describing the fundamental science. It will be useful for graduate students as well as researchers carrying out R&D in nanotechnology, biotechnology and material sciences.

Leseprobe

Table of Contents

Cover

Table of Contents

Halftitle page

Related Titles

Title page

Copyright page

Preface

Introduction

1 Biomimetic Membranes

1.1 Introduction

1.2 Lipid Monolayers

1.3 Modeling Membrane Hydrolysis In Vitro

1.4 Polyelectrolyte-Supported Lipid Bilayers

1.5 Conclusions and Perspectives

2 Layer-by-Layer Assembly of Biomimetic Microcapsules

2.1 Introduction

2.2 Layer-by-layer Assembly of Polyelectrolyte Multilayer Microcapsules

2.3 Biointerfacing Polyelectrolyte Microcapsules – A Multifunctional Cargo System

2.4 Application of Biomimetic Microcapsules

2.5 Conclusions and Perspectives

3 FoF1-ATP Synthase-Based Active Biomimetic Systems

3.1 Introduction

3.2 FoF1-ATPase – A Rotary Molecular Motor

3.3 Reconstitution of FoF1-ATPase in Cellular Mimic Structures

3.4 Conclusions and Perspectives

4 Kinesin–Microtubule-Driven Active Biomimetic Systems

4.1 Introduction

4.2 Kinesin–Microtubule Active Transport Systems

4.3 Active Biomimetic Systems Based on the Kinesin–Microtubule Complex

4.4 Layer-by-Layer Assembled Capsules as Cargo – A Promising Biomimetic System

4.5 Conclusions and Perspectives

5 Biomimetic Interface

5.1 Introduction

5.2 Preparation and Characterization of Biomolecule Patterning

5.3 Polymer Brush Patterns for Biomedical Application

5.4 Conclusions and Perspectives

6 Peptide-Based Biomimetic Materials

6.1 Introduction

6.2 Peptides as Building Blocks for the Bottom-up Fabrication of Various Nanostructures

6.3 Peptide–Inorganic Hybrids

6.4 Applications of Peptide Biomimetic Nanomaterials

6.5 Conclusions and Perspectives

Glossary

Index

Junbai Li, Qiang He, and Xuehai Yan

Molecular Assembly of Biomimetic Systems

Related Titles

Öchsner, A., Ahmed, W. (eds.)

Biomechanics of Hard Tissues

Modeling, Testing, and Materials

2010

ISBN: 978-3-527-32431-6

Kumar, C. S. S. R. (ed.)

Biomimetic and Bioinspired Nanomaterials

Series: Nanomaterials for the Life Sciences (Volume 7)

2010

ISBN: 978-3-527-32167-4

The Authors

Prof. Dr. Junbai Li

Chinese Academy of Sciences

Institute of Chemistry

Zhongguancun North 1st Str. 2

Beijing 100080

People’s Republic of China

Dr. Qiang He

Chinese Academy of Sciences

Institute of Chemistry

Zhongguancun North 1st Str. 2

Beijing 100080

People’s Republic of China

Dr. Xuehai Yan

Chinese Academy of Sciences

Institute of Chemistry

Zhongguancun North 1st Str. 2

Beijing 100080

People’s Republic of China

All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.: applied for

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

Bibliographic information published by

the Deutsche Nationalbibliothek

The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2011 Wiley-VCH Verlag & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Cover Design Formgeber, Eppelheim

ISBN: 978-3-527-32542-9

ISBN: 978-3-527-63414-9 (ebk)

Preface

We are frequently asked how much we can learn from nature. In most case, we can get the answers by biomimetics. With the development of nanosciences, biomimetics is staring at the molecular level. This is based on the fact that many bioactive molecules like DNA, lipid, peptide, proteins can self-assemble into well-defined structures and further to a supramolecular architecture while combining with other organic, inorganic or metal oxide compounds. It is therefore considered the promising method to fabricate novel materials. The obvious feature of such biomimetic systems are their artificial structures which can be inspired by biology. A major advantage of these assembled systems is that they keep their biochemical and physical parameters and properties in a controlled manner. Thus the intense interest in this field is clearly evident.

The present book attempts to introduce the aspects and practical techniques of molecular assembly of biomimetic systems, especially, the layer-by-layer assembly, self-assembly, microcontact printing, electron beam lithography and chemical lithography.

We have benefited from many efforts of our co-workers in making this book reality. We sincerely acknowledged them, notably Weixing Song, Zhihua An, Liqin Ge, Cheng Tao. We have to say that we have learned a lots about molecular assembly from Profs. H. Möhwald, H. Rinsdorf, T. Kunitake and Jiacong Shen who have done much of the pioneering work and we are grateful to all of them for their motivated and skillful helps and contributions.

Beijing, November 2010

Junbai Li

Qiang He

Xuehai Yan

Introduction

In nature, biological systems and physiological processes have evolved over millions of years to improve their properties and functions. Biomimetics, simply, is the attempt to mimic these properties and functions. It involves studying structures and mechanisms of tissue formation in the organisms. Using biology as a guide, we can now understand, engineer, and control bioactive molecular interactions, and assemble them into novel systems or materials. The molecular biomimetic approach opens up new avenues for the design and utilization of multifunctional molecular systems with a wide range of applications in nanotechnology and biotechnology. Molecular assembly of biomimetic systems is now regarded as one of the promising methods to fabricate well-defined nanostructures and materials, and its importance is now generally recognized.

Biomimetic systems are artificial structures that are inspired by biology. A major advantage of these systems is that both biochemical and physical parameters can be controlled precisely. Therefore, it is feasible to utilize biomimetic systems as experimental models for guiding research on biological mutation and evolution in organisms. Some bioactive molecules such as peptides, proteins, nucleic acids, and lipids can undergo self-assembly into well-defined structures similar to the assembly in living organs. Biomimetics is not limited to just copying nature because, with the development of modern biology, scientists can directly utilize biological units themselves to construct new types of systems sometimes as hybrid nanostructured materials. In this way, some of the manufacturing difficulties of biomimetics can be avoided. As will be illustrated in this book, natural molecular machines such as motor proteins are integrated into the engineering of active biomimetic systems so that new functionalized systems can be constructed.

This book covers fundamental aspects and practical techniques of the molecular assembly of biomimetic systems; in particular, layer-by-layer (LbL) assembly, self-assembly, microcontact printing, electron beam lithography (EBL), and chemical nanolithography. It also presents an overview of the molecular assembly of biomimetic systems that consists of the following six topics covered in individual chapters.

Biomimetic Membranes

Biological membranes are key components in biological systems, forming the natural boundary of cells to separate inner components from outer environment. A number of cell actions and functions relevant to the environment are fulfilled via membrane processes, in most cases depending on the interactions of membrane proteins and carbohydrates. Owing to the complexity of biological membranes, it is very important to design and engineer artificial model membranes to overcome the difficulty of investigating membrane function directly in living cells. In this regard, biomimetic membranes as either a lipid monolayer or lipid bilayers are created by simple artificial strategies, such as spread at air/water or oil/water interfaces, or vesicle fusion. A lipid monolayer fixed at the air/water interface is a popular model membrane for investigation of the hydrolysis process catalyzed by enzymes at the interface. More attention is being paid to lipid bilayers supported on a planar surface or a curved surface because supported membranes, especially cushioned by polymers, are an ideal model to unravel the physical and chemical properties of biomembranes and their contribution to membrane functions.

In Chapter 1, we primarily focus on the fabrication of a lipid monolayer as a simplified model for studying the dynamic adsorption and interfacial behavior as well as membrane hydrolysis process catalyzed by enzymes at the interface. In addition, we briefly summarize the most recent developments and applications on supported lipid bilayers at polyelectrolyte multilayers, including at planar and curved surfaces. The introduction of such a biomimetic membrane will enhance greatly our understanding of the function and property of biological membranes, and will also significantly help to develop advanced characterization tools or techniques for a better understanding of the biological membrane system.

Layer-by-Layer Assembly of Biomimetic Microcapsules

Biomimetic microcapsules are a class of artificial hollow sacs with controllable size and versatile function such as tunable physicochemical properties and permeability. They can be regarded as a promising cell mimic to simulate some functions of cell membranes. Quite different from conventional liposomes, such a biomimetic hollow sac contains a large enough compartment so that the natural environment of membrane-bound proteins can be recreated. The materials making up microcapsules are a variety of polymers that are beneficial for the affinity and embedment of membrane proteins on supported biological membranes. The LbL assembly technique, which was first developed by Decher for the fabrication of ultrathin multilayers, is effective in the preparation of a hollow shell upon colloidal templates. Biogenic microcapsules prepared by the LbL technique are of great interest due to their potential application in medicine, catalysis, cosmetics, and biotechnology. By the conversion of liposomes into lipid bilayers, the coating of active lipid bilayers on polymer microcapsules can readily be achieved. Such lipid-decorated microcapsules can serve as an ideal supported biomimetic membrane system to mimic functions of the cell membrane. This new hybrid system also enables the design and application of new biomimetic structured materials.

In Chapter 2, we describe how LbL-assembled polyelectrolyte microcapsules can be interfaced with biological components such as phospholipid membranes and proteins. LbL assembly has attracted extensive attention for the fabrication of biomimetic microcapsules because it provides engineered features including size, shape, thickness, composition and permeation, and the capability of incorporating different types of biomolecules. The applications of these biomimetic microcapsules in drug delivery, biosensors, and hybrid nanodevices are also addressed.

FoF1-ATP Synthase-Based Active Biomimetic Systems

ATP synthase (ATPase) is one of the most popular molecular machines and has been extensively studied. It can act as a rotary motor in the design of novel nanodevices, continuously synthesizing ATP in the artificial environment. Production of ATP is one of the most important chemical reactions in living biology. With regard to the production of ATP, ATPase is the primary enzyme to catalyze the reaction where the generation of ATP from ADP and inorganic phosphate is performed upon the induction of proton gradients. The functionality of ATPase has attracted great interest over the last decade. Many potential applications have been suggested, from the generation of bioenergy to the fabrication of nanodevices. Lipid membranes have been widely used as models for biological membranes and ATPase is particularly selected as a model membrane protein, since it is a major ATP supplier in the cell. As a membrane-bound protein, ATPase can be reconstituted in vitro into liposomes via detergent mediation. Nevertheless, the limitations of the size and instability of the assembled liposome complexes result in difficulties in understanding and analyzing the system. Instead, lipid-coated polymer microcapsules exhibit extensive advantages as a biomimetic vehicle having a similar function to liposomes, but controllable in size and robust in structure.

In Chapter 3, we explore how biomimetics can be applied to engineering functional nanomaterials, particularly to assembling ATPase in artificial containers and mimetic cellular systems with cellular processes. Much effort has been focused on assembling ATPase in biomimetic systems so that a complex cellular process can be constructed in a controllable manner. Recently, LbL-assembled microcapsules have proven to be a suitable cellular mimetic structure and have been applied to engineering active biomimetic systems with cellular processes. An added benefit is that these assembled microcapsules can be used as bioenergy containers and thus supply ATP on demand.

Kinesin–Microtubule-Driven Active Biomimetic Systems

Linear motor proteins such as kinesin and myosin can transport cargoes inside cells with both spatial and temporal precision. These linear motor proteins provide the inspiration of the design and build-up of novel biomimetic functional nanomaterials. Kinesins are a family of proteins that can be divided into 14 classes based on sequence similarity and functional properties. Over the past decades, efforts to use linear motor proteins as nanoactuators have made rapid progress. In general, these motor proteins consume chemical energy to power the movement of targeted components into devices engineered at the micro- and nanoscale. The design of such hybrid nanodevices requires suitable synthetic environments and the identification of unique applications. Linear cytoskeletal kinesin motors have dominated the emerging field of protein-powered devices because they are relatively robust and readily available. Tubulin can be commercially purchased, while the motor proteins can be purified from cells or expressed in recombinant bacterial systems and harvested in large quantities.

In Chapter 4, the recent progress of assembling kinesin–microtubule–cargo systems in a synthetic environment is presented. In particular, we discuss the selection, loading, and unloading of cargoes, and also highlight our ongoing work – LbL-assembled microcapsules serving as cargoes driven by kinesin motors.

Biomimetic Interface

Biomimetic interface engineering modifies the interfaces between biological and nonbiological systems to gain valuable insight into the biological interactions at these interfaces. The main advantage of biomimetic interface strategies is the ability to influence biological interactions by modifying the interfaces, while still retaining the vital physical properties and to some extent improving the biocompatibility of the materials. A number of methods or techniques, including optical lithography, nanoimprint lithography, dip-pen nanolithography, and microcontact printing, are available for the engineering or patterning of interfaces. These biologically functionalized interfaces, generally as biomimetic interfaces, have a wide range of applications in biology and nanotechnology (e.g., for drug delivery, biosensors, biochips and medical implants, etc.).

In Chapter 5, we provide a brief overview of the advances in the application of microcontact printing for lipid micropatterning, and EBL for lipid nanopatterning and polymer gradient structures. In particular, a relatively new technique, chemical nanolithography, which is based on radiation-induced changes in organic self-assembled monolayers, is addressed.

Peptide-Based Biomimetic Materials

Self-assembly of biological building blocks has attracted increasing attention due to their versatility for bottom-up fabrication, biocompatibility, and biodegradability, with a wide range of application in biology and nanotechnology. Many biomolecules including peptides and proteins can interact and self-assemble into highly ordered supramolecular architectures with functionality. In the self-assembly process the precise control of supramolecular architectures is achieved through synergistic effects of some weak noncovalent interactions such as hydrogen bonds, electrostatic interactions, π–π stacking, hydrophobic forces, nonspecific Van der Waals forces, chiral dipole–dipole interactions, and so on. Although these forces are individually weak, when combined as a whole, they govern self-assembly of molecular building blocks into superior and ordered superstructures. Self-assembly is ubiquitous in nature. By learning from nature one can purposefully devise and synthesize artificial building blocks amenable to self-assembly into superstructures by cooperative interactions of weak noncovalent interactions. Notably, peptides composed of several to dozens of amino acids have been of great interest in the creation of biomimetic or bioinspired nanostructured materials owing to their structural simplicity and tunability, functional versatility, cost-effectiveness, and widespread applications.

In Chapter 6, we first focus on the fabrication of peptide-based nanostructural materials from synthetic building blocks such as lipopeptides, polypeptides, amphiphilic peptides and, particularly, diphenylalanine-based peptides derived from Alzheimer’s β-amyloid polypeptide. In addition, we present the experimental results and progress in the integration of peptide biomaterials with functional inorganic components for creating multifunctional materials. We then discuss the potential applications of such assembled peptide-based materials in biological and nonbiological areas, including tissue engineering, gene or drug delivery, bioimaging and biosensors, as well as functional templates for nanofabrication.