Cell Surface Engineering: Fabrication of Functional Nanoshells: Volume 9 (Smart Materials Series) - Hardcover

Hardcover

ISBN 10: 1849739021 ISBN 13: 9781849739023

Publisher: Royal Society of Chemistry, 2014

Synopsis

A summary of the recent achievements in surface-functionalised cells including fabrication, characterisation, applications and nanotoxicity.

About this title

From the Back Cover

Cell surface engineering is an emerging field concerning cell surface modifications to enhance its functionalities. The book introduces the reader to the area of surface-functionalized cells and summarizes recent developments in the area including fabrication, characterization, applications and nanotoxicity.

Topics covered include recent approaches for the functionalization of cells with nanomaterials (polymer nanofilms and nanoparticles), fabrication of functional biomimetic devices and assemblies based on nanoparticle-modified microbial cells and artificial spores (the bioinspired encapsulation of living cells with inorganic nanoshells)

The book provides an interdisciplinary approach to the topic with authors from both biological and chemical backgrounds. This multidisciplinary view makes the book suitable for those interested in biomaterials, biochemistry, microbiology and colloid chemistry, providing both an introduction for postgraduate students as well as a comprehensive summary for those already working in the area.

Excerpt. © Reprinted by permission. All rights reserved.

Cell Surface Engineering

Fabrication of Functional Nanoshells

By Rawil F Fakhrullin, Insung S Choi, Yuri Lvov

The Royal Society of Chemistry

Copyright © 2014 The Royal Society of Chemistry
All rights reserved.

ISBN: 978-1-84973-902-3

Contents

Chapter 1 Introduction Rawil F. Fakhrullin, Yuri M. Lvov and Insung S. Choi, 1, 
Chapter 2 Functional Multilayered Polyelectrolyte Assemblies on Biological Cells Ben Wang, 4, 
Chapter 3 Direct Deposition of Nanomaterials onto Cells Alsu I. Zamaleeva, Renata T. Minullina, Joshua R. Tully, Maria R. Dzamukova, Svetlana A. Konnova and Ekaterina A. Naumenko, 28, 
Chapter 4 Bioinspired Encapsulation of Living Cells within Inorganic Nanoshells Ji Hun Park, Juno Lee, Beom Jin Kim and Sung Ho Yang, 48, 
Chapter 5 Characterization Techniques of Living Cells Encapsulated with Nanomaterials Mustafa Çulha, 80, 
Chapter 6 Cytocompatibility and Toxicity of Functional Coatings Engineered at Cell Surfaces Eugenia Kharlampieva and Veronika Kozlovskaya, 98, 
Chapter 7 Microelectronic Devices Based on Nanomaterial-Carrier Cells Vivek Maheshwari and Shehan Salgado, 126, 
Chapter 8 Artificial Spores Daewha Hong, Eun Hyea Ko and Insung S. Choi, 142, 
Chapter 9 Artificial Multicellular Assemblies from Cells Interfaced with Polymers and Nanomaterials Anupam A. K. Das, Rawil F. Fakhrullin and Vesselin N. Paunov, 162, 
Chapter 10 Magnetic Decoration and Labeling of Prokaryotic and Eukaryotic Cells Ivo Safarik, Zdenka Maderova, Kristyna Pospiskova, Katerina Horska and Mirka Safarikova, 185, 
Chapter 11 Cell Surface Engineering Using a Layer-by-Layer Nanofilm for Biomedical Applications Michiya Matsusaki and Mitsuru Akashi, 216, 
Chapter 12 Future of Cell Surface Engineering Rawil F. Fakhrullin, Yuri M. Lvov and Insung S. Choi, 240, 
Subject Index, 246, 

CHAPTER 1

Introduction

RAWIL F. FAKHRULLIN, YURI M. LVOV AND INSUNG S. CHOI

Bionanotechnology strives to fabricate functional biohybrid structures by synergistically combining biomacromolecules, cells, or multicellular assemblies with a wide range of nanomaterials, to which interesting functionalities are deliberately designed and introduced at the nanometer scale. The equipment of micrometer-sized cells with tiny devices, expanding the uses of the cells in biotechnology and biomedicine, also requires the nanoengineering of individual cells. Cells, having the typical sizes of dozens of micrometers, are relatively large if compared with nanometer-sized particles and films; therefore, the nanomodification of living cells opens new pathways to perform the selective control of cell properties. One can dream of designing a comfortable "smart dress" for cells, which protects the cells from hostile external environments and also provides useful toolkits that the cells may learn to use for their benefit. In addition to the application aspect, the "smart dress" coatings can be applied to the detailed investigation of fundamental biological properties, such as enzyme activity, membrane permeability, or viability preservation in cells, among many others.

The recent progress in bionanotechnology has been based extensively on inspiration from nature and adopted the mechanisms and structures found in living creatures for elaboration of man-made materials and devices. The cells are the biological units, which are used by nature to build all known living organisms, from micro-organisms to human beings. The complexity of cellular machinery, consisting of precisely orchestrated ensembles of enzymes, nucleic acids, and other biological macromolecules, is yet to be understood. However, each and every cell has a cellular membrane, acting as the thin barrier that protects the cell from the outer environments, ensures the internal integrity, and facilitates the controllable transport of the chemical species and particles. The cellular membranes are as diverse as the cells themselves, displaying a number of surface molecules, which can be used as a fingerprint profile of a certain biological species. Generally, they are built of membrane proteins, lipids and carbohydrates, complementing one another to support the shape, integrity and functionality of the cells. In addition to lipid bilayer membranes, some cells (i.e. most of bacteria, fungi, and plants) develop a thick protective coating, termed the cell wall, which reinforces the membranes and makes the cell-wall-protected cell rigid and resistant to external impacts. Other species rely solely on subtle cellular membranes, while sometimes employing exoskeleton-like structures like solid shells or building external skin-like structures. The enormous number of biological events is associated with the surfaces of membranes and cell walls, which are responsible for ion pumps, feeding, excretion, neuro-transmission, antibody/antigen recognition, cell division, etc. Virtually all of the cellular processes are controlled or regulated directly or indirectly by cellular surfaces that interface with the outer surroundings. Here, we regard all the cellular coatings as external cell surfaces, which exhibit certain surface chemistries. Like biological systems, any changes in cell-surface chemistry will inevitably lead to changes in cell functioning, and provide the cells with otherwise unavailable functionalities. Recent progresses allow for modification/functionalization of biological cells, viewed as colloid microparticles (albeit their very complex nature) in the first approximation, with the wide range of chemical techniques in a controllable fashion.

In this book, we define cell surface engineering as a chemical methodology aimed to deliberately modify, control, functionalize or alter the nanoscale surface chemistry of biological cells by the directed deposition of macro-molecules or nanomaterials as artificial shells on the nanometer scale. The ultimate goal of the cell surface engineering is to fabricate an artificial nanocoating on the cellular surfaces without modifying the genome of the cells by using purely chemical architecture approaches. The cell nanocoating generates various types of artificial cell-in-shell structures, where single isolated cells or cell aggregates are coated with either flexible or solid shells. These shells are typically fabricated to endow the cells with additional functionalities of interest. Alternatively, the cells can be used as mere sacrificial templates for fabrication of cell-mimicking hollow microcapsules or as parts of microelectronic devices. Historically, the layer-by-layer (LbL) deposition technique was used first to form nanolayers over sacrificial cells, but in the recent decade, a number of other approaches have emerged, offering new avenues in cell surface engineering.

We start this book with the introduction of three most popular approaches in cell surface engineering: 1) multilayered polyelectrolyte assemblies; 2) direct deposition of nanomaterials, and 3) bioinspired encapsulation with inorganic shells. These approaches have been successfully applied to fabricate nanocoatings on numerous representative model organisms. Next, the book reviews the experimental techniques to characterize and image the nanomaterial-encapsulated cells and to assess the viability and biological functionality of the surface-engineered cells. Then, we focus on applications of the nanocoated cells. The topics include the microelectronic devices fabricated with nanocoated cells including magnetically labeled prokaryotic and eukaryotic cells in analytical applications, and the LbL-coated cells in biomedical applications, such as tissue engineering and biosensors. Finally, the book covers the fabrication of artificial multicellular assemblies, where cells interfaced with polymers and nanomaterials are used as building blocks, and the formation of artificial spores mimicking bacterial endo-spores. These areas are truly multidisciplinary, utilizing the practical skills in nano- and colloidal sciences to chemically mimic and control biological processes, such as of evolution of multicellularity and cryptobiosis.

CHAPTER 2

Functional Multilayered Polyelectrolyte Assemblies on Biological Cells

BEN WANG

2.1 Layer-by-Layer (LbL) Polyelectrolyte Assembly

2.1.1 Self-Assembly and Emerging of LbL Polyelectrolyte Assembly

Nature exploits self-organization of multiple materials to produce biopolymer fibers, cell membranes, the flagellar motor, viruses, hard tissue and other multiple-scale organic–inorganic hybrid structures in many ways. Self-assembly is one of the forces behind the bottom-up construction of well-ordered structures at the nanometer scale. It typically occurs through reversible interactions that slowly arrange building blocks into the most thermodynamically favored structure, which is the fundamental process, and generates structural organization across scales. This process relies on molecular recognition between building blocks through noncovalent interactions, such as van der Waals and electrostatic forces, hydrogen bonding and π–π stacking, which provide the thermodynamic driving force to form, and determine the structure of highly ordered nanostructures.

In the second half of the 20th century, more and more attention was given to the design of thin solid films at the molecular level because of their potential applications in biology and medicine. The electrostatic attraction between oppositely charged molecules seemed to be a good candidate as a driving force for multilayer buildup, because it has the least steric demand of all chemical bonds. Based on the early pioneering work of Her in 1966, Decher and coworkers developed an approach to coat charged surfaces through LbL adsorption of chain-like molecules equipped with ionic groups at the end, polyelectrolytes, or other charged materials, such as nano-particles, from aqueous solution in the 1990s.

2.1.2 Physics and Molecular Properties of LbL Polyelectrolyte Assembly

Strong electrostatic attraction occurs between a charged surface and an oppositely charged molecule in solution. This phenomenon has long been known to be a factor in the adsorption of small organics and polyelectrolytes, but it has rarely been studied with respect to the molecular details of layer formation. In principle, the adsorption of molecules carrying more than one equal charge allows for charge reversal on the surface, which has two important consequences. One is that repulsion of equally charged molecules occurs, and thus self-regulation of the adsorption and restriction to a single layer. The other one is the ability of an oppositely charged molecule to be adsorbed in a second step on top of the first one. Cyclic repetition of both adsorption steps leads to the formation of multilayer structures.

A number of external parameters, which can be varied during the deposition process, are known to influence the resulting layer structure. These are the salt content of the deposition solutions, the concentration and charge density of the polyions (either varied by charge dilution in co-polymers or as a result of the pH in weak polyion solutions), the polyion rigidity, the molecular weight and also the surface charge density.

2.1.3 Types of LbL Assembly

Multiple electrostatic bonds causing a strong attraction are generally discussed as being responsible for the formation and stability of polyelectrolyte membranes. However, in order to explain the phenomenological behavior of layer formation, not only the Coulomb attraction, but additional contributions to the free energy of the complex have to be considered. Therefore, different kinds of LbL assembly can be classified based on this principle.

2.1.3.1 Conventional LbL Assembly

A solid substrate with a positively charged planar surface is immersed in a solution containing an anionic polyelectrolyte and a monolayer of the polyanion is adsorbed. This process of multilayer formation is based on the attraction of opposite charges, and thus requires a minimum of two oppositely charged molecules. Consequently, one is able to incorporate more than two molecules into the multilayer, simply by immersing the substrate in as many solutions of polyeletrolytes as desired, as long as the charge is reversed from layer to layer. Even aperiodic multilayer assemblies can easily be prepared.

2.1.3.2 Hydrogen-Bond-Mediated LbL Assembly

The concept of electrostatically driven assembly of multilayer structures allows for the incorporation of a wealth of different materials. However, polymers as multifunctional materials also offer the choice of building up layered structures through other types of interaction. One of the most commonly studied, nonelectrostatic interactions used in LbL assembly to date is hydrogen bonding. By exploiting this interaction, uncharged materials can be successfully incorporated into multilayer films. The pioneering studies in LbL multilayer assembly based on hydrogen bonding were reported independently by Stockton and Rubner, and Zhang's group in 1997. Stockton and Rubner investigated the use of polyaniline in alternation with a variety of water-soluble macromolecules, such as poly(vinyl-pyrrolidone) (PVPON), poly(vinyl alcohol) (PVA), polyacrylamide, and PEO, in which the oxygen atoms on the polymer backbone can be hydrogen-bonding acceptors, or poly(N-isopropylacrylamide), in which both an acceptor (carbonyl) and donor (amide) are present. Besides, film deposition is possible with polymer pairs containing side groups with carbazole and dinitrophenyl units that can form charge-transfer complexes.

2.1.3.3 Covalent Bonding Based LbL Assembly

Covalent bonds can be used to assemble LbL films having high stability due to the covalent bonds formed, and therefore these do not disassemble with changes in pH or ionic strength. Bergbreiter and coworkers performed the first example of sequential covalent assembly of polymers, using a co-polymer of maleic anhydride reacted in alternation with a polyamidoamine dendrimer. Blanchard and coworkers also investigated approaches to prepare multilayer films using a sequential covalent strategy.

Inspired by dopamine self-polymerizing at alkaline pH to form adherent polymer coatings on a large variety of substrates, synthetic polymers with catechol and amine functionalities may be useful as "universal" LbL primers. The synthetic catecholamine polymers adsorb to virtually all surfaces and can serve as a platform for LbL assembly in a surface-independent fashion. Besides, click chemistry refers to a set of covalent reactions with high reaction yields that can be performed under extremely mild conditions. This technique provides a simple and general method for the assembly of polyelectrolyte films of controlled thickness and that the click moiety provides stable crosslinks within the films.

2.1.3.4 Colloid-Involved LbL Assembly

The assembly of oppositely charged nanoparticles without polymers was first reported in 1966. The variety of inorganic shapes and compositions of the nanocomponents available for the LbL assembly process has led to an exceptional growth in the fabrication of LbL composites. Various assembly approaches have been employed to assemble polymers or nanoparticles in an ordered manner and to investigate the scope of potential applications. Polymers and inorganic nanocrystals have been studied in detail to create unique architectures inspired from Nature by manipulating the specific interactions. The LbL approach for assembling polymers with inorganic nanoparticles provides the opportunity to combine the electronic, optical, and magnetic properties of inorganic nanostructures with unique physical responses of macromolecules. For example, Rubner and coworkers used LbL assembly for oppositely charged nanoparticles without polymers, which exhibited antireflection, antifogging, and self-cleaning properties. LbL assembly of biomolecules with inorganic nanocomponents also leads to a new direction in the field of biomedical research, and the development of new technologies for diagnostic and therapeutic applications.

2.2 LbL Polyelectrolyte Assembly on Cells

2.2.1 Cell-Templated LbL Assembly for Polyelectrolyte Shell

Biological cells possess a wide variety of shapes and sizes, thus, using them as templates would allow the production of capsules with a wide range of morphologies. In the pioneering work on this topic, Escherichia coli (E. coli) and red blood cells (RBCs) are used as templates to produce hollow polyelectrolyte multilayered microcapsules consisting of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) (Figure 2.1).

This technique employs the step-wise self-assembly of polyelectrolyte multilayers on the biological templates with subsequent dissolution of the biological core, yields polyelectrolyte microcapsules of controlled size and shape that essentially replicate the morphology of original cells. The nature of the polyelectrolyte species, as well as solution properties and digestion procedures of the biological templates seem to influence the final properties of the microcapsule. Alternating adsorption of PAH and PSS onto charged latex particles always results in a reversal of the surface charge, independent of the layer number. However, alternating adsorption of the same polyelectrolytes onto the RBC surface produces a reversal of the surface potential only from the third layer onwards, with increasing potential differences up to the seventh layer. This difference is attributed to the more complex structure of a biological surface, where the negative surface charge is largely provided by sialic acid residues attached to glycoproteins. Hence, for biological particles, the surface charge is distributed nonhomogeneously in a layer of several nanometers thickness. Therefore, it is possible that the first layers of adsorbing polyelectrolytes do not fully compensate for this spatially distributed surface charge of the cell surface. The permeability of the polyelectrolyte microcapsules can be controlled by means of the outer milieu conditions and the polyelectrolyte species selected. Appropriate variation of these experimental parameters allows adjustment of the threshold for molecular permeability from a few Daltons up to more than tens of kDa or a pore size range of 0.1-15 nm. An additional advantage is the exceptional stability of the fabricated shells in various solvents, thereby offering the potential for stable micro- or even nanoemulsions, and the production of a new class of colloids with supermonodispersity and with a variety of shapes. Two interesting prospects for further development are the construction of polyelectrolyte microcapsules on biological cell templates other than RBC or E. coli, which could result in an extremely wide variety of geometric and physicochemical properties, and the functional properties, for example controllable permeability, of the shells templated on biological cells are also preserved.

(Continues...)

Excerpted from Cell Surface Engineering by Rawil F Fakhrullin, Insung S Choi, Yuri Lvov. Copyright © 2014 The Royal Society of Chemistry. Excerpted by permission of The Royal Society of Chemistry.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

Edition details

• Publisher: Royal Society of Chemistry
• Publication date: 2014
• Language: English
• ISBN 10: 1849739021
• ISBN 13: 9781849739023
• Binding: Hardcover
• Number of pages: 14
• Editor: Rawil F Fakhrullin