Bioelectronics: From Theory To Applications - Rilegato

Rilegato

ISBN 10: 3527306900 ISBN 13: 9783527306909

Casa editrice: Vch Verlagsgesellschaft Mbh, 2005

Riassunto

Im Laufe von Jahrmillionen brachte die Natur faszinierend komplexe biologische Strukturen hervor - eine nanotechnologische Schatzkammer, die Naturwissenschaft und Technik gerade erst zu erobern beginnen. Bio- und Immunosensoren, neuronale Rechner, biochemische "Fabriken" im Nanomaßstab gehören zu den viel versprechenden, zukunftsweisenden Anwendungsfeldern. Dieses Buch führt Naturwissenschaftler, Ingenieure und Studenten in das hochinteressante, interdisziplinäre Forschungsgebiet der Bioelektronik ein.

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Informazioni sull'autore

Itamar Willner is Professor of Chemistry at the Institute of Chemistry, The Hebrew University of Jerusalem, Israel. He graduated from the Hebrew University (1978), and after postdoctoral research at Berkley, he joined the faculty in Jerusalem in 1982. Prof. Willner is well known for his research in the areas of molecular electronics and optoelectronics, nanotechnology, bioelectronics, biosensors, optobioelectronics, nanobiotechnology, supramolecular chemistry, nanoscale chemistry and monolayer and thin-film assemblies. Prof. Willner holds the Israel Prize in Chemistry (2002), the Israel Chemical Society Award (2001) and the Max-Planck Research Award for International Cooperation (1998). He is a member of the Israel Academy of Sciences and Humanities and a member of the European Academy of Sciences.

Eugenii Katz is a Senior Research Associate at the Institute of Chemistry, The Hebrew University of Jerusalem, Israel. He completed his Ph.D. in 1983 at the Frumkin Institute of Electrochemistry, Moscow, and until 1991 acted as senior scientist at the Institute of Photosynthesis, Pushchino, Russia. In 1991 he performed postdoctoral research at The Hebrew University of Jerusalem and later, as a recipient of the Humboldt scholarship, he worked at the Technical University of Munich (1993). He joined the research group of I. Willner at the Hebrew University in 1994. Dr. Katz holds the Kaye Awards for Scientific Innovations (1995 and 2004). His research interests include electroanalytical chemistry, functionalized monolayers, functionalized nanoparticles, biosensors, biofuel cells and bioelectronics.

Dalla quarta di copertina

Medicine, chemistry, physics and engineering stand poised to benefit within the next few years from the ingenuity of complex biological structures invented and perfected by nature over millions of years. The combination of biological elements -- be it whole cells, single molecules or anything in between -- with the field of inorganic electronics yields a fascinating spectrum of opportunities and potential applications. Neurons, DNA strands, antigens, antibodies or enzymes connected to conventional circuitry are capable of turning biological activity into defined electrical signals which can be interpreted and acted upon, opening up such applications as bio- and immunosensors, neuronal or DNA computing, bioassays, or biochemical batteries. Similarly, sophisticated human/machine interfaces and ecologically benign harvesting of energy are equally attractive paths awaiting exploration. This book provides both researchers and engineers as well as students of all the natural sciences a vivid insight into the world of bioelectronics and nature's own nanotechnological treasure chamber.

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Bioelectronics

From Theory to ApplicationsBy Itamar Willner Eugenii Katz

John Wiley & Sons

Copyright © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
All right reserved.
ISBN: 978-3-527-30690-9

Chapter One

Bioelectronics-An Introduction

Itamar Willner and Eugenii Katz

The integration of biomolecules with electronic elements to yield functional devices attracts substantial research efforts because of thebasic fundamental scientific questions and the potential practical applications of the systems. The research field gained the buzzword "bioelectronics" aimed at highlighting that the world of electronics could be combined with biology and biotechnology. Mother Nature has in course of evolution processed the most effective catalysts (enzymes), and biomolecules of optimal recognition and binding capabilities that lead to highly selective and specific biopolymer complexes (antigen-antibody, hormone-receptor, or duplex DNA complexes). Similarly, biology provides the fastest and most complex computing and imaging systems where optical information is processed and stored in the form of three-dimensionalmemorable images (vision process). The tremendous biochemical and biotechnological progress in tailoring new biomaterials by genetic engineering or bioengineering provides unique and novel means to synthesize new enzymes and protein receptors, and to engineer monoclonal antibodies or aptamers for nonbiological substrates (such as explosives or pesticides) and DNA-based enzymes. All these materials provide a broad platform of functional units for their integration with electronic elements. The latter electronic elements may involve, for example, electrodes, field-effect transistor devices, piezoelectric crystal, magnetoresistance recording media, scanning tunneling microscopy (STM) tips and others. The bioelectronic devices, Figure 1.1, may operate in dual directions: In one configuration, the biological event alters the interfacial properties of the electronic element, thus enabling the readout of the bioreaction by monitoring the performance of the electronic unit such as the readout of the potential, impedance, charge transport, or surface resistance of electrodes or field-effect transistors, or by following the resonance frequencies of piezoelectric crystals. The second configuration of bioelectronic systems uses the electronic units to activate the biomaterials toward desired functions.

The major activities in the field of bioelectronics relate to the development of biosensors that transduce biorecognition or biocatalytic processes in the form of electronic signals. Other research efforts are directed at utilizing the biocatalytic electron transfer functions of enzymes to assemble biofuel cells that convert organic fuel substrates into electrical energy. Exciting opportunities exist in the electrical interfacing of neuronal networks with semiconductor microstructures. The excitation of ion conductance in neuronsmay be followed by electron conductance of semiconductor devices, thus opening the way to generating future neuron-semiconductor hybrid systems for dynamic memory and active learning. The recent progress in nanotechnology and specifically in nanobiotechnology adds new dimensions to the area of bioelectronics. Metal and semiconductor nanoparticles, nanorods, nanowires, and carbon nanotubes represent nano-objects with novel electronic properties. Recent studies revealed that the integration of these objects with biomolecules yields new functional systems that may yield miniaturized biosensors, mechanical devices and electronic circuitry.

A fundamental requirement of any bioelectronic system is the existence of electronic coupling and communication between the biomolecules and the electronic supports. Special methods to immobilize biomolecules on solid supports while preserving their bioactive structures were developed. Ingenious methods to structurally align and orient biomaterials on surfaces in order to optimize electronic communication were reported. Although impressive advances in the functional tailoring of biomolecule electronic units-hybrid systems were accomplished, challenging issues await scientific solutions. The miniaturization of the bioelectronic systems is a requisite for future implantable devices, and these types of applications will certainly introduce the need for biocompatibility of the systems. The miniaturization of the systems will also require the patterned, dense organization of biomolecules on electronic supports. Such organized systems may lead to high throughput parallel biosensing and to devices of operational complexity. The development of methods to address and trigger specific biomolecules in the predesigned arrays is, however, essential. This book attempts to highlight different theoretical and experimental topics that place bioelectronics as a modern interdisciplinary research field in science.

The understanding of charge transport phenomena through biological matrices attracted in the past decades, and continues to evolve, intensive theoretical and experimental work. The seminal contributions of the Marcus theory, the superexchange charge transfer theory, and the definition of superior tunneling paths in proteins had a tremendous impact on the understanding of biological processes such as the electron transfer in the photosynthetic reaction center, or the charge transport in redox-proteins that are the key reactions for numerous electrochemical and photoelectrochemical biosensing systems. A continuous feed back between elegant experimental work employing structurally engineered proteins and theoretical analysis of the results led to the formulation of a comprehensive paradigm for electron transport in proteins. This topic is addressed in detail in Chapter 2. The charge transport through DNA has recently been a serious scientific debate, and contradicting results claiming conductive, superconductive, semiconductive or insulating properties of DNA were reported. Theories describing charge transport through DNA (electrons or holes) that included hopping mechanisms, tunneling paths, or ion-assisted electron transfer were developed. Charge transport through DNA is anticipated to play a key role in the electrical detection of DNA and in the analysis of base mismatches in nucleic acids, in the use of DNA nanowires as circuitry in devices, and as a means to readout sequence specific DNA structures (DNA computers).

The electrical contacting between biomolecules and electrodes is an essential feature formost bioelectronic systems. Numerous redox enzymes exchange electronswith other biological components such as other redox-proteins, cofactors or molecular substrates. The exchange of electrons between the redox-centers of proteins and electrodes could activate the biocatalytic functions of these proteins, and may provide an important mechanism for numerous amperometric biosensors. Nonetheless, most of the proteins lack direct electron transfer communication with electrodes, and the lack of electrical communication between the biomaterials and the electronic elements presents one of the fundamental difficulties of bioelectronic systems. Although the barriers for charge transport between redox-proteins are easily explained by the Marcus theory and the spatial insulation of the redox-centers of enzymes by the protein matrices, they hinder the construction of electrically communicated biomolecular-electronic hybrid systems. Ingenious methods for the electrical contacting of biomolecular assemblies associated with electronic units were developed in recent years. The structural engineering of proteins with electron relays, the immobilization of redox enzymes in conductive polymers or redox-active polymers, the steric alignment of proteins on electron relays associated with electrodes, or the incorporation of redox-active intercalators in DNA represent a few means to electronically communicate the biomolecules with the electronic elements. These aspects are addressed in several sections of the book (Chapters 3 and 4) and are exemplified here with the electrical communication of redox enzymes with electrodes for the generation of amperometric biosensors and biofuel cells, and with the intercalation of a redox-label into double-stranded DNA for the electrical probing of DNA. The integration of glucose oxidase, which lacks direct electrical communication with electrodes, into a redox-active hydrogel film consisting of tethered Os(II)-polypyridine complex (1) units, and linked to the electrode, facilitates the electrical contact between the enzyme and the conductive support, Figure 1.2(A). The flexible redox-units linked to the polymer electrically wire the redox-center of the enzyme with the electrode by mediated electron transfer. Glucose sensing electrodes based on this charge transport concept are already on the market, and the design of microsized electrically wired enzyme electrodes for invasive continuous monitoring of glucose are close to commercial realization. A different application of electrically contacted enzyme electrodes rests in the design of biofuel cells, Figure 1.2(B). Fuel cell systems represent a well-established technology, where electrical power is generated by two complementary oxidation and reduction processes occurring at a catalytic anode and cathode, respectively. While the generation of electrical power by electrically contacted redox enzymes, in a biofuel cell configuration has probably little value in global energy production, the systems might have important merit as implantable devices that generate electrical power from body fluids. For example, a glucose-based biofuel cell utilizing electrically contacted enzyme electrodes could use blood as a fuel for the electrical powering of pace makers, insulin pumps or prosthetic elements.

The electrical contacting between molecular species and electrodes may be stimulated by specific biorecognition events. For example, the intercalation of doxorubicin (2) into the double-stranded DNA formed between a primer nucleic acid associated with an electrode and the complementary analyte DNA enables the electrochemical reduction of the intercalator and the subsequent catalytic reduction of [O.sub.2] to [H.sub.2][O.sub.2], Figure 1.3. The latter product induces in the presence of luminol and horseradish peroxidase (HRP) the formation of chemiluminescence as a readout signal for the DNA duplex formation on the electrode. The analysis of DNA by different electrochemical methods is discussed in Chapter 5.

Scanning probe microscopy techniques have introduced exciting opportunities in surface science and specifically in the characterization of biomolecules on surfaces. Scanning tunneling microscopy allows one to probe tunneling currents through proteins, thereby imaging the structure of individual protein molecules. Atomic force microscopy (AFM) not only permits the imaging of single biomolecules on surfaces but also permits the specific affinity interactions between complementary antigen-antibody pairs, or double-stranded DNA complexes to be followed. Scanning probe microscopes also add new dimensions as tools for patterning surfaces with biomolecules. The use of dip pen-lithography for the generation of biomolecular patterns, Figure 1.4(A) or the application of enzyme-functionalized AFM tips as a biocatalytic patterning tool, Figure 1.4(B), are just two examples demonstrating the potential of these nano-tools to fabricate dense biomolecular arrays. Realizing that bioelectronics involves the intimate coupling of biomolecules to electronic supports, the use of scanning probe microscopy to characterize the structure-function relationships of single biomolecules, and to actuate single biomolecules are inevitable for the future development of the field. Some aspects of scanning probe microscopy for bioelectronic applications and the manipulation of single biomolecules are addressed in Chapters 6 and 10.

Self-organization of biomolecules leads to unique 2D- and 3D-nanostructures that include structurally defined pores or channels. These materials may act as templates for the assembly of other materials, and the generation of systems of hierarchical structural complexity. Figure 1.5 shows a scanning force microscopy image of S-layer protein from Bacillus sphaericus on a silicon surface exhibiting square lattice symmetry with a lattice constant of 13.1 nm. Alternatively, the pore or channel structures may be utilized as "microreactors" of predefined dimensions for the synthesis of metallic or semiconductor nano-objects. This topic is addressed in Chapter 13, where the applications of S-layer proteins in bioelectronic systems are discussed.

Nanoparticles exhibit unique electronic, optical, catalytic and photoelectrochemical properties. The dimensions of nanoparticles are comparable to those of biomolecules such as enzymes, antigens/antibodies or DNA. Not surprisingly, the conjugation of biomolecules with metal and semiconductor nanoparticles yields hybrid systems of new electronic and optoelectronic properties. Indeed, tremendous progress was accomplished in the realization of biomolecule-nanoparticle hybrid systems for various bioelectronic applications. The electrical contacting of redox enzymes with electrodes by means of Au nanoparticles, the use of metal nanoparticle-nucleic acid conjugates for the catalytic deposition of metals and inducing electrical conductivity between electrodes, the electrochemical analysis of metal ions originating from the chemical dissolution of metallic or semiconductor nanoparticle labels associated with DNA, or the photoelectrochemical assay of enzyme reactions by means of semiconductor nanoparticles represent a few examples that highlight the potential of biomolecule-nanoparticle hybrid systems in biosensor design. Recent advances in the integration of biomolecules with semiconductors and the application of biomolecule-nanoparticle hybrids in bioelectronics are highlighted in Chapters 7 and 8, respectively. Several other applications of biomolecule-nanoparticle or biomolecule-carbon nanotube systems are also discussed in other sections of the book.

Exciting opportunities exist in the applications of biomolecules as templates for the synthesis of metallic or semiconductor nanowires. Such nanowires provide great promise for future nanocircuitry and for the assembly of nanodevices. The possibility of preparing DNA of desired shapes and base sequence, the availability of enzymes acting as biocatalytic tools for manipulating DNA, the binding of metal ions to the phosphate units of DNA chains, the specific intercalation of molecular components into the DNA biopolymers, and the specific DNA-protein interactions, turn DNA into an ideal matrix for its use as a template in the synthesis of nanowires consisting of metals or semiconductors. Indeed, tremendous progress has been accomplished by using DNA as a template for the generation of nanowires and patterned nanowires. This subject is highlighted in Chapter 9, which demonstrates the use of patterned Au nanowires on DNA as electrical contacts for the assembly of a nanotransistor. The construction of the biomolecule-base nanotransistor, Figure 1.6(A), is based on the assembly of a carbon nanotube between gold contacts formed on a DNA template using biorecognition events as driving motives for the construction of the nanodevice. Recent advances in this area suggest that self-assembled protein tubules or filaments may similarly be employed as templates for the synthesis of nanowire system. For example, Figure 1.6(B) depicts an impressive micrometer-long Ag wire exhibiting a width of ca 20 nm that was generated by the in situ reduction of silver ions in the template composed of aromatic short-chain peptides (diphenylalanine -amyloids), that are considered as key proteins in the development of Alzheimer's disease.

(Continues...)

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Dettagli dell'edizione

• Editore: Vch Verlagsgesellschaft Mbh
• Data di pubblicazione: 2005
• Lingua: Inglese
• ISBN 10: 3527306900
• ISBN 13: 9783527306909
• Rilegatura: Copertina rigida
• Numero edizione: 1
• Numero di pagine: 475
• Redattore: Willner Itamar, Katz Eugenii
• Contatto del produttore: non disponibile
• Persona responsabile: non disponibile