lab on a chip
DNA microarrays
DNA microarray is a multiplex technology used in molecular biology, medicine and bioscience. A
microarray an arrayed series of thousands of microscopic spots of DNA on a small piece of glass or silicon. These are commonly known as gene chips, biochips or "
lab on a chip".
A new two-volume book "Lab-on-a-Chip Technology" was published recently. The book describes the recent innovations in the microarray field and the applications in the fields of medicine, molecular biology, biotechnology and bioscience.
Lab-on-a-Chip Technology: Biomolecular Separation and Analysis ISBN: 978-1-904455-47-9
Lab-on-a-Chip Technology: Fabrication and Microfluidics ISBN: 978-1-904455-46-2
CURRENT BOOKS OF INTEREST
Metagenomics: Theory, Methods and ApplicationsAspergillus: Molecular Biology and GenomicsEnvironmental Molecular MicrobiologyNeisseria: Molecular Mechanisms of PathogenesisFrontiers in Dengue Virus ResearchABC Transporters in MicroorganismsPili and FlagellaLab-on-a-Chip Technology: Biomolecular Separation and AnalysisLab-on-a-Chip Technology: Fabrication and MicrofluidicsBacterial PolysaccharidesMicrobial ToxinsAcanthamoebaBacterial Secreted ProteinsLactobacillusMycobacteriumReal-Time PCRClostridiaPlant Pathogenic BacteriaBiopolymersPlasmidsPasteurellaceaeVibrio choleraePathogenic FungiHelicobacter pyloriCorynebacteriaStaphylococcusLeishmaniaArchaeaLegionellaRNA and the Regulation of Gene ExpressionMolecular Oral MicrobiologyLabels: biochip, DNA microarray, DNA microarrays, gene chip, lab on a chip, microarray
Potential of LOC
It is a challenge to fully describe the fast-moving field of
LOC. However, in a recent publication Herold and Rasooly (Eds) present descriptions of some of the many types of LOC, including fabrication and application details, and give the reader a sense of the range of LOC technologies and the enormous potential that these devices possess.
The main types and the critical elements of
LOC systems are discussed from both theoretical and experimental points of view, with special emphasis on technical and experimental detailed that may enable the reader to reproduce the LOC system described and conduct similar experiments. The huge range of applications in molecular biology and molecular diagnostics and testing are explored in depth.
from Herold and Rasooly (Eds)
in Lab-on-a-Chip TechnologyFurther reading:
Labels: lab on a chip, Lab-on-a-Chip Technology, LOC
LOC fabrication technologies
In general
LOC systems can be divided into three main categories based on materials and the fabrication technologies used for those materials: polymer systems, glass systems, and silicon systems. Silicon based LOC systems utilize fabrication techniques that grew out of integrated circuit (IC) fabrication technologies. Notable properties of silicon include its electrical conductivity and the wealth of techniques that have been developed for fabrication, surface treatment, and bonding.
Polymer based
LOC systems are a more recent development and there exist many fabrication methods, depending on the polymer used. PDMS (polydimethylsiloxane) is sold as a twocomponent liquid that hardens into a rubbery solid when mixed together. PDMS can be used with a surface patterned master to create half of an LOC device which is then completed by sealing the PDMS to a cover (e.g. to a glass slide). The surface patterned master can be micromanufactured from silicon or via soft lithography using a light sensitive mould material (e.g. SU-8). Many other manufacturing methods exist for polymers including embossing, lamination, injection moulding, laser machining, as well as all of the tradition direct machining methods (e.g. drilling or milling).
Glass-based
LOC system have the advantage that more is known about biochemical interactions with glass than with any other material. Many surface treatments exist for glass, and it has excellent thermal and optical properties. However, glass is more difficult to machine and designs based on glass need to adapt to the limited machining methods available.
from Herold and Rasooly (Eds)
in Lab-on-a-Chip Technology (Vol. 2)Further reading:
Labels: lab on a chip, Lab-on-a-Chip Technology, LOC
Liquid flow in LOC Systems
Liquid flow is an essential element of most
LOC systems. Liquid flow can be single-phase flow through microchannels or multi-phase flow of droplets on a surface. For single phase flow, the flow can be pressure driven, in which the pressure driving force is supplied by an external pump, or the fluid can be pumped by electroosmotic means where the motion of liquid is induced by an applied axial potential along a capillary tube or microchannel. Electroosmotic pumping depends on the electric double layer that forms in an electrolyte adjacent to a charged surface.
Alternately, individual droplets can be moved and manipulated on a surface (e.g. combined, separated or transported) by electric fields. Droplets form on a surface because the geometry of a droplet minimizes the energy of the system (including the energy of the liquid surface, exposed to the vapour phase, and the energy of the attraction between the liquid and the solid surface). Droplets can be manipulated on a surface in two different ways: 1) electrowetting, and 2) dielectrophoresis. Both of these techniques are actuated by manipulating electric fields around the droplets.
Electrowetting is based on the attractive forces between a solid surface and a liquid. When the attraction between the liquid and the solid surface is weak (hydrophobic for an aqueous system), then the droplet tends toward a spherical shape due to the dominance of surface tension energy. The surface force interaction with the fluid (i.e. the hydrophobicity) can be controlled by electric fields (electrowetting).
Dielectrophoresis requires alternating (AC) fields which induce a dipole in a discrete droplet. The droplet then experiences a net force due to the induced dipole when the frequency of the AC field is selected appropriately. Dielectrophoresis can be used to manipulate droplets on a surface using an array of surface electrodes, similar to that required for electrowetting.
from Herold and Rasooly (Eds)
in Lab-on-a-Chip Technology (Vol. 2)Further reading:
Labels: lab on a chip, Lab-on-a-Chip Technology, LOC
Miniaturization of LOC Systems
LOC systems can be miniaturized so that they can be integrated into various pieces of equipment in the medical, industrial, military and public safety fields. Miniaturization can enhance utility in many ways including allowing portability for field applications, providing multiple assays in one instrument (e.g. blood analyser for medical offices), and minimizing expensive reagents.
from Herold and Rasooly (Eds)
in Lab-on-a-Chip Technology (Vol. 2)Further reading:
Labels: lab on a chip, Lab-on-a-Chip Technology, LOC, miniaturization
LOC-based diagnostics
LOC-based diagnostics can be used for point of care testing where state-of-the-art molecular analysis is required without requiring a state-of-the-art laboratory. Diverse biomedical applications and biohazard detection can be carried out in the field. Biomedical applications include medical screening, testing and diagnostics at point of care by primary care providers. Biohazard detection, including pathogens and toxins, encompasses applications in food testing, public health, and biosecurity.
LOC systems can be used for a variety of analytical applications including DNA amplification and analysis, quantitative immunoassays, enzymatic activity assays and other analytical approaches which are done today mainly in centralized, dedicated laboratories with complex and expensive equipment by highly trained personnel. Rapid LOC analysis can provide immediate interactive information to health care providers that can be incorporated into the planning of patient care. LOC-based diagnostics have the potential to improve the rates of earlier detection of cancer and other diseases with attendant improved prognosis.
LOC technologies are projected to be extremely useful for enhancing health care delivery in the community setting and to underserved populations especially in remote areas.
from Herold and Rasooly (Eds)
in Lab-on-a-Chip Technology (Vol. 2)Further reading:
Labels: diagnostics, lab on a chip, Lab-on-a-Chip Technology, LOC, molecular diagnostics
LOC Systems
LOC systems have several potential advantages over other analytical approaches, especially the ability to perform complex analytical chemistry operations without a laboratory. This has the potential to allow samples to be analysed at the point of need rather than at a centralized laboratory.
Inherent advantages of LOC systems The laminar flow behaviour of liquids in typical miniaturized LOC systems allows better control of concentrations and other reaction conditions. Thus, it can reduce the time taken to synthesize and analyse samples, and improve the quality of the product. Miniaturized LOC systems typically require small reagent volumes which can reduce costs of testing and reduce the amount of chemical waste. Small sample sizes can also be a disadvantage because they may not always represent the average condition of a larger reservoir from which they are taken.
from Herold and Rasooly (Eds)
in Lab-on-a-Chip Technology (Vol. 2)Further reading:
Labels: lab on a chip, Lab-on-a-Chip Technology, LOC
In the early 1960s, several research groups started working on miniaturized silicon sensors. An early integrated
lab on a chip (LOC) device was a complete gas chromatograph on a single 'chip' developed at Stanford University and published in 1979. This new tool was 'expected to find application in the areas of portable ambient air quality monitors, implanted biological experiments, and planetary probes'. The expectations for LOC have been realized repeatedly in the laboratory and commercial applications are beginning to be realized (Herold and Rasooly 2009. Lab-on-a-Chip Technology. Caister Academic Press ISBN: 978-1-904455-47-9).
In the 1980s and 1990s the
LOC field moved rapidly and in the last decade approximately 3500 LOC related publications are indexed in Pubmed describing numerous fabrication methods and new applications using a broad array of technologies. The trend is towards more complex integrated multi-analyte LOC systems capable of more comprehensive analyses, utilizing advances in electronics and microfabrication that enable miniaturization and broader capabilities. The newest generation of LOC systems includes a miniaturized chip for isolation of rare circulating tumour cells in cancer patients and complex LOC devices utilizing valving technologies that provide dense fabrication and parallel pneumatic actuation of hundreds of valves.
Bibliography:
- Lab-on-a-Chip Technology: Fabrication and Microfluidics
- Lab-on-a-Chip Technology: Biomolecular Separation and Analysis
Labels: lab on a chip, Lab-on-a-Chip Technology, LOC
The term 'laboratory' can be defined as a facility which provides controlled conditions for scientific research, experiments or measurements. In recent years, many
lab-on-a-chip (LOC) devices, which provide controlled conditions for scientific measurements without a formal laboratory, have been developed and used in a wide array of biomedical and other analytical settings. LOC devices integrate and scale down laboratory functions and processes to a miniaturized chip format. In this context the term 'chip' is used loosely, unlike the 'traditional' silicon chip from electronics. LOC devices, or chips, can be fabricated from many types of material including various polymers (e.g. acrylic, polyester, and polycarbonate), glass, or silicon, as well as combinations of these materials (Herold and Rasooly 2009. Lab-on-a-Chip Technology. Caister Academic Press ISBN: 978-1-904455-47-9).
In this context the term 'chip' is used loosely, unlike the 'traditional' silicon chip from electronics. LOC devices, or chips, can be fabricated from many types of material including various polymers (e.g. acrylic, polyester, and polycarbonate), glass, or silicon, as well as combinations of these materials. Unlike the 'traditional' silicon integrated circuit (IC) fabrication technologies, a broad variety of fabrication technologies are used for LOC device fabrication.
Bibliography:
- Lab-on-a-Chip Technology: Fabrication and Microfluidics
- Lab-on-a-Chip Technology: Biomolecular Separation and Analysis
Labels: biochip, lab on a chip, LOC, microfluidics
Lab-on-a-chip
Lab-on-a-chip (LOC) devices integrate and scale down laboratory functions and processes to a miniaturized chip format. Many LOC devices are used in a wide array of biomedical and other analytical applications including rapid pathogen detection, clinical diagnosis, forensic science, electrophoresis, flow cytometry, blood chemistry analysis, protein and DNA analysis. LOC devices can be fabricated from many types of material including various polymers, glass, or silicon, or combinations of these materials. A broad variety of fabrication technologies are used for LOC device fabrication. LOC systems have several common features including microfluidics and sensing capabilities. Microfluidics deals with fluid flow in tiny channels using flow control devices (e.g. channels, pumps, mixers and valves). Sensing capabilities, usually optical or electrochemical sensors, can also be integrated into the chip (Herold and Rasooly 2009. Lab-on-a-Chip Technology. Caister Academic Press ISBN: 978-1-904455-47-9).
Lab-on-a-chip technology is a rapidly expanding area of science. It has applications in biotechnology, medicine, clinical diagnostics, chemical engineering, and pharmaceutics. As the lab-on-a-chip systems increase in importance and complexity it is important for scientists to become familiar not only with the technology but also with the potential applications.
Bibliography:
- Lab-on-a-Chip Technology: Fabrication and Microfluidics
- Lab-on-a-Chip Technology: Biomolecular Separation and Analysis
Labels: lab on a chip, LOC, microfluidics
Lab-on-a-Chip Technology: Biomolecular Separation and AnalysisPublisher: Caister Academic Press
Editor: Keith E. Herold and Avraham Rasooly
Publication date: August 2009
ISBN: 978-1-904455-47-9
A skillful selection of topics of exceptional importance to current science ensures that this book will be of major value to a wide range of molecular biologists, clinical scientists, microbiologists, biochemists and anyone interested in LOC technology or developing applications for LOC devices.
further informationLab-on-a-Chip Technology: Fabrication and MicrofluidicsPublisher: Caister Academic Press
Editor: Keith E. Herold and Avraham Rasooly
Publication date: August 2009
ISBN: 978-1-904455-46-2
This comprehensive volume presents the current technologies in the field and includes theoretical and technical information to enable both the understanding of the technology and the reproduction of experiments. The book aims to help the reader to understand current LOC technologies, to perform similar experiments, to design new LOC systems and to develop new methodologies and applications.
further informationReal-Time PCR: Current Technology and ApplicationsPublisher: Caister Academic Press
Editor: Julie Logan, Kirstin Edwards and Nick Saunders
Publication date: January 2009
ISBN: 978-1-904455-39-4
This essential manual presents a comprehensive guide to the most up-to-date technologies and applications as well as providing an overview of the theory of this increasingly important technique.
further informationMicrobial Production of Biopolymers and Polymer Precursors: Applications and PerspectivesPublisher: Caister Academic Press
Editor: Bernd H. A. Rehm
Publication date: January 2009
ISBN: 978-1-904455-36-3
Topics include the biochemistry and genetics of biosynthesis of xanthan, alginate, cellulose, cyanophycin, poly(gamma-glutamic acid), levan, hyaluronic acid, organic acids, oligosaccharides and polysaccharides, and polyhydroxyalkanoates. A recommended book for all biotechnology and microbiology laboratories.
further informationLabels: biopolymers, books, lab on a chip, LOC, microfluidics, PCR