Microarray biosensors

Oh BK, Robbins ME, Nablo BJ, Schoenfisch MH. Miniaturized glucose biosensor modified with a nitric oxide-releasing xerogel microarray. Biosensors Bioelectronics 2005, 21, 749-757. 

With the increasing interest in and application of DNA and protein microarrays, biosensors, cell surface interactions, and biomedical implants, various systems and strategies for the immobilization and patterning of biomolecules have been developed and some have become well established. A wide diversity of chemical methods for biomolecule immobilization on inorganic substrates has been implemented by different research groups. Often, the choice of the method is a compromise between effectiveness, cost, and technology. In consideration of stability and durability of the attached biomolecules, certainly, the covalent attachment has to be preferred. 

There are hundreds if not thousands of miniaturized biosensors published in literature today. Thus, a selection of only a few of them for a brief description is a difficult task. While the biosensors described here are exceptional examples of miniaturized systems, there are many others that would have deserved a description as well, if the space had been available. A selection has been made to give an overview of interesting biosensors such as DNA microarrays, biosensors coupled with capillary electrophoresis (CE), cantilever-based biosensors, electrochemical systems, optical biosensors, and visions of a p.TAS. The examples are described only briefly, for a complete understanding of the work published, the reader is advised to refer to the original publication. Hopefully, this overview gives a grasp of the interesting biosensors developed in the new miniature world. 

Alexeev VL, Das S, Finegold DN, Asher SA (2004) Photonic crystal glucose-sensing material for noninvasive monitoring of glucose in tear fluid. Clin Chem 50(12) 2353-2360 Allcock HR, Phelps MVB, Barrett EW, Pishko MV, Koh WG (2006) Ultraviolet photolithographic development of polyphosphazene hydrogel microstructures for potential use in microarray biosensors. Chem Mater 18(3) 609-613... 

Lee, M., Walt, D. R. (2000). A fiber-optic microarray biosensor using aptamers as receptors. Anal Biochem 282, 142-146. 

Virus Nanoparticles for Signal Enhancement in Microarray Biosensors... 

Beusink JB, Lokate AMC, BesseUnk GAJ et al (2008) Angle-scanning SPR imaging for detection of biomolecular interactions on microarrays. Biosensors and Bioelectronics 23 839-844... 

Another interesting approach to fiber-optic sensor development has been reported by Walt and co-workers [114,115], who have created multiplexed extrinsicmode fiber optic microarray biosensor. The sensor employed fiber optic bundles (2-3 feet in length) composed of many optical fibers each 200-350 Lun in diameter. The microarray was fabricated by immobilizing a different oligonucleotide probe sequence onto the distal end of each fiber. Individual fibers within the bundle were made reactive for oligonucleotide immobilization by immersing the bundle in a solution of... 

Bioresorbable polymers, 3 735-740 Bioselective adsorption, 6 387 Biosensors, 3 794-815 14 154 22 269 affinity DNA biosensors, 3 805-808 affinity immunosensors, 3 800-805 applications, 3 812-813 biomimetic sensors, 3 809-810 catalytic, 3 796-799 cellulose ester applications, 5 408 comparison with microarrays, J6 38It evolution of, 16 380-381 production by thick-film technology, 3 810-812... 

These conditions are met in most practical situations, in micro- and even nanobiodevice applications. For instance, the high density of DNA molecules is required to increase the sensitivity of the device long DNA molecules are commonly (but not exclusively) used as target molecules in e.g., biosensors, microarrays and microPCR devices single DNA species used as targets translate in lack of complementarity and most substrates, (e.g., glass, polymers) for micro/nanobiodevices are amorphous. The critical difference between the self-assembled and amorphous DNA layers, which leads to the polymerlike character of the latter, is the lack of complementarity between adjacent strands. Still, as with polymers, the DNA chains have to have a consider-... 

A. Ferguson, T. C. Boles, C. P. Adams, and D. R. Walt. 1996. A Fiber Optic DNA Biosensor Microarray for the Analysis of Gene Expression. Nature Biotechnology 14 1681-1684. 

DNA biosensors based on electrochemical transduction of hybridization couple the high specificity of hybridization reactions with the excellent sensitivity and portability of electrochemical transducers. The ultimate goal of all researches is to design DNA biosensors for preparing a basis for the future DNA microarray system. 

Optical nucleic acid biosensors and microarrays based on fluorescence detection make use of fluorescent dyes to provide a measurable signal for target/probe hybridization. Ideally, fluorophores used for detecting nucleic acid hybridization should exhibit large molar absorptivity, resistance to pho-tobleaching, quantum yields that approach unity and the abibty to produce a resolvable signal at low concentrations both quickly and reproducibly [40]. 

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