Biochips detection technologies

Fluorescent detection technology applicable to biochips is evolving rapidly, resulting in detection instruments that are more powerful, user-friendly, and less expensive. Most systems employ photomultiplier tube (PMT) technology in conjunction with multiple colors, lasers, and a variety of filters. It is essentially a fluorescent microscope that... 

Abstract In this perspective article, we introduce a potentially transformative DNA/RNA detection technology that promises to replace DNA microarray and real-time PCR for field applications. It represents a new microfluidic technology that fully exploits the small spatial dimensions of a biochip and some new phenomena unique to the micro- and nanoscales. More specifically, it satisfies aU the requisites for portable on-field applications fast, small, sensitive, selective, robust, label- and reagent-free, economical to produce, and possibly PCR-free. We discuss the mechanisms behind the technology and introduce some preliminary designs, test results, and prototypes. 

Stafford, P. 2006. Genomics, Transcriptomics, and Proteomics Novel Detection Technologies and Drug Discovery. In Biochips as Pathways to Drug Discovery (eds Carmen, A. and Hardiman, G.), CRC Press, Boca Raton, pp. 321—338. 

Wright, G. L., Cazares, L. H., Leung, S.-M., Nasim, S., Adam, B.-L., Yip, T.-T., Schellhammer, P. F., Gong, L., and Vlahou, A. (2000). ProteinChip surface enhanced laser desorption/ionization (SELDI) mass spectrometry a novel protein biochip technology for detection of prostate cancer biomarkers in complex protein mixtures. Prostate Cancer and Prostatic Diseases 2, 264-276. 

DNA chips or biochips play an important role in the detection of various genes or analytes. Specific interactions between immobilized probes and analytes and the simultaneous detection of thousands of probes makes microarray technology an attractive analytical device. For example, the expressed genes of a whole genome that represents the temporary state of a cell can be detected in one hybridization experiment on a microarray. 

Figure 11.4. A spotted DNA array with two-color detection of hybridization. An example of a spotted DNA array (16 X 20 elements) is shown after hybridization with two differentially labeled cDNA preparations, Cy3 (pseudo-colored green) and Cy5 (pseudo-colored red). The overlaying of the green and red images produces the image shown. The hue of each spot, ranging from green to red, indicates the relative expression level for the gene specific for each spot (image courtesy Packard Biochip Technologies). See color insert.

Wright, G.L. Cazares, L.H. Leung, S.M. et al. ProteinChip Surface Enhanced Laser Desorption/ionization (SELDI) Mass Spectrometry A Novel Protein Biochip Technology for Detection of Prostate Cancer Biomarkers in Complex Protein Mixtures, Prostate Cancer and Prostatic Dis., 2, 264-276 (2000). 

In this study, we have demonstrated a new electrochemical method for highly sensitive, accurate, and rapid multiplex detection of colon cancer cells response to differentiation therapy. The development of an electronic biochip array system, adjusted to biological experiments can help tailor cancer treatment to individual patients. Human colon cancer cells, HT-29, were treated with the differentiation therapy drag agents BA, AN-7, and AN-9, and the cells response was simultaneously measured on hue and compared. This microarray technology provides the ability to test on line the affect of multi-drag agents, and to tailor effective therapy to the individual. 

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