DNA microarrays are becoming a widespread tool used in life science and drug screening due to its many benefits of
miniaturization and integration. Microarrays permit a highly multiplexed DNA analysis. Recently, the development of
new detection methods and simplified methodologies has rapidly expanded the use of microarray technologies from
predominantly gene expression analysis into the arena of diagnostics. Osmetech's eSensor<sup>®</sup> is an electrochemical
detection platform based on a low-to- medium density DNA hybridization array on a cost-effective printed circuit board
substrate. eSensor<sup>®</sup> has been cleared by FDA for Warfarin sensitivity test and Cystic Fibrosis Carrier Detection. Other
genetic-based diagnostic and infectious disease detection tests are under development. The eSensor<sup>®</sup> platform eliminates
the need for an expensive laser-based optical system and fluorescent reagents. It allows one to perform hybridization and
detection in a single and small instrument without any fluidic processing and handling. Furthermore, the eSensor<sup>®</sup>
platform is readily adaptable to on-chip sample-to-answer genetic analyses using microfluidics technology. The
eSensor<sup>®</sup> platform provides a cost-effective solution to direct sample-to-answer genetic analysis, and thus have a
potential impact in the fields of point-of-care genetic analysis, environmental testing, and biological warfare agent
Biotechnology, in conjunction with semiconductor and microelectronics, would have a tremendous impact on new solutions in gene and drug discovery, point-of-care systems, pharmacogenomics, and environmental and food safety applications. A combination of microfabrication techniques and molecular biology procedures have the potential to produce powerful, inexpensive, and miniature analytical devices (e.g., microfluidic lab chips), aiding further development of genetic analysis. Microfluidics for biotechnology applications require development of inexpensive, high-volume fabrication techniques and reduction of biochemical assays to the chip format. We discuss design, fabrication, and testing of plastic microfluidic devices for on-chip genetic sample preparation and DNA microarray detection. Plastic microfabrication methods are being used to produce components of a complete microsystem for genetic analysis. A detailed discussion on the development of micromixers, microvalves, cell capture, micro-polymerase chain reaction (PCR) devices, and biochannel hybridization arrays is given. We also describe a path to further individual component integration.
Microfluidics is emerging as one of the fastest growing segments of micro-electro-mechanical system (MEMS) technologies due to its potential applications in biotechnology, chemical microreactors, and drug discovery. Micromixing is one of the most challenging problems in microfluidic systems, since it is a diffusion-limited process and can be very inefficient. A micromixing device based on an acoustic microstreaming principle is developed to enhance micromixing. The micromixer uses air bubbles as actuators that can be set into vibration by a sound field. The vibration of the air bubbles generates steady circulatory flows, resulting in global convection flows and thus rapid mixing. The time to fully mix dyed solutions in a 50-μL shallow chamber using acoustic microstreaming is significantly reduced from hours (a pure diffusion-based mixing) to 6 s. We demonstrate the use of this micromixer to enhance the performance of conventional DNA microarray biochips that often suffer from lengthy hybridization and poor signal uniformity due to a diffusion-limited hybridization process. Experiments showed that the acoustic micromixer results in five-fold hybridization signal enhancement with significantly improved signal uniformity, as compared to conventional diffusion-based biochips. Acoustic microstreaming has many advantages over most existing micromixing techniques, including a simple apparatus, ease of implementation, low power consumption (∼ 2 mW), and low cost.