Microfabricated devices for genetic diagnostics

This paper presents a review of microfabricated devices for genetic diagnostics. Genetic diagnostics are powerful technology drivers and excellent candidate applications for miniaturization technologies because the demand for inexpensive genetic information is essentially unlimited, and the cost and time for the diagnostic decreases with sample volume. Genetic information is stored in long DNA molecules in solution. This information is processed and extracted using a series of enzymatic and other chemical reactions well known in molecular biology. Processing of DNA molecules in the microscale hence requires the implementation of microfluidic devices capable of handling, mixing, thermal cycling, separating, and detecting nano- and picoliter liquid samples. This paper discusses some of the fundamental macroscale protocols used for genetic analyses and how these processes scale down to microscopic volumes. The construction and performance of microfluidic devices for DNA amplification, separation, hybridization, and detection are discussed, showing that so far, no fundamental impediments exist for genetic diagnostics based on microelectromechanical systems. Some of the unresolved storage and packaging issues and future challenges for the practical implementation of these devices are also presented.