Silicon Based BioMEMS: Micromachining Technologies

This chapter discusses silicon based bioMEMS-micromachining technologies. BioMEMS, or Bio-Micro-Electro-Mechanical Systems, integrates microsystems technology with applications in biology and the life sciences. Disposable and miniature clinical diagnostic systems are mechanisms to increase patient throughput in point-of-care clinical settings. In addition to being painful and causing patient discomfort, syringe injection can potentially release high concentrations of the drug to the entire body. This can cause unintended systemic effects that are correlated with drug side effects. A new class of transdermal devices is a microstructured array of hollow microneedles. When applied to the skin, these microneedles pierce the topmost layer of the skin, opening micropores. The current brain-computer interface (BCI) approaches, including those using surface electroencephalogram, lack functional stability due to cell and tissue reactive responses that occur around implanted devices. The body's response results in the formation of a dense cellular sheath around the implanted electrode arrays, which increases the device impedance and leads to a loss of device functionality. Many types of biosensors have been proposed for detection of biological molecules. The ability to detect small amounts of materials, including biological entities such as pathogenic bacteria, is important for medical diagnostics, detection of infectious agents, mass based flow cytometry, and sizing of colloidal particles. Engineered micro- and nano-mechanical systems serve as multifunctional, highly sensitive, immunospecific biological detectors. Overall, there are four key issues that dominate the development of silicon BioMEMS devices-delivery, performance, complexity of fabrication, and costs.