Label-free Biosensors for Health Applications

Biosensors are widely used for health applications. Indeed, the current success of biosensors is attributed to the extraordinary demands of disease diagnoses and control, as well as the ability of biosensors to offer a convenient, hygienic, rapid, and compact method for personal monitoring. Biosensors offer enormous potential for detecting a wide range of analytes in the health care and food industries and in environmental monitoring. As quoted, MicroChips president John Santini expects the technology to be used as in-the-flesh physicians within 10 years: "It's a very exciting time," he says. "Our next step is a manually, wirelessly controlled biosensor that detects and treats an acute condition, and then a biosensor that will approximate an artificial organ; it'll sense a condition and respond automatically without user intervention." In this chapter, we review applications and advances in biosensor technology, focusing on four applications in the health field: 1) investigation of the interaction of antigens with antibodies produced in healthy and diseased subjects, 2) disease markers and virus detection, 3) clinical diagnosis and control of emerging infectious diseases, and 4) market potentials. Specifically, we discuss the application of a label-free biosensor based on ellipsometry in the development of future biosensors, the current and future clinical applications of this technology, and its viability. The goal of this chapter is to provide a brief description of the role of biosensors in in vitro diagnostics and scientific research related to the health field. Readers interested in competing or related technologies (e.g., ellipsometry, microfluidics, and surface modification technologies) are referred to one of several excellent recent reviews (Jin et al., 2011; Qi et al., 2009a; Zhang, et al., 2005). In the following section, health applications are described using a label-free biosensor based on ellipsometry.