Biomedical Engineering Reference
In-Depth Information
12
Optical Biochips
P. Seitz
The citizens of our modern society are exposed to an increasing number of
chemical substances that are potentially harmful or that need to be monitored
and kept under check. At the same time, everybody would like to know much
earlier, with higher certainty and at lower cost, whether her or his health is
affected in any way. For this reason there is a huge demand for very sensitive,
highly specific, cost-effective, and rapid methods to detect the concentration
of bio-active molecules. Because of the simplicity, e
ciency, and speed with
which light can be generated, manipulated, detected, and used to sense the ef-
fects of many chemical reactions, optical techniques have become the method
of choice for many sensing problems involving bio-active molecules. A par-
ticularly attractive aspect is the possibility to miniaturize and to parallelize
optical measurements, which has led to the very active field of integrated
optical sensing [1]. Such miniaturized optical systems for the sensing of bio-
active molecules are also known as biochips, although this name is used for
many different levels of integration. Applications of these optical biochips in-
clude medical diagnostics (for specialized laboratories and increasingly also
for home use), contaminant detection in the food industry (e.g., hormones
in milk or meat), pharmaceutical research and development (drug screening),
environmental and pollution monitoring (e.g., pesticides in water), security
and counter-terrorism (detection of chemical and biological warfare agents),
as well as process and quality control in industry.
The present contribution reviews the different principles and realizations of
optical biochips, and it offers an outlook on the potential of monolithically in-
tegrating complete optical measurement systems on one single, self-contained
biochip of unprecedented complexity and functionality.
12.1 Taxonomy of Optical Biochips
12.1.1 Basic Architecture of Optical Biochips
The principle architecture of an optical measurement system for bio-active
molecules is illustrated in Fig. 12.1. Coordinated by an electronic control
