Optical Biochips

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, efficiency, and speed with which light can be generated, manipulated, detected, and used to sense the effects of many chemical reactions, optical techniques have become the method of choice for many sensing problems involving bio-active molecules. A particularly 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 bioactive molecules are also known as biochips, although this name is used for many different levels of integration. Applications of these optical biochips include 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 integrating complete optical measurement systems on one single, self-contained biochip of unprecedented complexity and functionality.