The use of holographic elements as biochemical sensors is suggested and exemplified with a device for monitoring protease activity. A quantitative optical response of a holographic element constructed in gelatin is demonstrated for a range of trypsin concentrations down to 25 nM with a response time within 20 min. These data demonstrate the principle for a general protease sensor which has particular relevance to the measurement of trypsin activity below normal physiological duodenal levels. The holographic devices respond with a change in wavelength (color) and/or a change in brightness. The possibility of creating a family of specific, reagentiess, low-cost holographic sensors with direct visual output is outlined. © 1995, American Chemical Society. All rights reserved.
