Calcium concentration measurement by local fluorescent-dye Injection

A system for making in vivo measurements of calcium-ion concentration is proposed. It uses a glass micro injector to locally inject a calcium indicator (fluorescent dye) in target living tissue. The fluorescent dye bonds with calcium ions to produce a level of fluorescence dependent on the concentration of those ions. The micro injector also acts as a fluorescence pickup using a photo detector installed at its base. This system injects fluorescent dye in a localized area and measures fluorescence all in a short time without having to remove living tissue from the organism in question. As such, it is a very minimally invasive measurement system that provides the essential elements of in vivo measurement. In this paper, we describe the characteristics of the injection part and fluorescence-detection part making up the system. In the injection part, we clarified the characteristics of injecting fluorescent dye by an applied voltage. Calcium concentration was measured by the fluorescence response during the injection. In the fluorescence-detection part, the glass micro injector as the pickup was proved to be suitable for measuring the localized response. Then describe the construction and evaluation of a test device combining these parts, and examine the validity of this measurement system.