Non-invasive pH determination adjacent to degradable biomaterials in vivo

An appropriate pH level is an important prerequisite for the physiologal functioning of cells and tissues. Changes in the extracellular pH often lead to specific cellular reactions and an altered metabolism of cells and tissues influences the extracellular pH range. Thus a method to monitor the extracellular pH is a valuable tool to track specific tissue reactions. In this article we describe a method for the determination of the pH range adjacent to degradable biomaterials using wireless in vivo imaging. Using hairless but immunocompetent mice the fluorophor 5-(6)-carboxy SNARF-1 and the in vivo fluorescence and multispectral acquisition and analysis system Maestro it is possible to track shifts in pH in small living animals over a longer period of time. This method is especially suitable for studies which focus on the interaction of degrading biomaterials with their adjacent tissues.