Methods to Quantify Nanomaterial Association with, and Distribution Across, the Blood-Brain Barrier In Vivo

The role and functional anatomy of the blood-brain barrier (BBB) is summarized to enable the investigator to appropriately address evaluation of nanomaterial interaction with, and distribution across, it into brain tissue (parenchyma). Transport mechanisms across the BBB are presented, in relation to nanomaterial physicochemical properties. Measures and test substances to assess BBB integrity/disruption/permeation are introduced, along with how they are used to interpret the results obtained with the presented methods. Experimental pitfalls and misinterpretation of results of studies of brain nanomaterial uptake are briefly summarized, that can be avoided with the methods presented in this chapter. Two methods are presented. The in situ brain perfusion technique is used to determine rate and extent of nanomaterial distribution into the brain. The capillary depletion method separates brain parenchymal tissue from the endothelial cells that contribute to the BBB. It is used to verify nanomaterial brain tissue entry. These methods are best used together, the latter refining the results obtained with the former. Details of the materials and equipment needed to conduct these methods, and description of the procedures and data interpretation, are provided.