Direct quantification of PTD transduction using real-time monitoring

Protein transduction domains (PTD or cell-permeable proteins) have attracted much attention as drug carriers because of their ability to penetrate cellular membranes. Although numerous PTD have been identified and their properties elucidated, their mechanism of action has not been fully understood due to the absence of a reliable quantification method. This chapter provides a direct method for quantifying cellular transduction of PTD in vitro and in vivo using bioluminescence imaging (BLI). This methodology exploits noninvasive techniques to create an environment suitable for the real-time imaging of PTD transduction and is therefore a promising tool for studying the mechanism of PTD transduction and the in vivo application of new therapeutic candidates.