A major challenge confronting the further advancement of using molecular transporters conjugated to small molecular weight therapeutics in the clinic is the development of linkers that would allow for the controllable release of a free drug/probe only after cell entry. Development of assays that would allow for the rapid real-time quantification of transporter conjugate uptake and cargo release in cells and animals would greatly help in their development. In this chapter, we describe a imaging method that quantitatively measures transporter conjugate uptake and cargo release in real-time in both cell culture and animal models.
