Amyloid β-Binding Bifunctional Chelators with Favorable Lipophilicity for ⁶⁴Cu Positron Emission Tomography Imaging in Alzheimer's Disease

Herein, we report a new series of bifunctional chelators (BFCs) with a high affinity for amyloid aggregates, a strong binding affinity toward Cu(II), and favorable lipophilicity for potential blood-brain barrier penetration. The alkyl carboxylate ester pendant arms offer up to 3 orders of magnitude higher binding affinity toward Cu(II) and enable the BFCs to form stable 64Cu-radiolabeled complexes. Among the five compounds tested, the 64Cu-YW-7 and 64Cu-YW-10 complexes exhibit strong and specific staining of amyloid plaques in ex vivo autoradiography studies. Importantly, these BFCs have promising partition coefficient (log Doct) values of 0.91-1.26 and show some brain uptake in biodistribution studies using CD-1 mice. Overall, these BFCs could serve as lead compounds for the development of positron emission tomography imaging agents for AD diagnosis.