A robust and versatile nanobody platform for drug delivery

Therapeutic and diagnostic efficacies of numerous small biomolecules and chemical compounds are hampered by the short half-lives. Here we report the development of a repertoire of diverse, high-affinity albumin-nanobodies (Nb HSA ) to facilitate drug delivery. By integrating biophysics, and hybrid structural biology, we have systematically characterized the Nb HSA for albumin binding, mapped the epitopes, and resolved the architecture of a tetrameric Nb-albumin complex. We employed quantitative proteomics for accurate, multiplex Nb pharmacokinetic analysis. Using a humanized albumin mouse model, we found that the Nb HSA has outstanding pharmacokinetics; the most stable Nb HSA has a 771-fold T 1/2 improvement compared with a control Nb. Interestingly, the pharmacokinetics of Nb HSA is related to their biophysical and structural properties. To demonstrate the utility of Nb HSA , we developed a highly stable Nb HSA -hIL-2 cytokine conjugate “Duraleukin” and confirmed its improved anticancer properties than hIL-2 alone. We envision that this high-quality Nb resource will advance research into novel biotherapeutics.