A Diketopinic Reagent for the Reversible Bioconjugation to Arginine Residues on Native Antibodies.

Arginine is one of the less commonly targeted amino acids in protein bioconjugation, despite its unique reactivity and abundance on the surface of proteins. In this work, a molecule containing diketopinic acid and an azide handle was developed for the chemo-selective bioconjugation to arginine. This compound proved to be efficient for bioconjugation to IgG1 and IgG4 antibodies, achieving mono- and double-label conversion rates of 37-44 and 12-30%, respectively.

Plug-and-play nucleic acid-mediated multimerization of biparatopic nanobodies for molecular imaging.

In cancer molecular imaging, selecting binders with high specificity and affinity for biomarkers is paramount for achieving high-contrast imaging within clinical time frames. Nanobodies have emerged as potent candidates, surpassing antibodies in pre-clinical imaging due to their convenient production, rapid renal clearance, and deeper tissue penetration. Multimerization of nanobodies is a popular strategy to enhance their affinity and pharmacokinetics; however, traditional methods are laborious and may yield heterogeneous products.