Abstract
Nanobodies, also known as single-domain antibodies or variable domains of heavy-chain-only antibodies (VHHs), are the antigen-binding domains derived from heavy-chain-only antibodies that naturally occur in camelids. Since their discovery in the early 1990s, Nanobodies have attracted significant attention in the fields of biotechnology, structural biology, diagnostics, and therapeutics. Their unique structural and biochemical properties distinguish them from conventional antibodies and offer several practical advantages as versatile modular units in next-generation biologics. We discuss the most important and useful properties of Nanobodies, including their generation, physicochemical characteristics, manufacturability, stability, immunogenicity, antigen recognition capabilities, functional modulation, and engineering flexibility. We review the development and production of multivalent and multispecific Nanobody constructs; strategies to extend their in vivo half-life; and various functional fusions, including immunotoxins, imaging agents, and cellular therapies such as CAR T cell constructs.