Nanobodies, also known as single-domain antibodies or VHH (Variable Heavy Chain of Heavy Chain Antibodies), are a novel class of antibody-derived binding proteins. Originally discovered in camelids (camels, llamas, and alpacas) and cartilaginous fish, nanobodies have gained significant attention in both research and therapeutic applications due to their unique properties and advantages over conventional antibodies.

Characteristics of Nanobodies

1. Small Size and High Affinity

Compact Structure: Nanobodies are approximately 15 kDa in size, which is about one-tenth the size of a full-length antibody. This compact structure allows them to access epitopes that are difficult for conventional antibodies to reach.

High Affinity and Specificity: Despite their small size, nanobodies exhibit high affinity and specificity for their targets, often comparable to or even exceeding that of traditional antibodies.

2. Stability and Solubility

Thermal and Chemical Stability: Nanobodies are highly stable under a wide range of temperatures and pH conditions, making them suitable for various environments and applications.

Solubility: They are generally more soluble than conventional antibodies, which can be an advantage in certain formulations and applications.

3. Ease of Production and Engineering

Recombinant Expression: Nanobodies can be easily produced in various expression systems, including bacteria, yeast, and mammalian cells, using standard recombinant DNA techniques.

Genetic Engineering: The small size and simple structure of nanobodies make them amenable to genetic engineering, allowing for the creation of fusion proteins, multivalent constructs, and other modified forms.

4. Versatility in Applications

Assays: Nanobodies can be used in a variety of assays, such as ELISA, flow cytometry, and immunohistochemistry, due to their high specificity and stability.

Therapeutic Agents: They are being explored as therapeutic agents for a wide range of diseases, including cancer, autoimmune disorders, and infectious diseases. Their small size and ability to penetrate tissues make them particularly promising for targeted therapies.

Research Reagents: Nanobodies are valuable tools in basic research, enabling the study of protein-protein interactions,