Membrane proteins, which make up approximately 30% of all proteins encoded by the human genome, represent more than 60% of drug targets [1,2]. However, antibody discovery against membrane proteins remains a significant challenge due to the difficulty in maintaining the structure and functionality of these proteins outside their native lipid environment. Additionally, their dynamic conformations, limited availability of accessible immunogenic regions, and the complexities of antibody screening further complicate the identification and targeting of specific epitopes for antibody binding [3].

While detergents are widely used to solubilize membrane proteins by mimicking the hydrophobic lipid bilayer environment, their use often destabilizes these proteins, potentially leading to aggregation or partial unfolding—as seen in cases like G-protein-coupled receptors (GPCRs) and transporters [4]. Additionally, detergents may strip away essential lipid molecules, distorting protein structure. These structural perturbations can sometimes compromise function and reduce antigenicity [5], limiting the effectiveness of detergents in antibody discovery applications. Detergent-based formulations have also been problematic for high-throughput antibody screening platforms such as phage display or hybridoma technologies, as conformational changes can alter epitope availability and affinity.

Nanodiscs, which provide a native-like lipid bilayer environment for embedding membrane proteins, have emerged as a powerful tool in membrane protein research, including antibody discovery. They stabilize membrane proteins by wrapping around their hydrophobic regions, thus keeping membrane proteins soluble in aqueous solutions while retaining their functional and structural properties. These self-assembling structures are typically formed using membrane scaffold proteins (MSPs) derived from apolipoprotein A-I along with synthetic or natural lipids, allowing fine-tuning of lipid–protein interactions in the target protein [6]. The term “nanodiscs” is now broadly used to refer to lipid nanoparticles stabilized by other amphipathic structures, including saposin–lipoprotein nanoparticles (Salipro), a lipid-binding protein-based belt system, peptides, or synthetic polymers [7, 8, 9, 10] (Figure 1). Protein engineering of the amphipathic α-helical repeats in MSP or adjusting the saposin A to lipid ratio allows for tunable nanodisc size with high versatility toward various membrane protein families [11,12]. Synthetic polymers like styrene-maleic acid (SMA) copolymers can directly extract membrane proteins, forming nanodiscs with native lipids known as SMA lipid particles (SMALPs) [13].

Nanodiscs have been used in various antibody discovery platforms. By preserving the structural and functional integrity of membrane proteins, nanodiscs enable the display of native epitopes, which is crucial for antibody generation and binding. Moreover, nanodiscs offer a homogenous presentation of membrane proteins, which is essential for screening and antibody selection. Nanodiscs also provide the stability required for large multisubunit complexes, such as ion channels and multisubunit receptors, allowing antibody discovery against targets previously thought too complex [14]. Additionally, the ability to work with native-like proteins can streamline the drug discovery process, as antibodies identified using these formulations are more likely to retain efficacy in vivo.

In this review we will summarize recent advances in antibody discovery using nanodiscs to display the target membrane protein antigen in a soluble format. We will use the terms antibody and nanobody interchangeably, with nanobodies representing heavy -chain -only antibodies from camelids or display libraries. The focus is on key antibody discovery processes that enable lead antibody selection, including immunization, binder identification, affinity, and costructure analysis (Figure 2). In contrast with cell- and detergent-based methods, we aim to showcase the potential of nanodiscs to expedite therapeutic antibody discovery.