Nanodiscs are synthetic phospholipid particles with a distinct morphology and size that enhance their efficiency in drug delivery applications.1 First developed by Sligar et al. in the early 2000s, these model membrane systems measure around 10 nm in diameter with a thickness between 4.6 and 5.6 nm.2 Structurally, nanodiscs are similar to high-density lipoproteins.
In medical applications, nanotechnology advancements have positioned nanodiscs as valuable tools for diagnosing and treating various diseases. These disc-shaped particles can preserve membrane proteins in their functional state outside the cellular environment, making them valuable in biomedical applications.1
Nanodiscs stabilize fragile proteins, enhance drug delivery, and provide a structured bilayer surface, proving highly effective for studying cellular signaling complexes on membrane surfaces.1 Their versatility continues to support advancements in modern medicine.
Classification of Nanodiscs
Nanodiscs can be categorized based on the stabilizer used to maintain their structure.3
Membrane Scaffold Protein Nanodiscs
Membrane scaffold protein (MSP) nanodiscs use amphipathic membrane scaffold proteins as stabilizers. These scaffold proteins encircle a stable, discoidal phospholipid bilayer containing embedded transmembrane proteins, forming the nanodisc structure.
MSP is typically a truncated form of apolipoprotein A-I (apoA-I), a component of high-density lipoproteins. It wraps around a small segment of the phospholipid bilayer to create the disc-shaped nanodisc.3
MSP provides a hydrophobic surface for lipid tails and a hydrophilic outer surface, making nanodiscs highly soluble in water. During assembly, excess detergent is used and later removed with bio-beads, allowing membrane proteins to stay in solution without detergents.
These nanodiscs are well-suited for studying membrane proteins in both prokaryotic and eukaryotic systems, including key structures like transporters, ion channels, and G protein-coupled receptors (GPCRs).4
Saposin nanodiscs
The saposin protein family consists of four members, saposin A–D, each with a molecular weight of around 10 kDa. Saposin A is most commonly used for assembling saposin nanodiscs. Frauenfeld et al. (2016) demonstrated the use of saposin proteins as scaffolds to reconstitute various membrane proteins within a phospholipid environment.5
Saposin nanodiscs self-assemble from saposin proteins, phospholipids, and membrane proteins into a stable structure that is adaptable to various membrane protein sizes without requiring scaffold construction or lipid ratio adjustments.3 Although a recent development, they are widely applied in structure-based techniques like NMR and cryo-EM, providing distinct advantages for both methods.
For example, in a solution-based NMR study, three membrane proteins were successfully incorporated into saposin nanodiscs: bacterial outer membrane protein X (OmpX), sensory receptor rhodopsin II (pSRII), and the β1-adrenergic receptor (β1AR).6
Copolymer Nanodiscs
Copolymer nanodiscs extract membrane proteins directly from cell membranes, preserving their native state and endogenous phospholipids. Synthetic polymers encapsulate the proteins into nanosized discs, stabilizing a portion of the native membrane. These nanodiscs use the cell’s natural phospholipids, with the polymer acting as both solubilizer and stabilizer, removing the need for additional detergents.3
Synthetic copolymers like styrene-maleic acid (SMA), diisobutylene maleic acid (DIBMA), and polymethacrylate (PMA) are used to stabilize nanodiscs, maintaining the lipid bilayer in aqueous solutions. These non-protein polymers self-assemble into stable structures and offer higher purity than MSP nanodiscs. They are widely used in membrane protein research, drug delivery, and biosensor applications.3
SMA nanodiscs have been successfully employed to purify and study integral membrane proteins from bacterial and eukaryotic systems. Once reconstituted into SMA nanodiscs, these proteins are well-suited for high-resolution structural analysis via cryo-EM, as well as for receptor-ligand binding assays and functional activity studies.7
Applications of Nanodiscs in Medicine
Drug Delivery
Nanodiscs offer an effective platform for enhancing drug delivery systems, particularly for drugs with low water solubility. Their lipid bilayer structure can encapsulate hydrophobic drugs, protecting them from premature degradation while enhancing their bioavailability.3
Chen et al. designed lipid nanodiscs functionalized with cyclic RGD peptide (cRGD) on either the edges or planes, creating two distinct anisotropic targeting nanocarriers (E-cRGD-NDs and P-cRGD-NDs) for siRNA delivery.8 E-cRGD-NDs demonstrated significant advantages in siRNA loading, cellular uptake, gene silencing efficiency, protein expression, and in vivo performance.
In a 2023 study, Yu et al. developed antibodies targeting matrix protein 2 (M2) of the influenza A virus. M2 (1-46) was incorporated into nanodiscs to form a membrane-embedded tetrameric structure, closely resembling its natural physiological state within the influenza virus envelope.9
Companies like Cube Biotech are actively developing nanodisc-based drug delivery systems that can be customized for different therapeutic needs. Its lipid-based nanodiscs offer a flexible platform for encapsulating and delivering various pharmaceuticals, including biologics and small-molecule drugs.
Vaccine Development
Nanodiscs have emerged as promising platforms for developing personalized tumor immunotherapy and vaccines against infectious diseases. They can be loaded with antigenic peptides or tumor markers, preserving the structure and activity of membrane proteins, which makes them highly immunogenic.1
Aldehyde dehydrogenase (ALDH) has been extensively used as a marker for isolating cancer stem cells (CSCs). These cells are characterized by high proliferation rates and play a role in tumor metastasis and recurrence.10 ALDH-positive CSCs have been identified in over 20 different tumor types.1
In a 2020 study, James J. Moon’s research group developed synthetic nanodiscs for vaccines targeting ALDHhigh CSCs. These nanodiscs improve antigen delivery to lymph nodes and trigger strong ALDH-specific T-cell responses, offering a promising new approach for cancer immunotherapy focused on CSCs.11
Diagnostic Tools
Nanodiscs offer considerable potential for creating advanced diagnostic tools. Their ability to stabilize membrane proteins in their native conformation makes them excellent tools for studying protein-protein interactions, enzymatic functions, and other cellular processes.12
NMR has long been used to gather structural information on soluble proteins. Rienstra and colleagues were the first to report solid-state NMR (ssNMR) spectra of nanodiscs, confirming that membrane scaffold proteins are organized in a “belt” configuration.13
Recently, there has been substantial growth in the use of both solution and ssNMR methods with nanodiscs, providing critical insights into the structure and function of membrane proteins. For instance, the complete three-dimensional structure of OmpX in nanodiscs, obtained through solution NMR, highlighted the ability to detect subtle conformational differences in a native bilayer environment.14
Conclusion
Nanodiscs represent a transformative innovation in medicine, with applications spanning protein stabilization, drug delivery, vaccine development, and diagnostics. Their ability to mimic natural cell membranes while remaining stable in various environments allows for broad applications in both research and clinical contexts.
Looking ahead, the future of nanodiscs in healthcare is strong. Continued research into polymer-based and MSP nanodiscs could lead to more robust and customizable platforms for therapeutic and diagnostic use.
As more companies and research institutions explore these applications, nanodiscs are likely to support more precise, effective, and personalized treatments in modern medicine.
References and Further Reading
1. Mu, Q., Deng, H., An, X., Liu, G. Liu, C. (2024). Designing nanodiscs as versatile platforms for on-demand therapy. Nanoscale. https://pubs.rsc.org/en/content/articlelanding/2024/nr/d3nr05457h
2. Nath, A., Atkins, WM. Sligar, SG. (2007). Applications of Phospholipid Bilayer Nanodiscs in the Study of Membranes and Membrane Proteins. Biochemistry. https://pubmed.ncbi.nlm.nih.gov/17263563/
3. Dong, Y., Tang, H., Dai, H., Zhao, H. Wang, J. (2024). The application of nanodiscs in membrane protein drug discovery & development and drug delivery. Front. Chem. https://pmc.ncbi.nlm.nih.gov/articles/PMC11445163/
4. Zhang, M. et al. (2021). Cryo-EM structure of an activated GPCR–G protein complex in lipid nanodiscs. Nat. Struct. Mol. Biol. https://pubmed.ncbi.nlm.nih.gov/33633398/
5. Frauenfeld, J. et al. (2016). A saposin-lipoprotein nanoparticle system for membrane proteins. Nat. Methods. https://pubmed.ncbi.nlm.nih.gov/26950744/
6. Chien, C.-T. H. et al. (2017). An adaptable phospholipid membrane mimetic system for solution NMR studies of membrane proteins. J. Am. Chem. Soc. https://pubmed.ncbi.nlm.nih.gov/28990386/
7. Swainsbury, DJK. et al. (2023). Cryo-EM structure of the four-subunit Rhodobacter sphaeroides cytochrome bc 1 complex in styrene maleic acid nanodiscs. Proc. Natl. Acad. Sci. https://www.pnas.org/doi/10.1073/pnas.2217922120
8. Chen, X., Zhou, Y., Zhao, Y. Tang, W. (2023). Targeted degradation of extracellular secreted and membrane proteins. Trends Pharmacol. Sci. https://pubmed.ncbi.nlm.nih.gov/37758536/
9. Yu, C. et al. (2023). Screening and characterization of inhibitory vNAR targeting nanodisc-assembled influenza M2 proteins. Iscience. https://pubmed.ncbi.nlm.nih.gov/36570769/
10. Marcato, P., Dean, CA., Giacomantonio, CA. Lee, PWK. (2011). Aldehyde dehydrogenase: its role as a cancer stem cell marker comes down to the specific isoform. Cell cycle. https://pubmed.ncbi.nlm.nih.gov/21552008/
11. Hassani Najafabadi, A. et al. (2020). Cancer immunotherapy via targeting cancer stem cells using vaccine nanodiscs. Nano Lett. https://pmc.ncbi.nlm.nih.gov/articles/PMC7572838/
12. Denisov, IG. Sligar, SG. (2017). Nanodiscs in membrane biochemistry and biophysics. Chem. Rev. https://pubmed.ncbi.nlm.nih.gov/28177242/
13. Li, Y., Kijac, AZ., Sligar, SG., Rienstra, CM. (2006). Structural analysis of nanoscale self-assembled discoidal lipid bilayers by solid-state NMR spectroscopy. Biophys. J. https://pubmed.ncbi.nlm.nih.gov/16905610/
14. Hagn, F., Wagner, G. (2015). Structure refinement and membrane positioning of selectively labeled OmpX in phospholipid nanodiscs. J. Biomol. NMR. https://pubmed.ncbi.nlm.nih.gov/25430058/
News
By working together, cells can extend their senses beyond their direct environment
The story of the princess and the pea evokes an image of a highly sensitive young royal woman so refined, she can sense a pea under a stack of mattresses. When it comes to [...]
Overworked Brain Cells May Hold the Key to Parkinson’s
Scientists at Gladstone Institutes uncovered a surprising reason why dopamine-producing neurons, crucial for smooth body movements, die in Parkinson’s disease. In mice, when these neurons were kept overactive for weeks, they began to falter, [...]
Old tires find new life: Rubber particles strengthen superhydrophobic coatings against corrosion
Development of highly robust superhydrophobic anti-corrosion coating using recycled tire rubber particles. Superhydrophobic materials offer a strategy for developing marine anti-corrosion materials due to their low solid-liquid contact area and low surface energy. However, [...]
This implant could soon allow you to read minds
Mind reading: Long a science fiction fantasy, today an increasingly concrete scientific goal. Researchers at Stanford University have succeeded in decoding internal language in real time thanks to a brain implant and artificial intelligence. [...]
A New Weapon Against Cancer: Cold Plasma Destroys Hidden Tumor Cells
Cold plasma penetrates deep into tumors and attacks cancer cells. Short-lived molecules were identified as key drivers. Scientists at the Leibniz Institute for Plasma Science and Technology (INP), working with colleagues from Greifswald University Hospital and [...]
This Common Sleep Aid May Also Protect Your Brain From Alzheimer’s
Lemborexant and similar sleep medications show potential for treating tau-related disorders, including Alzheimer’s disease. New research from Washington University School of Medicine in St. Louis shows that a commonly used sleep medication can restore normal sleep patterns and [...]
Sugar-Coated Nanoparticles Boost Cancer Drug Efficacy
A team of researchers at the University of Mississippi has discovered that coating cancer treatment carrying nanoparticles in a sugar-like material increases their treatment efficacy. They reported their findings in Advanced Healthcare Materials. Over a tenth of breast [...]
Nanoparticle-Based Vaccine Shows Promise in Fighting Cancer
In a study published in OncoImmunology, researchers from the German Cancer Research Center and Heidelberg University have created a therapeutic vaccine that mobilizes the immune system to target cancer cells. The researchers demonstrated that virus peptides combined [...]
Quantitative imaging method reveals how cells rapidly sort and transport lipids
Lipids are difficult to detect with light microscopy. Using a new chemical labeling strategy, a Dresden-based team led by André Nadler at the Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG) and [...]
Ancient DNA reveals cause of world’s first recorded pandemic
Scientists have confirmed that the Justinian Plague, the world’s first recorded pandemic, was caused by Yersinia pestis, the same bacterium behind the Black Death. Dating back some 1,500 years and long described in historical texts but [...]
“AI Is Not Intelligent at All” – Expert Warns of Worldwide Threat to Human Dignity
Opaque AI systems risk undermining human rights and dignity. Global cooperation is needed to ensure protection. The rise of artificial intelligence (AI) has changed how people interact, but it also poses a global risk to human [...]
Nanomotors: Where Are They Now?
First introduced in 2004, nanomotors have steadily advanced from a scientific curiosity to a practical technology with wide-ranging applications. This article explores the key developments, recent innovations, and major uses of nanomotors today. A [...]
Study Finds 95% of Tested Beers Contain Toxic “Forever Chemicals”
Researchers found PFAS in 95% of tested beers, with the highest levels linked to contaminated local water sources. Per- and polyfluoroalkyl substances (PFAS), better known as forever chemicals, are gaining notoriety for their ability [...]
Long COVID Symptoms Are Closer To A Stroke Or Parkinson’s Disease Than Fatigue
When most people get sick with COVID-19 today, they think of it as a brief illness, similar to a cold. However, for a large number of people, the illness doesn't end there. The World [...]
The world’s first AI Hospital, developed in China is transforming healthcare
Artificial Intelligence and its developments have had a revolutionary impact on society, and healthcare is not an exception. China has made massive strides in AI integrated healthcare, and continues to do so as AI [...]
Scientists Rewire Immune Cells To Supercharge Cancer-Fighting Power
Blocking a single protein boosts T cell metabolism and tumor-fighting strength. The discovery could lead to next-generation cancer immunotherapies. Scientists have identified a strategy to greatly enhance the cancer-fighting abilities of the immune system’s [...]
