Virus-like particles (VLPs) have gained significant attention and recognition as promising tools for therapeutics delivery as well as vaccine development due to their unique properties and advantages due to their structural stability, high payload capacity, and versatile surface modification potential. VLPs offer a versatile platform for delivering genes and drugs, facilitating targeted and efficient therapies with enhanced safety profiles.
Cryo-TEM can assist in visualizing VLP morphology, assessing sample impurity and determining the particle size distribution. Cryo-TEM imaging can also visualize the internal density of VLPs allowing you to quantify gene or drug cargo loading efficiency. Further, Cryo-TEM can provide a 3D map of the VLP structure, through 2D and 3D classifications which average particles of the same morphology and conformation states. The 3D map of VLP samples can reveal high resolution details of any structural modification and confirm proteins bound to VLPs.
Cryo-TEM is an excellent orthogonal technique that complements and improves data obtained using DLS, AUC, or SEC and is important for establishing the historical comparability and therapeutic and clinical equivalence of the product for FDA filings. NIS is pleased to offer GMP nanoparticle characterization services, please reach out to us to learn more.
NIS is experienced in working with many VLPs including:
Characterize Virus-Like Particles with Cryo-TEM Imaging
Characterize Adeno-associated virus (AAV)
Adeno-associated virus (AAV) is a well-established platform for gene delivery. It is crucial to ensure that AAV formulations are free from impurities that can compromise the efficacy, safety, and immunogenicity of the product. One such impurity is the presence of empty capsids or capsids with incomplete DNA payloads.
Cryo-TEM imaging can directly assess the composition of AAV formulations, enabling precise characterization of empty, partially full, and full capsids, as well as visualizing impurities and level of aggregation.
Further, cryo-TEM imaging can be used to obtain 2D class averages and create high resolution 3D reconstructions of AAV particles. This can help identify potential post-translational modifications on AAV capsids, and decipher the structural impact of mutations on capsid structure and help with understanding of the molecular basis of receptor bound AAV or epitope mapping.
Visualize Human papillomavirus (HPV)
Human papillomavirus (HPV) is a key component in vaccines such as Gardasil®1. Cryo-TEM imaging provides excellent visualization to directly determine morphological characteristics of VLP vaccine intermediates such as HPV, including uniformity, shape, particle integrity, size distribution analysis, and level of aggregation and clustering.
By leveraging Cryo-TEM imaging, scientists can gain valuable insights into batch-to-batch variability, scale-up processes, and process development changes. These insights are vital for understanding and optimizing the production of the final drug formulation.
Cryo-TEM can also provide a 3D reconstruction of the particle’s structure, which is achieved by averaging particles of the same morphology and conformation using single particle particle analysis workflow.
1. Qinjian Zhao, Clinton S Potter, Bridget Carragher, Gabriel Lander, Jaime Sworen, Victoria Towne, Dicky Abraham, Paul Duncan, Michael W Washabaugh & Robert D Sitrin (2014) Characterization of virus-like particles in GARDASIL® by cryo transmission electron microscopy, Human Vaccines & Immunotherapeutics, 10:3, 734-739, DOI: 10.4161/hv.27316
Learn About Lentivirus
Cryo-TEM imaging studies offer valuable insights for the assessment of Lentivirus particle morphology. This advanced imaging technique enables researchers to analyze various structural aspects, including size, shape, uniformity, and integrity of the particles. Further, Cryo-TEM allows for the visualization of important characteristics such as maturation states, surface protein morphology, and decoration, while also allowing the detection of impurities present in each sample lot.
For a deeper understanding of the structural features, such as maturation state, capsid and packaged genomes, and details of the surface proteins, cryo-electron tomography can be performed on a formulation containing heterogeneous populations of particles.