Virus-like particles

Virus-like particles (VLPs) mimic the structure of viruses and are designed to replicate their organization and morphology. Some VLPs feature glycoproteins decorating their surface, resembling surface spikes in Transmission Electron Microscopy (TEM) images. The expression of this feature signifies the transfection efficiency of the product and impacts its bioactivity.  

Another crucial aspect to consider is the size of the particle, which plays a pivotal role in ensuring product safety and efficacy. In this regard, TEM proves invaluable as a high-resolution imaging technique as size can be determined without influence of protein affinity to particles, particle breakage, and aggregation. Additionally, purity, integrity, and aggregation can each be analyzed simultaneously using one TEM assay.