Cell-engineered virus-mimetic nanovesicles for vaccination against enveloped viruses.

Enveloped viruses pose a significant threat to human health, as evidenced by the recent COVID-19 pandemic. Although current vaccine strategies have proven effective in preventing viral infections, the development of innovative vaccine technologies is crucial to fortify our defences against future pandemics. In this study, we introduce a novel platform called cell-engineered virus-mimetic nanovesicles (VNVs) and demonstrate their potential as a vaccine for targeting enveloped viruses. VNVs are generated by extruding plasma membrane-derived blebs through nanoscale membrane filters. These VNVs closely resemble enveloped viruses and extracellular vesicles (EVs) in size and morphology, being densely packed with plasma membrane contents and devoid of materials from other membranous organelles. Due to these properties, VNVs express viral membrane antigens more extensively and homogeneously than EVs expressing the same antigen. In this study, we produced severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) VNVs expressing the SARS-CoV-2 Spike glycoprotein (S) on their surfaces and assessed their preclinical efficacy as a COVID-19 vaccine in experimental animals. The administration of VNVs successfully stimulated the production of S-specific antibodies both systemically and locally, and immune cells isolated from vaccinated mice displayed cytokine responses to S stimulation.

Effect of Electrode Material on the Crystallization of GeTe Grown by Atomic Layer Deposition for Phase Change Random Access Memory.

The electrical switching behavior of the GeTe phase-changing material grown by atomic layer deposition is characterized for the phase change random access memory (PCRAM) application. Planar-type PCRAM devices are fabricated with a TiN or W bottom electrode (BE). The crystallization behavior is characterized by applying an electrical pulse train and analyzed by applying the Johnson-Mehl-Avrami kinetics model. The device with TiN BE shows a high Avrami coefficient (>4), meaning that continuous and multiple nucleations occur during crystallization (set switching). Meanwhile, the device with W BE shows a smaller Avrami coefficient (~3), representing retarded nucleation during the crystallization. In addition, larger voltage and power are necessary for crystallization in case of the device with W BE. It is believed that the thermal conductivity of the BE material affects the temperature distribution in the device, resulting in different crystallization kinetics and set switching behavior.