Ultrascan 4000 ccd camera model 895

The purified and assembled VLP samples were diluted to a final concentration of 50 μg/mL and blotted on the freshly glow-discharged, carbon-coated 200 mesh copper grids (EMS, USA) for 1 min. The filter paper was used to blot away an excess sample. The sample on the grid was subsequently washed once with ddH₂O followed by blotting. Grids were negatively stained with uranyl acetate solution (5 μL, 2% w/v) for imaging with JEM1400 at 120 keV and recorded by a Gatan Ultrascan 4000 CCD-camera model 895 (4k × 4k) (Gatan Inc., USA) at magnification 60,000×.

Tibialis anterior or gastrocnemius muscles were imaged at the Facility for Electron Microscopy Research at McGill University (Montreal, Quebec, Canada). The tissue samples were fixed overnight in 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer. The tissues were then postfixed with 1% OsO₄ + 1.5% potassium ferrocyanide in 0.1 M sodium cacodylate buffer for 2 h at 4°C and washed three times with Milli‐Q water. The tissues were dehydrated in a graded series of acetone‐dH₂O up to 100%. Following dehydration, the tissues were infiltrated with a graded series of Epon‐acetone (1:1, 2:1, 3:1), embedded in 100% Epon, and polymerized at 65°C for 48 h. Ultrathin serial sections (90–100 nm thick) were prepared from the embedded tissue blocks with a Diatome diamond knife using a Leica Microsystems EM UC6 ultramicrotome, transferred onto 200‐mesh copper TEM grids, and poststained with 4% uranyl acetate for six minutes and Reynold's lead citrate for five minutes. The ultrathin sections were imaged by an FEI Tecnai G2 Spirit 120 kV TEM equipped with a Gatan UltraScan 4000 CCD Camera Model 895. The proprietary Gatan Digital Micrograph 16‐bit images (DM3) were subsequently converted to unsigned 8‐bit TIFF images.