Summary
This protocol provides starting conditions for differentiating C2C12 myoblasts into contractile myotubes within LunaX ECM. The tuneable 3D matrix supports skeletal muscle modelling across physiologically relevant stiffness conditions while helping minimise construct shrinkage during culture.
What you’ll do
- Prepare LunaX MultiMatrix Low Stiffness ECM and fresh photoinitiator.
- Encapsulate C2C12 cells at a recommended density of 5 × 10⁶ cells/mL.
- Dispense and photocrosslink 30 µL cell-laden ECM domes.
- Expand cells for 24 hours before switching to differentiation medium.
- Culture for 7–12 days and confirm myotube formation by morphology and marker staining.
Protocol at a glance
- Cell model: C2C12 mouse myoblasts harvested at approximately 70–80% confluence.
- Starting density: 5 × 10⁶ cells/mL; higher densities may improve formation and alignment.
- Format: 30 µL domes in a 24-well plate.
- Crosslinking: 10 mW/cm² for 120–180 seconds to achieve approximately 2.5–4 kPa.
- Differentiation: 24-hour expansion followed by 7–12 days in IGF-1-containing differentiation medium.
Expected outcome
Elongated, multinucleated myotubes should become increasingly visible during 7–12 days of differentiation. Successful constructs express skeletal myosin heavy chain and other sarcomeric markers that can be confirmed by whole-mount immunofluorescence.
Critical parameters
- Use healthy C2C12 cells at 70–80% confluence and completely remove residual dissociation enzymes.
- Prepare photoinitiator fresh on the day of use and keep it protected from light.
- Remove all supernatant before resuspending cells to avoid diluting the ECM.
- Mix gently and use reverse pipetting to minimise bubbles and dome disruption.
- Refresh complete differentiation medium every 2 days; alternative myoblast models require optimisation.
