Imaging the mechanical properties of a developing embryonic tendon using Brillouin microscopy

Area of Science:

• Biophysics
• Developmental Biology
• Materials Science

Background:

• Tendon mechanical properties are crucial for musculoskeletal function, but their developmental mechanisms are not fully understood.
• Conventional methods like atomic force microscopy and tensile testing are contact-based, potentially damaging delicate embryonic tissues.
• Brillouin confocal microscopy offers a non-contact, label-free optical approach to assess tissue mechanics.

Purpose of the Study:

• To implement Brillouin confocal microscopy for characterizing chick embryo Achilles tendon mechanical properties.
• To validate Brillouin microscopy measurements against established tensile testing data.
• To explore the potential of Brillouin microscopy for in vivo and spatial mapping of tendon mechanical properties during development.

Main Methods:

• Brillouin confocal microscopy was used to measure mechanical properties of chick embryo Achilles tendons.
• Measurements were validated by comparison with existing tensile modulus data.
• The technique was applied to assess developing tendons, experimentally altered crosslinking, and in vivo conditions.

Main Results:

• Brillouin microscopy successfully quantified significant developmental changes in tendon mechanical properties.
• The technique revealed increasing mechanical heterogeneity in developing tendons.
• Spatial mapping of mechanical properties and in vivo measurements within the limb were demonstrated.

Conclusions:

• Brillouin confocal microscopy is a viable, non-contact method for quantitative and spatial analysis of embryonic tendon mechanical properties.
• This technique enables mechanistic discoveries not possible with conventional methods.
• Findings could inform the development of novel therapeutics for tendon injuries and disorders.