Geometry and length control of 3D engineered heart tissues using direct laser writing

Area of Science:

• Biomaterials Engineering
• Tissue Engineering
• Cardiovascular Research

Background:

• The mechanical and geometric environment significantly impacts Engineered Heart Tissues (EHTs) structure and function.
• Precise control over EHT microenvironment is crucial for successful tissue maturation and functional assessment.

Purpose of the Study:

• To investigate the effects of environmental geometry and mechanical properties on EHT maturation and stability.
• To develop and utilize a high-accuracy 3D tissue culture platform for controlled EHT development.
• To evaluate the functional dynamics of EHTs under electrical pacing.

Main Methods:

• Fabrication of a 3D tissue culture platform using two-photon direct laser writing for precise geometric control.
• Exploration of two distinct seeding well geometries (rectangular and stadium-like) and systematic variation of their lengths.
• Optimization of seeding well stiffness, attachment site configuration, and seeding parameters for enhanced tissue stability.
• Assessment of EHT structure, fiber alignment, and functional dynamics via electrical pacing and calcium imaging.

Main Results:

• Different geometries induce distinct fiber alignment patterns (uniaxial vs. diagonal) in EHTs.
• Increased tissue length correlated positively with fiber alignment but also led to thinning, necking, and eventual failure.
• Optimized platform stiffness and seeding parameters improved tissue stability across different lengths and geometries.
• The platform enabled functional evaluation of EHTs during electrical pacing, correlating frequency with functional dynamics.

Conclusions:

• Environmental geometry and mechanical properties are critical modulators of Engineered Heart Tissue development.
• The developed 3D platform offers precise control for studying EHT maturation and optimizing tissue design.
• This technology facilitates the creation of more stable and functionally relevant EHTs for research and potential therapeutic applications.