Bioassembly of multicellular spheroids to mimic complex tissue structure using surface-modified magnetized nanofibers

Area of Science:

• Biofabrication and Tissue Engineering
• Materials Science in Medicine
• Regenerative Medicine

Background:

• Creating complex organ models without scaffolds is a significant challenge in biofabrication.
• Existing methods struggle to achieve precise control over microtissue structure and function.
• Scaffold-free approaches are needed for more authentic organoid development.

Purpose of the Study:

• To introduce a novel method for scaffold-free microtissue construction using surface-modifiable magnetic nanofibers.
• To demonstrate precise control over spheroid function and geometry for creating multi-domain microtissues.
• To explore the potential of this method in organ modeling and regenerative medicine.

Main Methods:

• Electrospinning of magnetic nanoparticles within poly-L-lactic acid to create magnetic nanofibers.
• Coating nanofibers with polydopamine (PD) to enhance biological functions, including reactive oxygen species (ROS) scavenging.
• Incorporating PD-coated magnetic fibers (PMFs) into human dermal fibroblast spheroids and manipulating assembled structures using magnetic forces.

Main Results:

• PMFs imparted magnetic responsiveness to spheroids, enabling assembly into various 3D structures (linear, triangular, square).
• PMFs upregulated antioxidant gene expression (superoxide dismutase-1, glutathione peroxidase-1), conferring ROS resistance to spheroids.
• Assembled microtissues containing fibroblasts and endothelial cells mimicked vascular structures under magnetic manipulation.

Conclusions:

• Surface-modifiable magnetic nanofibers offer precise control over microtissue formation and function.
• This scaffold-free biofabrication technique facilitates the creation of complex, multi-domain microtissues.
• The method shows significant promise for advancing organ modeling and regenerative medicine applications.