Fractals in tissue engineering: toward biomimetic cell-culture matrices, microsystems and microstructured implants

Abstract

Tissue engineering is a rapidly evolving field in which the complexity of biomaterials and biostructures, with typically non-Euclidean or fractal-like geometries, has to be adequately taken into account for the promotion of enhanced and even personalized diagnostic and therapeutic solutions. This study covers the main applications of fractals in the field of tissue engineering, including their advantages for modeling biological processes and cell-culture procedures, but specially focusing on their benefits for describing the complex geometries and structures of biomaterials (both natural and synthetic), many of which have potential uses for the development of cell culture microsystems, scaffolds for tissue repair and implants for tissue repair in general. We also explore the main supporting design, simulation and manufacturing technologies, as well as the most remarkable difficulties and limitations linked to the generalized use of fractals in engineering design, and also detail some current solution proposals and future directions.

Keywords::

• cell-culture matrices
• computer-aided design
• extracellular matrices
• fractal geometry
• fractals
• microsystems
• rapid-prototyping scaffolds
• tissue engineering

Acknowledgements

AD Lantada acknowledges the inspiring example and continued support of Prof. Dr. Pilar Lafont Morgado, as well as the stimulating conversations with Prof. Dr. Josefa Predestinación García-Ruíz and with Dr. José Luis Endrino. The authors are also grateful to the UPM Product Development Laboratory (www.ldp.etsii.upm.es) and especially to Mr. Pedro Ortego García for his outstanding help with prototyping tasks.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• • Fractal geometry is adequate for the modeling, simulation and design of biomimetic medical devices for tissue engineering and tissue repair, although conventional computer-aided and engineering resources do not incorporate them properly.

• • A complement for conventional computer-aided design (CAD) approach, probably incorporating algorithmic tools, is required for providing designers with additional freedom of creation when designing biodevices with complex structures and surfaces.

• • Improving the features of additive manufacturing technologies, mainly precision, manufacture speed and final attainable part size, will help to incorporate fractal micrometric details to the structures and surfaces of commercial implants.

• • An adequate assessment of the actual impact of fractal dimension on cell dynamics, growth, tissue formation and final tissue repair, for its validation as principal design control parameter is necessary.

• • Additional personalization may be obtained by linking medical imaging technologies, fractal-based image analysis and fractal-based design resources, for providing each tissue under repair with the most adequate scaffold or implant geometry.

Notes