Cardiovascular disease is still the leading cause of mortality in the United States, with 1 million lives lost each year. Cardiovascular patients could benefit by using tissue-engineered living blood vessels as a better source of grafts. Scaffolds play a pivotal role in this tissue engineering but the structural design must consider biocompatibility and biodegradability of the polymers, structured and dense porosity for similarity to the extracellular matrix (ECM), and adequate mechanical properties to support tissue regeneration. However, scaffolds developed up to this point have various drawbacks and limitations: randomly oriented and/or small micropores, non-fibrous walls, and very low degree of lateral interconnectivity.
Researchers at the University of Michigan have developed novel scaffolds fabricated from biodegradable poly(l-lactic acid) (PLLA) by means of thermally induced phase-separation (TIPS) techniques. These microtubular structures can be created in the axial or radial direction with varying porosity and tubular size with adjustments to the polymer concentration, TIPS temperature, and thermal conductivity. Additionally, a one-step TIPS method without the use of template materials can be use to generate nanofibrous scaffolds with an oriented and interconnected microtubular pore network. Again, the scaffold structure can be tailored by adjusting the solvent ratio, phase-separation temperature, and polymer concentration.
Applications and Advantages
- Tissue engineering
- Cell seeding and mass transfer for cell growth and function
- Potential applications to widely varied oriented tissue regeneration: blood vessel, nerve, trachea, intestine, tendon, ligament, bone
- Scaffold structural features can be conveniently adjusted
- Does not require expensive facilities, with straightforward and short preparation time