Stephen Levy

February 3, 2014

2 Min Read
Scaffold Improves Heart Cell Growth

When one's heart is damaged by a heart attack or other injury, it can't heal itself very well. This has prompted researchers at Columbia University (New York, NY) and the University of Minho, Portugal, to look for ways to repair the damage. In "Electrically Conductive Chitosan/Carbon Scaffolds for Cardiac Tissue Engineering," a paper published on Biomacromolecules, the research team reports the results of experiments in growing neonatal rat heart cells on a matrix of chitosan and carbon nanofibers.

Flow chart for the preparation of the scaffolds for the experiment. (Courtesy Martins et al.)

Flow chart for the preparation of the scaffolds for the experiment. (Courtesy Martins et al.)

Building on previous research, the scientists were aware that chitosan, which is derived from the shells of shrimp and other crustaceans, had good enough biocompatibility to serve as a scaffold for growing heart cells, but that chitosan was a poor electrical conductor. Since electrical impulses are what cause a heart to beat, they had to find a solution.

Led by Gordana Vunjak-Novakovic, PhD, professor of biomedical engineering and director of the Laboratory for Stem Cells and Tissue Engineering at Columbia, and Ana M. Martins, PhD, Biomaterials, Biodegradables and Biomimetics Research Group, University of Minho, the researchers reasoned that carbon nanofibers could be used as a doping agent in a chitosan matrix. Carbon nanofibers are good conductors and are biocompatible. To this end, they prepared two types of scaffolds for their experiments.

These scaffolds were made of chitosan only, and a chitosan/carbon nanofiber composite. In the composite, carbon nanofibers were homogeneously dispersed throughout the chitosan matrix. The researchers say that the composite scaffold was highly porous with fully interconnected pores and had excellent electrical properties.

Both scaffolds were seeded with neonatal rat heart cells and cultured for up to 14 days. After 14 days of culturing, the team reports, the pores throughout the scaffold volume were filled with cells. They also saw that the metabolic activity of cells in the chitosan/carbon scaffolds was significantly higher as compared to the cells in the chitosan-only scaffolds. The incorporation of carbon nanofibers also led to increased expression of cardiac-specific genes involved in muscle contraction and electrical coupling.

The researchers say that this study demonstrates that the incorporation of carbon nanofibers into porous chitosan scaffolds improved the properties of their cardiac tissue constructs. They presume this improvement was the result of enhanced transmission of electrical signals between the cells.

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