Repairing Damaged Vocal Cords

Aditi Kaveti ’23

Figure 1: Hydrogel scaffold with pores necessary for cell proliferation and survival.

Human vocal cords are structures in the larynx, just above the trachea, that vibrate to create a buzzing tone that becomes what we know as the human voice. This vibration works through resonance, which is the shaping and amplification of sound waves. In patients with laryngeal cancer, vocal cords are at risk due to the mass forming on the glottis. Signs of this growth include prolonged hoarseness or change in the voice. A possible treatment for this type of cancer is a total laryngectomy. This procedure removes the patient’s larynx, inhibiting the patient’s speech through their voice box.

Healing from this type of cancer is a difficult process because of the inevitable damage that is caused to the patient’s vocal cords. The tissues of the vocal cords must be strong enough to withstand the constant movement that occurs while speaking. Dr. Luc Mongeau, the chair of the Department of Mechanical Engineering at McGill University, worked with his team to develop a new injectable hydrogel that can be used for wound repair. A hydrogel is a specific kind of biomaterial that is injected into the body and forms a stable porous structure, which is supported by cross-linking of individual polymer chains. This structure promotes healing by providing room for cells to live and grow in order to repair damaged organs. 

Existing hydrogels had an inverse correlation between porosity and toughness, which Mongeau’s team sought to change in order to create a hydrogel with both high porosity and toughness. In order to achieve this, they orchestrated stepwise gelation and phase separation processes. The hydrogels contain porous double networks (PDNs), that are resilient to millions of cycles of mechanical loading. In addition, this material can form interconnected cell-sized pores in situ upon injection. The team tested this material by performing 6,000,000 cycles of high-frequency biomechanical simulations on the PDNs, which it withstood without rupture. The hydrogel also supported cell survival and rapid medium perfusion due to its highly porous matrices. Future direction for the team includes new opportunities for regenerative medicine involving vocal cords, heart, and muscles, and the exciting ability for this type of hydrogel to serve as a biomimetic in vitro 3D cell culture platforms.

References:

  1. Taheri, S., et al. Injectable, pore-forming, perfusable double-network hydrogels resilient to extreme biomechanical stimulations. Advanced Science (Weinheim, Baden-Wurttemberg, Germany), e2102627. Advance online publication. (2021) https://doi.org/10.1002/advs.202102627
  2. Image retrieved from: https://www.nisenet.org/catalog/scientific-image-hydrogel-scaffold

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