Synthetic Tissue to Repair Heart, Muscle, and Vocal Cords

Scientists at McGill University have developed a biomaterial tough enough to repair the heart, muscles, and vocal cords. This development combines advances in chemistry, physics, biology, and engineering. According to the scientists, it represents a major advance in regenerative medicine.

"Our work highlights the synergy of materials science, mechanical engineering and bioengineering in creating novel biomaterials with unprecedented performance,” says research co-leader Jianyu Li in a press release issued by McGill University. “We are looking forward to translating them into the clinic."

A paper is published in Advanced Science. It describes the new biomaterial, which is an injectable hydrogel for wound repair. The hydrogel is a type of biomaterial that provides room for cells to live and grow. Once injected into the body, the biomaterial forms a stable, porous structure allowing live cells to grow or pass through to repair the injured organs.

"People recovering from heart damage often face a long and tricky journey. Healing is challenging because of the constant movement tissues must withstand as the heart beats. The same is true for vocal cords. Until now there was no injectable material strong enough for the job," says researcher Guangyu Bao.

“The results are promising, and we hope that one day the new hydrogel will be used as an implant to restore the voice of people with damaged vocal cords, for example laryngeal cancer survivors."

Physics World explains that “injectable hydrogels are desirable in many areas of regenerative medicine, from drug delivery to lab-on-a-chip disease models.” But many hydrogels break down under stress due to their porous structure. Porosity allows oxygen and nutrients to perfuse through implantable biomaterials. But it often comes at the expense of mechanical strength.

Biological tissues such as the heart and the vocal cords are constantly vibrating. And designing synthetic tissue that can survive vibrations remains a challenge in regenerative medicine. The McGill researchers developed a porous “double-network” hydrogel that is able to withstand millions of cycles of mechanical loading better than the “single-network” hydrogels that have been used so far.

“Most synthetic materials developed so far for vocal cord repair are based on single-network hydrogels,” Bao told Physics World. “Currently, patients may need periodic injections because those hydrogels do not last long. Our hydrogel offers a 5- to 40-fold increase in toughness, which could potentially improve the retention of the hydrogel after injection.”

According to the scientists, this innovation could enable applications like drug delivery, tissue engineering, and the creation of model tissues for drug screening. The scientists are looking to use the hydrogel technology to create lungs to test COVID-19 drugs.