Silk protein – also known as fibroin – possesses highly advantageous properties for tissue support and regeneration. As a natural structural protein, silk can provide strength and facilitate tissue ingrowth as it slowly resorbs in the body. The idea is to use the process of tissue ingrowth and support to target areas of tissue weakness, directing new deposition of collagen and providing “lift” to soft tissues. David Kaplan and Fiorenzo Omenetto, professors in the department of biomedical engineering at Tufts University, have, over the past 10 years, generated a volume of scientific literature and intellectual property focused on the myriad applications of silk, including medical applications.

With a patent license from Tufts, Anh Hoang and Howard Weisman founded Sofregen Medical in 2015 to develop a range of new products – from advanced versions of proven biological scaffolds to next-generation aesthetic and medical injectables. Sofregen’s products are intended for use by clinicians in applications requiring soft tissue support and augmentation.

Hoang and Weisman have expanded Sofregen to a team of more than 10 employees that include biomedical engineers and professionals working in finance, medical affairs, sales, and business development.

The first product Sofregen plans to bring to market is a soft tissue filler based on silk protein for the treatment of vocal cord paralysis. Based on technology that transforms silk protein fibers into porous silk protein particles and blends them with an aqueous carrier, the product is intended for delivery through a small syringe needle and is described in an article in the March 2018 issue of Journal of Voice, titled “Injectable Silk Protein Microparticle-Based Fillers: A novel material for potential use in glottic insufficiency.” The authors describe how these highly porous and flexible silk particles have been designed to closely match the biomechanical properties of soft tissue in the human body, making the bulking of the vocal cord an ideal first indication.

Vocal cord dysfunction, including vocal cord insufficiency, currently affects over 8 million adults annually in the United States. Damage to one or both of the vocal folds can result from trauma to the voice box, such as repeated intubation for medical purposes, but it may also be caused by disease or the normal aging process. Many patients will try noninvasive voice therapy to relieve their symptoms. Some will require surgical intervention, and others will pursue treatment with an injection-based material to augment the vocal cord and restore their voices. The water-based injectable gels that are currently available are short acting. Injections based on calcium hydroxyapatite preparations are longer acting but pose delivery challenges: they require skilled assistance to the physician during the procedure for accurate delivery of the product to the vocal cord, and may lead to migration or scarring around the implanted material.

To aid in the delivery of this new vocal cord product, Sofregen has also developed a catheter-based system for easy delivery to the human vocal cord. Dr. Hoang expects that Sofregen’s new implant will overcome current obstacles by introducing a straightforward system – compatible with commercial channel laryngoscopes – to deliver regenerative silk protein and stimulate natural collagen deposition in the vocal cord.

The Sofregen executive team is well-positioned to bring a solution to the problem of vocal cord insufficiency. In addition to her postdoctoral training, Dr. Hoang holds a Ph.D. in material science from Vanderbilt University, where she worked as a National Science Foundation (IGERT) graduate fellow, postdoctoral training in biomedical engineering at Harvard Medical School and Massachusetts General Hospital. Mr. Weisman, an accomplished life sciences entrepreneur with 30 years of experience in pharmaceuticals and medical devices, previously led Seventh Sense Biosystems and has successfully taken early stage companies through regulatory clearances.

“Silk protein has tremendous potential in soft tissue regeneration applications. The vocal cord is similar in many ways to other soft tissue in the human body – comprising collagen, fat, and other connective tissue. We’re excited to have the opportunity to bring a new product to market which will really address a patient’s soft tissue loss, and provide bulking and stability and restoration,” says Hoang.