Office of Technology Transfer – University of Michigan

Biodegradable Hydrogel using Ultrasound for Tissue Expansion

Technology #6749

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Mario L. Fabiilli
Managed By
Janani Ramaswamy
Licensing Specialist, Medical Deviceses 734-763-9081
Patent Protection
US Patent Pending

Tissue Expansion A material or device designed to induce skin or tissue expansion for the purpose of reconstructive and plastic surgeries has been deemed as a tissue expander. Tissue expanders are temporary inflatable implants that are positioned under the skin to facilitate the increase of tissue dimensions for reconstruction. For instance, inflatable balloons were used for skin expansion. However, the expansion of the silicone balloon takes too long (8–14 weeks), induces tissue necrosis and has to be removed after skin growth resulting in further complications.

Biodegradable Hydrogel for Tissue Expansion

The invention under consideration utilizes a biodegradable hydrogel scaffold that is injected at the site of that can be injected at the desired site of skin growth. The scaffold polymerizes in situ and is ultimately biodegradable. The scaffold also contains a perfluorocarbon (PFC) emulsion that vaporizes from liquid droplets into gas bubbles when implanted. Vaporization of the emulsion can also be facilitated by the application of ultrasound. The resulting gas bubbles, which remain stuck in the matrix, begin to in-gas. Thus, the matrix expands in size and causes the skin the stretch


  • Breast reconstruction after mastectomy
  • restorative dentistry
  • Plastic surgery for scar reconstruction following trauma, burns
  • Repair of cleft palate


  • Biodegradable scaffold reduces infection at the site of expansion
  • Uses ultrasound to control gel expansion