Office of Technology Transfer – University of Michigan

Polymeric RNA Delivery Systems for Controlled Release

Technology #6382

RNA-based therapeutics is a growing field of research which is expected to continue growth in coming years. Though few therapies have been commercialized to date, the uses of RNA extend to treatments addressing disease, genetic disorders, cancers and regenerative medicine among others. It is expected that by 2020 therapies based on RNA technologies will generate $1.2B in revenue. One complication which has limited the effect of RNA therapeutics is difficulty inserting the RNA into human cells. Viral vectors may cause immune response and complications, while the use of liposomes to protect and insert the RNA into cells summer from low transfection rate and instability. Addressing these issues is often expensive and impractical as it requires modification of RNA molecules. The use of polymers as low-cost and versatile RNA molecule vectors has been explored, but toxicity and transfection issues have impeded adoption of this method.

Effective transfection and treatment using microspheres of polymer-RNA polyplexes

The development of a biodegradable, low-toxicity non-viral vector for efficient transfection of RNA molecules that allows for controlled release has many potential applications in regenerative medicine. The polymer-based delivery system combines hyperbranched polymers with RNA molecules to form polyplexes. The polymer-RNA polyplexes are encapsulated into biodegradable microspheres which allow for controlled long term release of RNA molecules into the body. Additionally, the microspheres can be incorporated into a nano-fibrous scaffold that can be implanted at wound sites where the RNA polyplexes activate local cells to regenerate local tissues. The technology has been shown to be effective in calvarial bone regeneration in mouse models.


  • Non-viral vector – no immune response
  • Controlled-release
  • Low toxicity
  • Highly efficient transfection
  • Biodegradable polymer structures
  • Bone regeneration without introduction of external cells


  • Biological and medical therapies
  • Regenerative therapies
  • Tissue engineering