Nanotechnology, Scaffolds, Tissue Engineering and Organ Transplantation

On July 7, 2011, University College London made an announcement of an breakthrough which is an historic landmark in the field of nanotechnology in tissue engineering: surgeons in Sweden have successfully implanted, for the first time ever, a totally synthetic, tissue-engineered organ (a trachea) into a patient suffering from a terminal-stage tracheal cancer.

A team leaded by Professor Alexander Seifalian (UCL Division of Surgery & Interventional Science; professor of nanotechnology and regenerative medicine at University College London, UK), whose laboratories are headquartered at the Royal Free Hospital, created a glass mold of the patient’s trachea from X-ray computed tomography (CT) scans of the patient. In CT, digital geometry processing is employed to generate a 3D image of the inside of an object from a large series of 2D X-ray images taken around one single axis of rotation.

Then, they manufactured a full size y-shaped trachea scaffold at Professor Seifalian’s laboratories. The scaffold of the trachea was built using a novel nanocomposite polymer developed and patented by Professor Seifalian. Professor Seifalian worked together with Professor Paolo Macchiarini at Karolinska Institutet, Stockholm, Sweden (who also holds an Honorary appointment at UCL).

Professor Seifalian and his team used a porous novel nanocomposite polymer to build the y-shaped trachea scaffold. The pores were millions of little holes, providing this way a place for the patient’s stem cells to grow roots. The team cut strips of the novel nanocomposite polymer and wrapped them around the glass mold creating this way the cartilage rings that conferred structural strength to the trachea.

After the scaffold construct was finished, it was taken to Karolinska Institutet where the patient’s stem cells were seeded by Professor Macchiarini’s team.

For this purpose, a solution of stem cells from the patient’s bone marrow was poured onto the synthetic trachea. The solution included chemicals that induced the cells to differentiate into the types of cells found in a trachea. Tissue was grown on top of the scaffold from the patient’s own stem cells inside a bioreactor (the InBreath, specially designed for the procedure by Harvard Bioscience) to:

• Protect the organ;
• Provide the correct environment for cells differentiation and tissue growth (e.g. sterile and warm);
• Promote cell differentiation and growth.

It took about two days for tissues to form the world first totally synthetic, tissue-engineered trachea.

Finally, the implant surgery was carried out (June 2011) by Professor Macchiarini (at KarolinskaUniversityHospital in Huddinge, Stockholm, Sweden). The patient has now made a full recovery.

This work is highly relevant due to the following reasons:

• It is a pioneer work:
  • In the field of nanomaterials. The nanomaterials have other potential uses such as coronary stents and grafts;
  • In the field of nanotechnology applied to the construction of scaffolds for tissue engineering. Scaffolds play a key role in regenerative medicine and tissue engineering. Doors will be opened to the improvement of these constructs;
  • In the field of nanotechnology applied to tissue engineering. Doors will be opened to mere breakthroughs in the field of regenerative medicine and regenerative medicine;
  • In the field of nanotechnology applied to the organ transplantation. Under de complexity perspective, trachea is a simple organ. However, doors will be opened to the transplantation of com complex organs, artificial by nature;
• It is an important advance in the field of personalized medicine, since the artificial trachea was custom made.

Besides, artificial organs are superior to donor organs:

• They can be obtained more quickly than a donor organ can often be found;
• Are grown from the patient’s own cells;
• They do not require dangerous immunosuppressant drugs to prevent rejection (rejection is out of the equation).

Furthermore, one of the technologies intensively studied in nanotechnology in regenerative medicine and tissue engineering is nanoscale topography and nanoscale engineering of the surface of cells and tissues. These techniques employed are several, and include:

• Nanolithography;
• 3D printing.

I strongly believe that very soon it will be possible to print in 3D the mold of a customized scaffold for regenerative medicine and tissue engineering purposes.

This will open doors to the capability of 3 D printing the scaffold itself.

3D printers will also be available.

Finally, the nanotechnology-based tissue engineering, regenerative medicine and organ transplantation will be a routine practice of nanomedicine.