Microcages stack up for regrowth of tissues

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Microcages fabricated on a 3D printer could serve as scaffolding onto which hard and soft tissue can regrow and could eventually lead to lab-made organs for human transplant.

Microcages
OHSU researchers have developed a 3D-printed technology that can be assembled like Lego blocks and help repair broken bones and soft tissue. Each brick is 1.5mm3 cubed (Image: OHSU)

The small, hollow bricks can regrow tissue better than today's standard regeneration methods, according to research published in Advanced Materials.

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"Our patent-pending scaffolding is easy to use; it can be stacked together like Legos and placed in thousands of different configurations to match the complexity and size of almost any situation," said Luiz Bertassoni, Ph.D., who led the technology's development and is an associate professor in the Oregon Health & Science University (OHSU) School of Dentistry and an associate professor of biomedical engineering in the OHSU School of Medicine.

Bertassoni partnered with colleagues from OHSU, University of Oregon, New York University and Mahidol University in Thailand to develop and evaluate the technology.

When stacked together, the microcages are designed to repair broken bones. According to OHSU, orthopaedic surgeons typically repair more complex bone fractures by implanting metal rods or plates to stabilise the bone and then inserting bio-compatible scaffolding materials containing powders or pastes that promote healing.

The hollow blocks of the microcage scaffolding system can be filled with small amounts of gel containing various growth factors that are precisely placed closest to where they are needed. The study found growth factor-filled blocks placed near repaired rat bones led to about three times more blood vessel growth than conventional scaffolding material.

"The 3D-printed microcage technology improves healing by stimulating the right type of cells to grow in the right place, and at the right time," said study co-author Ramesh Subbiah, Ph.D., a postdoctoral scholar in Bertassoni's OHSU lab. "Different growth factors can be placed inside each block, enabling us to more precisely and quickly repair tissue."

The small devices are modular and can be assembled to fit into almost any space. When piecing together block segments containing four layers of four-bricks-by-four bricks, the researchers estimate more than 29,000 different configurations can be created.

Bertassoni and colleagues also imagine their 3D-printed technology could be used to heal bones that have to be removed for cancer treatment, for spinal fusion procedures, and to build up weakened jaw bones ahead of a dental implant.

By changing the composition of the technology's 3D-printed materials, they envision it could also be used to build or repair soft tissues. With more research, they hope the modular microcage approach could one day be used to make organs for transplant.