Researchers at University of Michigan have developed self-assembling polymer spheres that can carry live cells within their hollow insides. Starting as star shaped pieces, the polymers form into spheres, and in the process encapsulate cells for possible transplantation. When the polymer spheres are injected into the body they biodegrade, releasing the cells. Researchers hope that if the process is worked out correctly, the release of cells will happen at the precise target site.
From U of M:
The procedure gives hope to people with certain types of cartilage injuries for which there aren’t good treatments now. It also provides a better alternative to ACI, which is a clinical method of treating cartilage injuries where the patient’s own cells are directly injected into the patient’s body. The quality of the tissue repair by the ACI technique isn’t good because the cells are injected loosely and are not supported by a carrier that simulates the natural environment for the cells, Ma [Peter Ma, professor at the University of Michigan School of Dentistry] says.
To repair complex or oddly shaped tissue defects, an injectable cell carrier is desirable to achieve accurate fit and to minimize surgery, he says. Ma’s lab has been working on a biomimetic strategy to design a cell matrixâ€”a system that copies biology and supports the cells as they grow and form tissueâ€”using biodegradable nanofibers.
Ma says the nanofibrous hollow microspheres are highly porous, which allows nutrients to enter easily, and they mimic the functions of cellular matrix in the body. Additionally, the nanofibers in these hollow microspheres do not generate much degradation byproducts that could hurt the cells, he says.
The nanofibrous hollow spheres are combined with cells and then injected into the wound. When the nanofiber spheres, which are slightly bigger than the cells they carry, degrade at the wound site, the cells they are carrying have already gotten a good start growing because the nanofiber spheres provide an environment in which the cells naturally thrive.
During testing, the nanofiber repair group grew as much as three to four times more tissue than the control group, Ma says. The next step is to see how the new cell carrier works in larger animals and eventually in people to repair cartilage and other tissue types.
Link: Researchers inject nanofiber spheres carrying cells into wounds to grow tissue…
Abstract in Nature Materials: Nanofibrous hollow microspheres self-assembled from star-shaped polymers as injectable cell carriers for knee repair