Magnetic nanoparticles may be able to regenerate bone

December 1, 2014

Topic: orthopaedic surgeons, orthopaedic research

Scientists from Keele University and Nottingham University have discovered a new method that may be able to regenerate bone.

Scientists from Keele University and Nottingham University have discovered a new method that may be able to regenerate bone. The findings would be instrumental for orthopaedic surgeons and other physicians who work to help repair damaged bone.

Developments in stem cell research
The National Institutes of Health noted that all bones have skeletal stem cells that can help regenerate and repair bone. The cells are known as bone marrow stromal stem cells, which use bone marrow's stromal tissue to recreate bone throughout the body. The journal of Regenerative Medicine noted that much research has been conducted to try and determine how to harness and increase skeletal stem cells' power to help replace the bone and tissue lost in trauma, surgery, diseases and congenital effects. Researchers hope to do more work in vivo, or studies that test biological entities on living organisms such as animals or plants, as opposed to dead ones. Work is also underway to attempt to differentiate the stem cells into separate categories. These sections include osteoblasts, chondrocytes, neural cells, muscle cells and adipocytes. Yet researchers are having difficulty finding a way to keep the cells to remain stimulated so that different parts of bone can be repaired at the same time by multiple stem cells.

The study authors discovered that magnetic nanoparticles that are coated with targeting proteins can help trigger stem cells, which in turn cause bone growth. The researchers were also able to direct the cells right to the area of injury via remote control. Through this process they were able to mechanically force the cells to work on the bone and help repair it.

The current process 
There is a bone regeneration method currently used in the orthopaedic world. However, it is not nearly as effective. The treatment uses a graft from the patient. Yet this procedure is invasive, incredibly painful and requires a significant recovery period. This can also be difficult if the patient does not have healthy bone to begin with, which cannot be shared.

As a result of these difficulties, generating bone growth from stem cells has peaked scientists' and orthopaedists' interest. Stem cell research has been ongoing for years, with significant progress being made. However, there is one area that has yet to be developed. For years, scientists have been working to find a way to activate different stem cells so they can repair and rebuild significant portions of bone.

Scientists James Henstock, Ph.D., Kevin Shakesheff, Ph.D., and professor Alicia El Haj all led the study.

A more effective method
Henstock noted that there are alternative treatments to bone grafting that show promise for patients with bone injuries.

"Injectable therapies for regenerative medicine show great potential as a minimally invasive route for introducing therapeutic stem cells, drug delivery vehicles and biomaterials efficiently to wound sites," Henstock said in a statement.

Henstock stated that the researchers coated the magnetic nanoparticles in specific targeting proteins and controlled them using a remote, external magnetic field that was supposed to simulate exercise. The study authors hoped to figure out how the process affected the injected bone and its regeneration abilities.

The study was conducted using two different models: tissue-engineered collagen hydrogels and chicken fetal femurs. Both models showed an increase in bone development and density without causing stress or pain to the surrounding joints and tissue.

"This work demonstrates that providing the appropriate mechanical cues in conjunction with controlled release of growth factors to these injectable cell therapies can have a significant impact on improving bone growth. It also could potentially improve tissue engineering approaches for translational medicine," Henstock concluded.

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