The human body is a wonderful biological machine in itself. One of the functions of the human body that stands out is its ability to self-heal. Any wound on the body heals with the given time and energy, depending on the severity of the wound as well as various other factors. But this healing process can be greatly sped up with the intervention of biomedical sciences. Bioprinting is one such method used by bioengineers and doctors to fasten the repairing process. Any repairing requires the base material, cells, in the case of the human body. Bioprinting uses growth factors, which is an essential of cell growth.
An international research team of engineers headed by Ibrahim T. Ozbolat, Associate Professor of Engineering Science and Mechanics, is using bioprinting with two growth factor encoding genes to repair bone defects in the skulls of rats. They used two different genes that encoded two different growth factors, namely, the gene encoding PDGF-B, a platelet derived-growth factor and gene encoding BMP-2, a bone morphogenetic protein. The former encourages the multiplication and migration of cells while the latter helps in the improvement of bone regeneration. These factors helped stem cells to migrate into the defect area which in turn helped the progenitor cells to convert to bone. As stated in the journal Biomaterials, they used a controlled co-delivery release of plasmids from a gene-activated matrix to promote bone repair. The team used plasmids to embed the DNA for the protein. Plasmids are ringlike loops of DNA that transport genetic information. The DNA starts producing the required bone growth enhancing proteins once it enters the progenitor cell. A device similar to an ink-jet printer was used to print the two genes onto a hole in the skull of a rat during surgery. The mixture used was created to release a burst of PDGF-B encoding gene in 10 days and a continuing release of BMP-2 encoding gene for five weeks.The rats that received bio printed genes with controlled release of BMP-2 encoding gene saw about 40% bone tissue creation and 90% bone coverage in six weeks compared to 10% new bone tissue and 25% bone coverage for rats with the same defect, but no treatment.
As stated by Ozbolat, “This method is better than simply dumping the growth factors. If we do that, the amounts of proteins are finite, but if we use gene therapy, the cells continue to produce the necessary growth factors.”
This method would greatly enhance the bone repairing process of the human body and would be a milestone in the field of medical sciences.
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