Graduate student Nisarg Shah belongs to the new generation of researchers using the SBC Histology facility. He joined the lab of Paula Hammond, PhD, the David H. Koch Professor in Engineering, a chemical engineer who designs nanomaterials for biomedical applications and cancer therapies. One area of interest is specifically targeting therapies to bone cancers, including hard-to-treat bone cancers that commonly affect adolescents. Shah’s project, which involves a coating for biomedical implants to improve adherence to the bone, is also testing the feasibility of delivering therapeutics right to the bone.
“A major challenge in orthopedics is that implanted hips or knees can separate from the bone when the cement used to adhere them breaks down,” he explains. “We want to encourage new bone growth on and into the implant, creating a chemical and physical bond that can improve implant survivability.”
He coats the implants with nanoscale stacked layers of biocompatible polymers infused with different agents: calcium phosphate to attract bone stem cells to the implant; a growth factor (BMP-2) that signals the stem cells to become osteoblasts (new bone cells); and another growth factor (VEGF) that recruits new blood vessels, since bone tissue is highly vascularized.
The layers are designed to slowly break down in the watery environment of the body, releasing just the right dose of agents at the site where they are needed. Now, Shah needed histology to determine how well this system actually works in animals and whether it causes any adverse side effects in the body.