Researchers at Washington University in St. Louis have developed a new calcium nanoparticle to stop the growth and metastisis of tumors. In order for cancer cells to grow and spread, they often lower their pH to escape the surrounding extracellular matrix. Using this information, a research team led by Avik Som, an MD/PhD student, and Samuel Achilefu, PhD, utilized calcium carbonate to raise pH. When calcium carbonate is mixed into water, it can cause the pH to rise up to ~9 which is harmful to humans; however, when injected into the body, it only raises the pH to ~7.4. Calcium carbonate was also chosen due to the fact that both calcium and carbonate are native molecules to the human body as opposed to many other popular material choices such as gold or silver.
Developing a new nanoparticle has not been easy. The group overcame many challenges when trying to design these nanoparticles such as the overly large size of naturally found calcium carbonate crystals. Through some collaborations, the team was able to develop a method using polyethyleneglycol-based diffusion to generate 20- and 300-nanometer-sized calcium carbonate. Furthermore, the group was able to successfully inject these nanoparticles into a mouse model of fibrosarcoma on a daily basis, which resulted in halted tumor growth. Once the treatment was stopped, the tumor began to grow again. In the future, the team plans to optimize the dosage as well as improving ways of delivering the drug.
Here’s Avik Som, an MD/PhD student at Washington University in St. Louis, talking about his research:
Study in journal Nanoscale: Monodispersed calcium carbonate nanoparticles modulate local pH and inhibit tumor growth in vivo