• Layered clay particles cause stem cells to become bone cells, as revealed by the formation of bone matrix (in red).

    Credit: Courtesy Khademhosseini Laboratory, Brigham and Women's Hospital

    Layered clay particles cause stem cells to become bone cells, as revealed by the formation of bone matrix (in red).
An examination of the human anatomy reveals the extent to which life has incorporated matter from the physical world from which it originated. In particular, I'm referring to the minerals found in our planetary crust that have been reassembled to form the human skeleton.

In his book A Thousand Years of Nonlinear History, writer Manuel De Landa describes this transference of matter in this way: "Soft tissue (gels and aerosols, muscle and nerve) reigned supreme until 500 million years ago. At that point, some of the conglomerations of fleshy matter energy that made up life underwent a sudden mineralization, and a new material for constructing living creatures emerged: bone... The human endoskeleton was one of the many products of that ancient mineralization."

Recognition of this connection between the geophysical world and human physiology has led to the development of new medical breakthroughs, such as the discovery that layered clay catalyzes the transformation of stem cells into bone cells. In a research effort published in Advanced Materials, scientists at Brigham and Women's Hospital (BWH) describe how synthetic silicate nanoplatelets—which comprise salts of silicic acids—can induce this development of bone cells without the need for additional bone-growing techniques.

"With an aging population in the U.S., injuries and degenerative conditions are subsequently on the rise," said biomedical engineer Ali Khademhosseini in a BWH press release. "As a result, there is an increased demand for therapies that can repair damaged tissues. In particular, there is a great need for new materials that can direct stem cell differentiation and facilitate functional tissue formation. Silicate nanoplatelets have the potential to address this need in medicine and biotechnology."

Silicate nanoplatelets are commonly used in industrial and commercial applications such as ceramic fillers and food additives. The BWH project is evidence of the more advanced potential of this material when applied to biological processes.

"Based on the strong preliminary studies, we believe that these highly bioactive nanoplatelets may be utilized to develop devices such as injectable tissue repair matrices, bioactive fillers, or therapeutic agents for stimulating specific cellular responses in bone-related tissue engineering," said biomedical engineer and first paper author Akhilesh Gaharwar. "Future mechanistic studies will be performed to better understand underlying pathways that govern favorable responses, leading to a better understanding of how materials strategies can be leveraged to further improve construct performance and ultimately shorten patient recovery time."

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.