Bioceramics: The Next Chapter of Clay

By Elizabeth K., 17, Metropolitan Washington Mensa

Silica and alumina are two of the most prominent elements in the Earth’s crust. They are also abundant in clay. Clay, whose plasticity when mixed with water and strength upon exposure to heat, has been valued for centuries. Whether it is the creation of functional pottery to store and cook food, the production of industrial bricks and tiles to strengthen housing structures, or the design of intricate pieces of sculpture, the use of clay has found its way into all areas and walks of human life. This simple material has transformed into the expansive field of ceramics, a term that encapsulates a group of materials represented by inorganic, typically nonmetallic solids that often consist of elements and minerals found in natural clay mines.

I have a passion for ceramics. I love the smooth sensation of clay under my palms when I am throwing (the process of shaping an object out of clay with a pottery wheel) and how I can transform a grey blob into a delicate piece of art. It is gratifying when ideas from my imagination become tangible objects but even more valuable when my work morphs into something I could never have imagined. However, there is so much more to ceramics than the act of creation. When I throw clay, I am often surrounded by classmates and friends, all working on their art as we chat, laugh, and talk, creating a deep sense of community in the art studio. It transports us from the physical world into a transcendental understanding and appreciation for art. This kind of environment is one in which the piece you end up with does not matter as much as the relationships and bonds you form with those around you.

In the latter half of the 20th century, advancements in chemical sciences spurred the unexpected yet transformative merging of science and art. This innovation stemmed from the newfound recognition that certain properties of ceramic materials could be used to strengthen the human body in the form of implants for use in dentistry and orthopedics. From there, scientists started the field of bioceramics and the emerging use of different bioceramic prostheses and implants. Nowadays, bioceramics are used for the repair and augmentation of bones, joints, teeth, eye lenses, and even to support the creation of artificial heart valves.

Although I have enjoyed working with clay since elementary school, a high school chemistry class sparked my interest in bioceramics. Since carbon and silicon are both abundant on our planet, they commonly form compounds and share electrons with other

elements, making single or multiple covalent bonds. Both carbon and silicon are in the same column on the periodic table, have similar densities, and share the same number of valence electrons. Carbon is present in multiple lifeforms and is important in biological metabolic processes. On the other hand, Silicon serves as a major component in computers and semiconductors.

Given the similarities in the chemical properties, it might not be shocking that silicon-based bioceramic materials are considered relatively nontoxic when they interact with human tissues. Accordingly, there are generally four types of interactions between bioceramic implants and human bones. The first one is inert — when the implant does not form a chemical bond with the bone. The second is porous and allows the in-growth of cells into the pores of the implant. The third is bioactive because a bioactive material of an implant undergoes chemical reactions in the body and creates a bonding of the material and the tissue at their interface. The fourth type is resorbable, as implants of this type gradually resorb or degrade while being replaced by newly formed tissue. Unlike the relatively straightforward process of wheel throwing, it can be quite challenging to ensure an effective strength and correct mechanical properties of implants intended to promote tissue regeneration.

Although the field of bioceramics is young, the rate of discovery and progress within it is thrilling. This unique intersection of two seemingly opposite fields creates an innovative step toward the future of bioengineering. When thinking of prosthetics and devices, metal is one of the main materials we visualize. However, metals are slowly being replaced with complex formations of seemingly simple, tissue-adaptive clay.

Millennia ago, humankind employed clay to satisfy basic needs such as storing food and building shelter. Today, the very same base material has even more potential. The emergence of bioceramics as an innovative and versatile field extends the scope of bioengineering possibilities and may be one of the keys to solving some of today’s trickiest problems. ■