Others involved in the development include Sara Alvarez, a graduate student in Sailor's laboratory, and Austin Derfus, a graduate student of engineering in Bhatia's former UCSD laboratory. UCSD has filed several patent applications on the device, which is now in the process of being commercialized by the Hitachi Chemical Research Center in Irvine, Ca.
The design of the new device builds on a previous development in the UCSD laboratories of Sailor and Bhatia that allowed the scientists to maintain fully functioning liver cells in culture. While many cell types can be easily grown in culture dishes, normal liver cells are much more discriminating and quickly die when removed from the body.
But by designing a porous silicon chip with miniature wells similar to those in muffin tins, the UCSD researchers were able to mimic the extracellular matrix of the liver and keep the liver cells alive. On this chip, individual cells are contained within well-like structures, 2 to 1,500 nanometers in diameter, or no wider than a human hair, that promote the flow of nutrients and chemicals through the cell culture and filter out larger particles such as bacteria and viruses. This design effectively persuades the cells to behave collectively the way they do in a fully functioning liver.
The scientists write in their paper that in their experiments the Smart Petri Dish was able to detect changes in the cells exposed to toxins "before traditional assays are able to detect a decrease in viability, demonstrating the potential of the technique as a complementary tool for cell viability studies." In addition, they add, their method "is noninvasive and can be performed in real time, representing a significant advantage compared to other techniques for in vitro monitoring of cell morphology," that is, for monitoring cells in the laboratory, outside of humans or animals.