Integrating silicon microchip technology with a network of tiny fluid channels, some thinner than a human hair, researchers at The Johns Hopkins University have developed a thumb-size micro-incubator to culture living cells for lab tests
The incubator’s microchannels, fabricated in soft silicone polymer material, allow researchers to easily insert and guide cells and nutrients during experiments, while the computer-controlled electronics keep the cells at the precise temperature that enables them to multiply and thrive. The tiny incubator’s transparent design makes it easy to view the cells through a microscope or camera equipment without disrupting the conditions that help the cells to flourish.
A gas-permeable membrane on the incubator allows the microsystem to exchange carbon dioxide and oxygen but keeps out bacteria that could contaminate the cell culture. If a cell colony grows too large, an enzyme can be injected into one of the microfluidic ports to detach and flush away surplus cells without destroying the primary cell culture.
The incubator’s small size provides several advantages, the researchers say. The unit can easily be moved to different microscopes, imaging devices or other experimental tools without jeopardizing the health of the cell culture. Its size and relatively low cost should allow biologists to run numerous experiments simultaneously in a small space. Because it can be powered by batteries, the micro-incubator could be used outside a traditional lab for field tests
the thumb-size system developed by the Johns Hopkins engineers is self-contained and requires no external heating source. A drop of liquid containing living cells is injected into a port and flows through one of the microfluidic channels. A nutrient solution — the cells’ food — is also added in this manner.
The cells gravitate toward and stick to the surface of the microchip. The chip contains a simple heating unit — a miniature version of the type found in a common toaster — and is equipped with a sensor that continually checks to make sure the proper temperature is maintained. For human cells, this is usually 37 degrees Celsius or 98.6 degrees Fahrenheit. The chip is connected to a computer that controls the sensing and heating process. The prototype is connected to a computer via a hard wire, but the inventors say a wireless version would be the next step.
