Smartphones can already control homes and cars, and diagnose diseases. Chinese and Swiss researchers now show that a smartphone can command engineered cells implanted in diabetic mice to produce insulin.
The researchers demonstrated a clever closed-loop system in which a digital glucometer transmits data on the rodents’ blood glucose levels to a smartphone, which processes the data and then signals the implanted cells to deliver insulin. This is a step towards “a new era of personalized, digitalized precision medicine,” says Haifeng Ye of East China Normal University, who led the work reported in Science.
Cell-based therapies are a radical new medical treatment option being investigated by researchers. The idea is to turn cells into disease-fighting weapons by engineering them to produce therapeutic chemicals and proteins that they would churn out once implanted in the body. Living white blood cells, for instance, have been designed to fight cancer, HIV, and other diseases. Hundreds of cell therapies are undergoing clinical trials. But none can be controlled from outside the body.
Ye and his colleagues have come up with an innovative way to add smarts to cell-based therapy. They chose diabetes as the target disease.
They initially inserted light-sensitive bacterial proteins into mammalian cells. When exposed to far-red light (wavelength of about 730 nanometers), the protein activated a genetic pathway that caused the cells to produce insulin.
After that success, they team made dime-size devices in which circular power-receiving coils surround a hydrogel that is embedded with the engineered cells and far-red LEDs. These devices were implanted under the skin of diabetic mice. When an external transmitting coil wirelessly switches on the LEDs via electromagnetic induction, their light triggers the cells to produce insulin in the animals.
The team made three things to remotely control the engineered cells: a custom-engineered Bluetooth-active glucometer, an Android-based smartphone app, and an intelligent control box that controls the power-transmitting coil.
When the researchers place mice blood samples on the glucometer, it sends measurements to the smartphone via Bluetooth. The phone app compares these levels to a pre-set threshold, then signals the control box to turn on the power-transmitter coil, which switches on the LEDs long enough for the cell implant to deliver the right amount of insulin.
The animals’ blood glucose typically went down to nondiabetic levels within two hours of irradiation. The system maintained the blood glucose concentration in mice for 15 days without any side effects. After that it could be replaced, Ye says, but “a much longer performance or replacement frequency of the implant needs to be further investigated in humans.”
One big limitation of the system is that it needs manual blood draws. Another is that the animals need to be close to the transmitting coil and be exposed to EM radiation to switch on the LEDs.
But a bit more engineering could yield a diabetes monitoring-and-treatment system that is fully automatic and portable. A continuous glucose monitor could send blood sugar measurements to the user’s phone. The phone would trigger a battery-powered LED wristband to shine light on the implanted insulin-producing cells.