Optogenetics for diabetics

Scientists have developed smartphone-controlled cells that deliver insulin to the blood

Anastasia Krasnianskaya, Geektimes

Smartphones can already monitor homes and cars, as well as diagnose diseases. A group of Chinese and Swiss researchers proposed to shift the control of artificial cells implanted in the body to produce insulin to a smartphone. People with diabetes are forced to inject themselves with insulin regularly. A new device tested on mice may someday eliminate the painful need to use needles.

Cell therapy is a new radical promising treatment option. The idea is to create by genetic engineering such cells that are able to secrete the necessary medicinal substances and implant them into the body... For example, white blood cells were forced to fight cancer, HIV and other diseases. Hundreds of cell therapies are undergoing clinical trials, although so far none of them are controlled from outside the body.

The researchers demonstrated a smart closed-loop system in which a digital glucose meter transmits data on the blood glucose level of mice to a smartphone. The smartphone processes the data and sends a signal to the implanted cells to deliver insulin. Less than two hours after the activation of the cells, the blood sugar level of the animals stabilized.

It would be impossible to create such a tool without optogenetics, a field of research that uses light–sensitive proteins to regulate biological activity in the body. This method has been proposed for the treatment of a number of diseases, including Parkinson's disease and schizophrenia. The first human clinical trial of achievements in the field of optogenetics, currently underway, is designed to restore the vision of a patient with retinitis pigmentosa, a degenerative eye condition that leads to blindness.

As part of an experiment with diabetic mice, at the first stage, the researchers changed human cells using a light-sensitive gene that was found in plants and causes cells to produce insulin on a signal. The scientists then injected photosensitive bacterial proteins into mammalian cells. Under the influence of a distant red light with a wavelength of about 730 nm, the protein activated a sequence of genes that caused cells to produce insulin. 

Here and below are the drawings from the article by Shao et al. Smartphone-controlled optogenetically engineered cells enable semiautomatic glucose homeostasis in diabetic mice (Science Translational Medicine, 2017).

After a successful experiment, the researchers created a device the size of a ruble coin in which the receiving coils surround a hydrogel with built-in cells with red LEDs. These devices were implanted under the skin of mice with diabetes. When the external coil wirelessly turns on the LEDs by electromagnetic induction, their light activates the cells that produce insulin.

The team of scientists did three things to remotely control the cells: a customizable Bluetooth-enabled blood glucose meter, an Android smartphone app, and an intelligent control unit that regulates the transmitting power of the coil. 

When researchers place mouse blood samples on a glucose meter, it sends measurements to a smartphone via Bluetooth. The application compares these levels with a preset threshold, then transmits a signal to the control unit to turn on the power transmitter coil, which causes the diodes to glow long enough for the implant to deliver the right amount of insulin.

The application allows the user to determine how bright the LEDs should glow, and how long they will control the amount of insulin in the cells. A Bluetooth transmitter connected to a blood glucose meter can send a notification to a smartphone when the sugar level is too high and automatically turn on insulin production.

The level of glucose in the blood of animals usually decreased to normal levels within two hours after the procedure. The system maintained the concentration of glucose in the blood of mice for 15 days without any side effects. However, the researchers are confident that it is necessary to further investigate how much longer operation and the frequency of implant replacement affect the body and the operation of the device.

The system as a whole also requires significant refinement. The smartphone app actually "communicates" with the server, which is something like a smart home center that includes an induction coil surrounding mice with an electromagnetic field. Electromagnetism activates the LEDs in the implant, so it only works when the mice are near the transmitter, which can be a problem for any diabetic who wants to leave the house at least sometimes.

In addition, the current design still requires the use of a needle to check blood sugar levels. Future versions of HydrogeLED, as the researchers suggest, are designed to solve both problems. One of the authors of the study, Haifeng Ye, suggests the presence of a built-in glucose meter that monitors the patient's blood sugar level 24 hours a day, automatically starting battery-powered LEDs when insulin is needed.

Scientists have a long way to go before HedrogeLED can be tested on humans. First you need to test on more animals – the current version of the technology has been tested only on groups of five to six mice, as well as on larger animals, such as dogs or monkeys, for two to three weeks. Researchers should also make sure that all materials used are safe and do not stimulate immune responses. 

Portal "Eternal youth" http://vechnayamolodost.ru  28.04.2017