When treating patients with certain diseases, including covid-19, it is important to monitor their blood oxygen levels Now, a new subcutaneous photosensitive sensor provides a new means, and one day it can also be used to measure substances in other blood
The technology is being developed in the laboratory of Professor David Kaplan at Tufts University in Massachusetts. It currently takes the form of a thin-film disc smaller than an American dime, which is surgically inserted under the surface of the skin - a bit like a tattoo.
The film consists of a permeable gel composed mainly of cellulose. Among them, cellulose is a protein extracted from silk. It not only has biodegradability and biocompatibility, but also does not change the chemical properties of the substances added to it.
In the latest study, the substance is a compound called pdbmap, which glows when exposed to near-infrared light - the greater the amount of oxygen in the surrounding environment, the shorter the luminescence time. According to its manufacturing method, the sensor will be innocuously dissolved in the body in a few weeks to a year.
In the test of the device, the scientists inserted the sensor into the mouse's skin, and then irradiated the position with near-infrared light through the mouse's skin. The sensor responds by emitting light, and the duration of the light accurately represents the oxygen level of the interstitial liquid around it - the oxygen level of the liquid reflects the oxygen level of the blood.
Although blood oxygen content can already be measured noninvasively by pulse oximeter, the researchers hope that after the further development of the sensor technology, it can also be used to measure the amount of other substances in the blood, such as glucose, lactic acid or electrolytes. At present, this measurement can only be carried out through blood samples or connecting patients with complex equipment.
Thomas Falcucci, a graduate student from Kaplan laboratory who developed the device, said: "we can imagine that tattoo like sensors under the skin can work in many cases. This is usually when people with chronic diseases need to be monitored for a long time outside the traditional clinical environment. It is possible to use subcutaneous sensor arrays to track a variety of blood components."
It is reported that this study was recently published in advanced materials.