Cardiogram for Instagram
How mobile devices turn into medical devices and entire laboratories
Oleg Lischuk, N+1
The ubiquity of smartphones allows many developers around the world to look for a variety of applications for these devices. One of the most interesting and useful areas of this kind is the creation of medical devices based on mobile devices. They allow patients to monitor their well–being without visiting a doctor, and medical specialists to carry out complex types of diagnostics "in the field" when bulky and expensive devices for visualization and laboratory diagnostics are unavailable for various reasons.
For every day
Relatively simple devices that turn a smartphone into a medical device have been on the market for more than a year, and there has been some competition between their manufacturers. Examples of such devices are portable electronic stethoscopes, cardiographs and glucose meters.
Stethoscopes
So, the private medical company Orlando Health produces a sensor connected to a smartphone-a HeartBuds stethoscope. In clinical trials, it was not inferior to the best traditional phonendoscopes in recording cardiac and vascular noises and significantly surpassed disposable devices.
HeartBuds not only reproduces auscultative sounds, but also displays their graphical display on the smartphone screen. Patients themselves can use the device by forwarding the results of listening to the attending physician.
A similar device developed in In Japan, it can not only register sounds, but also recognize respiratory diseases using the Respiratory Sounds Visualizer mobile application.
It should appear on the market in the near future.
Cardiograph
You can also use your smartphone to take an ECG. The AliveCor Kardia Mobile ECG device designed for this purpose is attached to the back cover of the smartphone and registers a cardiogram from the fingertips, analyzing it with a special application.
The system is designed primarily for the diagnosis of arrhythmias.
A version of this device compatible with Apple Watch has also recently appeared.
Tonometer
The CardioDock module is also designed for cardiac patients. It turns a smartphone into a portable blood pressure monitor – a device for measuring blood pressure.
It costs no more than conventional electronic tonometers, but is much more compact.
Blood glucose meters
Another medical use of smartphones is monitoring blood glucose levels. It is necessary for all diabetic patients who inject themselves with insulin. Portable blood glucose meters have long existed for self-analysis for blood sugar, but why do you need a separate device if a smartphone can handle this task? Therefore, developers such as MyStar, AkibaH and others have created and are improving glucometric systems for mobile devices.
They can be a nine-gram plug-in for the iPhone or a case in which, in addition to the device itself, there are test strips and scarifiers for blood sampling.
There are other versions of smartphone blood glucose meters.
Otoscope
CellScope has developed an Oto device that turns a smartphone into an otoscope – a device for examining the external auditory canal and eardrum.
It is available in user (it contains visual instructions for use) and professional (with a pneumotoscope for diagnosing middle ear inflammation) versions.
Ultrasound
Smartphones can also perform more complex tasks. For example, MobiSante produces a full-fledged ultrasound scanner for mobile devices.
Its MobiUS SP1 system weighs only 340 grams, but its capabilities are almost as good as "big" devices. And it costs significantly less.
On the way to the tricorder
Scanadu has set an even more ambitious goal for itself. She is developing a universal diagnostic device based on a smartphone.
The current version of the Scout device can register pulse, ECG, respiratory rate, blood oxygen saturation and body temperature using a compact sensor attached to the temple.
Field microbiology...
Unlike the listed "everyday" devices, mobile systems for the diagnosis of infections have not yet left the experimental stage. But this does not mean that there are no interesting developments in this area with a variety of working principles.
Mobile ELISA
For example, Columbia University has created a microfluidic system for rapid diagnosis of sexually transmitted diseases using a smartphone.
She is able to perform an enzyme-linked immunosorbent assay (ELISA) for HIV infection and syphilis in 15 minutes with one drop of blood. The system receives the energy necessary for operation from a mobile device.
Two hours and two dollars
Researchers from Harvard and colleagues have developed an even more universal system. It amplifies bacterial RNA by PCR and analyzes it by the complementary DNA "key". When the desired genetic material is found in the solution, the "key" inactivates DNA polymerase and stabilizes reporter DNA, which acquires a high fluorescent anisotropy, which is recorded by the device. The whole system consists of four two-centimeter plastic cubes on a detector substrate, it connects to a smartphone via Bluetooth.
A – principle of operation, B – cartridge for RNA extraction, C – diagnostic system, D – smartphone application. Park et al., Sci. Adv., 2016
The analysis, called polarization-anisotropic diagnostics, takes two hours. According to the developers, with mass production, the cost of one study will be only about two dollars.
Amplification in a thermocup
Another device for DNA diagnostics of infections using a smartphone, created in University of Pennsylvania, based on loop isothermal amplification (LAMP) of nucleic acids. The analysis is carried out in a conventional thermocup heated by a thermoelement made of an alloy of magnesium and iron.
The appearance of the device and the thermoelectric element. Shih-Chuan Liao et al., Sensors and Actuators B, 2016
Visualization of LAMP results in real time is carried out by recording the fluorescence of the sample. To do this, the developers have installed an excitation filter and an emission filter in the cover holder for the smartphone, which allow you to use the flash and the smartphone camera.
...and oncology
Rapid diagnosis of cancer in any conditions is no less important than the detection of infections. And in this area, their own developments are underway.
Not 3D, but D3
The attachments on the smartphone, which turn its camera into a microscope, will probably surprise no one. Researchers from Harvard and Massachusetts General Hospital went further and turned such a microscope into an experimental D3 (Digital Diffraction Diagnosis) system for detecting cancer cells in a tissue sample.
Scheme of operation of the D3 system. Hyungsoon Im et al., PNAS, 2015
To do this, the sample is incubated with microgranules that bind to tumor cells, after which it is placed under a microscope and photographed. After that, the application transmits the snapshot to the server, where the algorithm analyzes the diffraction pattern of the microgranule structure and gives a conclusion within an hour.
Rolling Ring
A team of scientists from Sweden and the USA has developed a mobile system for the diagnosis of certain forms of cancer by their characteristic DNA mutations. The identification of the desired mutant gene is carried out by the rolling circle replication method: a gene potentially containing mutations is cut out of DNA and applied to a substrate with short DNA "probes". In the presence of a mutation, the gene binds complementarily to the probe, as well as a fragment containing a fluorescent label, after which it is looped. The resulting ring DNA is amplified with the formation of such a number of tags, which is sufficient for registration with a fluorescent microscope connected to a smartphone.
A diagram of the device, as well as a description of the approach underlying the analysis of mutant DNA. Malte Kühnemund et al., Nature Communications, 2017
In the experiment, the system determined mutant DNA in femtomolar concentrations, and both isolated nucleic acid and an uncleaned tissue sample obtained during biopsy were suitable for analysis.
The future is coming soon
The number of medical developments based on smartphones is growing every year, and it is impossible to fit them all into one review (for example, we did not talk about plans to create a mobile infrared tomograph). One thing is clear: the telemedicine future, in which smartphone diagnostics and remote consultation in many cases can replace a real visit to the doctor, is just around the corner. As well as diagnostic laboratories that can be carried in a backpack.
Portal "Eternal youth" http://vechnayamolodost.ru
23.01.2017