MXene bands back from space

MXene in LEO was one of 13 Polish experiments in the field of technology, biology, medicine, and psychology designed by Polish scientists and engineers and carried out by astronauts during Axiom Mission 4. The Polish, technological and scientific part of the mission was called IGNIS. “In LEO” in the name of the experiment refers to the Low Earth Orbit.

In turn, MXenes are a family of ultrathin nanomaterials, i.e. their thickness does not exceed 100 nanometres, which is a size that is definitely invisible to the naked eye. The materials were discovered only several years ago and AGH University researchers have been studying them since 2018. They are created with the use of transition metal carbides and nitrides derived from MAX phases. MXenes are very good electicity conductors, and because of their properties, they enable extremely precise measurement data to be obtained. Of their various properties, a particularly significant one is the change in electrical resistance that occurs when they undergo deformation (such as bending). When connected to the right measuring circuit, the changes can be recorded as changes in voltage or current at the electrodes. In addition, many of them are biocompatible; thus, scientists are hopeful that one day they will be used in wearable sensors, or even implants. All of these features make MXenes perfect candidates for use in modern sensors, for example in biometrics. In the case of the experiment by AGH University researchers performed on the ISS, the MXenes were created from layers of titanium carbides. According to scholars from AGH University, they can be used to measure pulse rate.

For this to work, the nanomaterial would have to adhere closely to the skin, e.g. to the wrist. Then, the blood pulsing through the veins would change the MXene's deformation, and the signal could be transmitted to the equipment and read by researchers. That is the reasoning behind the printing of MXenes on a specially-designed band.

Solid base

The material of choice for the production of the bands was bacterial cellulose, a biomaterial composed of bacteria-made fibres. It is light, elastic, insoluble in water, and very absorbent. It also absorbs and neutralises sweat. To increase its durability, the scientists decided to enhance it by adding glycerine. A great advantage of bacterial cellulose is its environmentally friendly production process, as its carbon footprint is very small. It is surely better for the environment than the production of plant cellulose. The sole problem is the large consumption of water. When bacterial cellulose is produced, the water is acidified and becomes toxic, which means that it requires proper disposal. Potentially, it would be worth using it for energy production. The scholars claim that due to the simplicity of the production process, which does not require advanced apparatus, such a material could be produced directly during a mission on a space station.

As emphasised by Dr Agata Kołodziejczyk during a talk in the series AGH SCIENCE meetings, since the material was to be taken to the space station for the first time, it had to undergo detailed tests to confirm its safety (e.g. whether it causes allergic reactions) and its ability to remain stable in extraterrestrial conditions.

Ultimately, all tests, including biocompatibility tests, were successful and, thanks to the efforts of all scientists involved in the experiment, the material was accepted by the European Space Agency and NASA and could be tested by Sławosz Uznański-Wiśniewski under space conditions. The use of MXenes and the cellulose band is far superior to the pulse-monitoring devices popular on Earth, which are LED-based and often prove unreliable in space.

The space effect

The aim of AGH University researchers during the space mission was to study how the nanomaterial behaves under microgravity and cosmic radiation conditions, i.e. assessing its environmental stability and  verifying its potential for use in monitoring human health. As the materials had not been tested on a space station before, the researchers had to check whether they remain stable, whether their properties change, and whether the conditions affect the way in which they take measurements. What was also essential was to test them in practice, to see whether it is actually possible to monitor the astronaut’s heartbeat with the use of the band.

The first part did not require any involvement of the astronaut, as the MXenes were placed in a specific location on the International Space Station, where they collected data on living in space conditions. As far as the second part of the plan is concerned, Sławosz Uznański-Wiśniewski took six bands to the orbit; each of them had to be tested twice. After putting them on, the astronaut was supposed to wear the wristbands for some time, keeping your arm in one position, but also perform a specific sequence of wrist movements. This will enable researchers to determine whether movement affects the accuracy of the measurement and whether measurement is even possible when the test subject moves their hands. To compare the data collected in microgravity with the data obtained on Earth, the team of researchers had to simultaneously carry out identical tests in a laboratory at AGH University.

Positive results

Stability test data has been collected, the astronaut's pulse and wrist movements have been detected, the wristbands have returned unscathed, and publications are in preparation. Preliminary data on the device’s sensitivity and the details of the results obtained are very promising. They may even provide more information than anticipated. In turn, during one of AGH Science meetings, Dr Agata Kołodziejczyk shared that  she did not notice any signs of decomposition or contamination on the bands after returning from orbit, nor did she detect any odours that could indicate the growth of bacteria, fungi, or mould.

The first official reports with an in-depth analysis of the experiment data are to be expected in the first half of 2026. However, the researchers involved in the project on the part of AGH University emphasise that the first profound effects can already be observed. The researchers have gained a great deal of experience in terms of the work on such large, international projects, an in-depth understanding of the entire formal process, and have established many valuable partnerships that will bear fruit in the future.

The future looks promising

MXenes have the opportunity to become the first step in the creation of a new generation of devices. Above all, they can be a key component of lightweight and precise sensors, characteristics that are particularly desirable in sensors used during long-range manned space missions. Due to the special properties of the MXenes used at AGH University, they can have a wide range of applications and be useful on Earth. Currently, the use of wristbands is being tested for suitability to monitor the health of cardiac patients in the Upper Silesian Medical Centre. The researchers also cooperate with the Polish Society for Surgery of the Hand to apply MXenes in physiotherapy after wrist or hand surgeries. In addition, it can be assumed that in the future wristbands could be used to monitor the health of people with chronic diseases.

At AGH University, the project is coordinated by Dr Shreyas Srivatsa, and the team members are: Prof. Tadeusz Uhl, Dr Agata Kołodziejczyk, Dr Krzysztof Grabowski, Dr Dagmara Stasiowska, Dr Darukesha Baraduru Hirematada, Wojciech Guziewicz, and Sławomir Rudawski. The form of the wristband was designed by students of the Faculty of Industrial Design at the Jan Matejko Academy of Fine Arts in Kraków under the supervision of Professor Michał Kracik. Based on guidelines from AGH University scientists and in line with the principles of industrial design, they designed a band that is easy to put on under microgravity conditions.