Current Research

Sports Data Analytics...

Our experience working with athletes in performance previously on sweat analysis led us to go beyond individuals and dive into the sports data analytics. We are interested in predicting team and player performance and preventing injuries before they happen. Our inputs are sleep data (WHOOP straps), subjective athlete survey, metabolic conditioning tests (jumping on force plates), and strength conditioning data. We aim to use these information to create predictive algorithms to provide information to coaches.

Sweat …

Our sweat sensing research deals with determining hydration levels from human sweat. Through years of research, we proved that salt levels of human sweat can be detected in real-time by measuring the electrolyte content of the sweat. We developed theoretical models, designed wearable devices, and conducted human experiments over the course of a decade.

In 2015, we published the first real-time sweat sensing device in Applied Physics Letters (IF 3.52, Q1, H-Index 385), which was arguably the start of this unique approach in the sweat sensing field [Article link]. This was our first true interdisciplinary article where we worked with exercise physiologists and physicists. This paper was followed by the most important paper of our group that was published in Sensors and Actuators B: Chemical (IF 4.30, Q1, H-Index 159) [Article link]. A group of 10 researchers worked very hard in over six intense months composed of Electrical, Mechanical, and Computer Engineering undergraduate students, exercise physiologists, and athletic trainers to publish the first ever wearable sweat sensing watch. This article has been the most cited articles of our group according to Google Scholar (link).

Then something happened: A group of 14 PhDs from the University of California, Berkeley published an article in Nature that literally did everything we planned for the next five years. As we explored possible directions, we realized one opportunity: determination of the rate of sweat. This was never done before, mainly due to the very reason that it was extremely difficult to measure the slow motion of sweating. Our several months of fundamental theory studies paid off as we devised a way of revising an old technique of thermofluid testing into a microscale sweat rate analysis, which turned into a master’s thesis of Tashfin Iftekhar. We published this article in Journal of Applied Physics (IF 1.56, Q1, H-Index 283) in 2017 as the theoretical concept [Article link] and followed up with a complete wearable device in 2018 where we conducted the experiments at SHU with the help of Prof. Alicja Stannard from exercise science, which was published in Sensors (IF 2.68, Q2, H-Index 114), the field’s rising journal [Article link] and has been cited (link) by Nature and Sensors and Actuators A, trend-setting journals in the field.

We were also fortunate to publish a review article in 2018 on wearable sweat sensors [Article link]. Just to put it into context, we spent two years constructing the framework and discussing with the experts in the field. It was an honor to be invited to publish this review article in Electroanalysis (IF 2.85, Q2, H-Index 117).

In addition to developing wearable devices, we noticed there was a need for testing equipment for sweat sensor prototypes. Researchers have been struggling to find a standardized testing system for physiological activity monitoring prototypes. We worked on building a completely automated device to create artificial sweat and test a wearable sweat watch without any need of intervention. We published this research in 2019 in MDPI’s Electronics (IF 2.11, Q1, H-Index 21) [Article link]. Even though the application of this test platform seems to be in a narrow field, we believe the approach of computerized liquid mixing and pumping will find interesting applications by other researchers.

Dr. Kaya was interviewed on sweat sensor research that appeared on two online platforms; Fairfield Citizen Online in 2018 (link) and Boston University News Service in 2017 (link).

Advanced Materials...

In 2015, a Turkish professor, Dr. Bunyamin Sahin, joined our research lab at CMU as a visiting researcher. His expertise was creating nano-scale metal oxide structures. His goal was to find applications for his technique. Together, we revised and applied his established and recognized technique to sweat sensing. We first produced a very thin layer of copper oxide and proved that it had the potential to be used in sweat sensing devices, which was published in Elsevier’s Ceramics International (IF 2.09, Q1, H-Index 82) in 2015 [Article link]. We published two more articles in 2016 during his one year sabbatical in our lab while we improved our technique to specifically target sweat ions using the copper oxide (Applied Surface Science, IF 2.87, Q1, H-Index 147) [Article link] and further investigated the effects of process parameters on sensing properties of the devices (Microelectronic Engineering, IF 1.4, Q2, H-Index 85) [Article link].

Once Dr. Sahin returned to Turkey, we worked on a review article on metal oxide sensors and published it in one of the premier journals of materials science research in 2019; Materials Research Express (IF 1.15, Q1, H-Index 15) [Article link].

Our collaboration continued remotely as we continue exploring various ways of using metal oxides in sweat sensing applications (see publications).