Cystic Fibrosis (CF) is a genetic disease that affects the synthesis of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein causing breath impairment, lung infections, malnutrition and pancreatic insufficiency. Early detection of CF patients is done by newborn bloodspot screening (NBS) protocol. Disease confirmation takes place through the so-called “sweat test”, where the CFTR ability to excrete chloride is tested. The gold standard test consists on measuring the sweat chloride content after stimulation of sweat glands with pilocarpine through an iontophoretic process. The commercial equipment and consumables are costly and the test has to be performed by trained personnel; consequently, its use is restricted to highly specialized CF units of medium-high income countries.
POWERPATCH consists of a single-use patch to be applied on a patient forearm that yields a “positive” result upon abnormal conductivity levels of sweat - a parameter accepted for screening purposes. The patch contains a paper-based battery acting as conductivity sensor, a disruptive concept IP-protected. The sweat is absorbed in the battery core and starts generating power depending on conductivity. The patch combines the ease of use of a plaster, while providing a digital response with no further handling or treatment of the sweat sample. Therefore, the patch can enable an easy, rapid and ubiquitous screening tool in regional hospitals or clinics, allowing for an early identification of CF patients at an affordable cost.
After testing a first version of the patch with artificial eccrine sweat samples closely mimicking healthy and non-healthy conditions of CF patients, the sweat patch was evolved from a TRL4 (technology validated in the lab) to a TRL5 (technology demonstrated in a relevant environment) by performing a feasibility test at Barcelona Children’s Hospital Sant Joan de Deu (HSJD) during the project. The goal of the test was to prove the patch safety, its ability to absorb sweat from the patient’s forearm and the correct operation of the battery and the electronic module. Design changes were introduced on the patch design. : Trials on 10 healthy adults confirmed test safety – no skin irritation nor discomfort was reported – and efficient sweat collection – which resulted to be below the 30 min required by the gold standard. After this, 28 children – 14 CF patients and 14 healthy volunteers – were tested during summer 2021. The obtained results confirmed the patch correct operation (sensitivity 0.93 specificity 0.85) and set the basis to move forward to a future clinical study with a statistically significant number of individuals.
Moreover, along the market discovery process, we learnt that not all countries inside or outside the EU can afford to implement the CF gold standard sweat test in specialized units, which made it one of the applications we explored first. A preliminary market search revealed that our patch could become ubiquitous in general practitioner’s offices or regional hospitals, enabling a quick screening of symptomatic newborns and small children and therefore, provide them with an earlier treatment. The availability of a single-use sweat-stimulating patch to accompany the CF screening patch would turn our solution into a ubiquitous point-of-care device, which definitely would allow its deployment in small clinics and dispensaries. Moreover, a small customer discovery process among the national CF representative clinicians at European level revealed the possibility of adapting our patch to become an assessment tool of the effectivity of pharmacologic treatments for CF, an application niche scarcely explored to date due to the restricted access of medical staff to the gold standard sweat test. Preliminary studies report a diminution of chloride contents of patient’s sweat could be used as an evaluation of the effectivity of CFTR drug modulators. Therefore, the periodic monitoring of ionic conductivity of sweat during the first months of drug administration would allow clinicians to validate progress and even to adjust the dose. Besides, our patch can become a new screening tool for clinical areas such as pneumology or gastroenterology, where patients suffering an undiagnosed CF condition are first derived. Finally, the screening patch can also become a tool to evaluate dehydration status due to electrolyte loss in patients undergoing diarrheic processes or in athletes submitted to intense activity.
