A large number of people today suffer from diabetes. For these people, rigorous and constant glucose monitoring is vital. This is usually done using enzyme biosensors that check blood sugar levels. These devices often require the use of needles for sampling, which can be invasive, painful and lead to infrequent testing.

Therefore, there is now a growing demand for glucose monitoring devices that are easy and non-invasive for the patient. Advances focus on glucose monitoring in the patient's sweat, devising a less painful glucometer.

In this context, e-ring has been developed, an electrochemical ring made by FDM 3D printing with flexible material (TPU) that includes three electrodes made of conductive filament (conductive PLA). Scientists from the National and Kapodistrian University of Athens are the architects of this novel device, which only requires the use of a standard smartphone.

The electronic ring is modified with an electrodeposited gold film and is coupled to a miniature potentiostat that connects directly to a conventional smartphone, offering the possibility of non-invasive self-diagnosis of glucose levels in sweat.

Image 1: E-ring in operation. Source: Analytical Chemistry journal.

The researchers produced four different prototypes, all based on the same basic design and using the aforementioned materials. For their manufacture, they used a commercial 3D printer with a dual extruder, which allows the production of parts with two materials.

Image 2: E-ring 3D printed with a combination of TPU and carbon-loaded PLA. Source: Analytical Chemistry journal.

The development of the research is detailed in the article entitled "Smartphone-Addressable 3D-Printed Electrochemical Ring for Nonenzymatic Self-Monitoring of Glucose in Human Sweat" authored by Vassiliki Katseli, Anastasios Economou and Christos Kokkinos.

This is an example of how 3D printing is bringing innovations to the medical sector. Undoubtedly, 3D printing is playing a very important role alongside wearable electronics, and has become the focus of several research projects that are yielding very interesting results.