About Micro-Na

Welcome to Micro-Na, a collaboration between McGill Biodesign and Professor Brambilla’s laboratory at Université de Montréal! Together, we are designing a hydrogel microneedle patch for the non-invasive monitoring of sodium levels.

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Our bodies require a healthy balance of electrolytes in order to function properly. Normal sodium levels in the blood hover at around 135-145 mM, and levels that fall below this range are characterized as hyponatremia. Hyponatremia occurs in 15-30% of hospitalized patients and often in people who have taken part in endurance sporting events. Depending on how severe it is, symptoms can range from headaches and confusion to seizures and even coma. Hyponatremia is typically diagnosed through invasive blood tests or urine sodium tests, both of which require lab testing with priority-based classifications and, thus, long turnaround time.

Microneedle patches are arrays of microscopic needles that can be applied to the skin in a minimally invasive fashion. While microneedle technology is still in its developing stages, it has potential for applications in drug delivery and biosensing for a variety of detections. We are particularly interested in exploring the exciting possibilities of what microneedle patches can do to facilitate the process of detecting sodium levels in the body.


Micro-Na is a swelling microneedle patch that is meant to give a fluorescent readout of sodium levels in the body when applied. The patch is composed of a specific hydrogel formulation that will swell and absorb interstitial fluid, the fluid found in spaces around cells. Studies have shown that the levels of ions in interstitial fluid are pretty well-correlated with the levels in blood. By loading our microneedle patch with a molecule that fluoresces in the presence of sodium, we can design a detection platform to indicate sodium levels in someone’s body.


For our microneedle patch, we selected a commercially available fluorophore called CoroNa Green, which is mostly used in studies of cell behaviour. While there is data available for the ability of CoroNa Green to detect sodium, we wanted to validate it ourselves before moving forward with it. After conducting selectivity and sensitivity tests, the results showed that CoroNa Green is a suitable fluorophore to detect sodium. We could then start on the design experiments!


To fabricate the microneedle patches and combine them with the CoroNa Green fluorophore, we decided to try an existing swelling microneedle composition with potassium or sodium and a composition without. We found that there wasn’t a major difference in how the patch turned out regardless of the composition, so we settled with the formulation that didn’t use sodium or potassium.

We also used a fluorophore loading technique currently used at the Brambilla lab, to determine an ideal loading time to maximize the amount of fluorophore transferred onto the patch while retaining the needles’ structural integrity. Based on the microscopy images of the loaded patches, we decided that the 60-second loading time was the best.

We’ve also tested the microneedle patch on pig skin prepared with known parameters to determine the patches’ ability. We noticed that the patches applied to the skin samples with higher levels of sodium had a greater fluorescence intensity. Some future work includes observing the fluorescence for a greater range of sodium levels to establish the microneedles’ accuracy and consistency in detecting sodium levels.

Future of the Project

We need to conduct further research to confirm the effectiveness and accuracy of the patch for detecting sodium levels, as well as quantify the reproducibility of our procedures, which can be quite challenging.

In comparison to traditional testing methods, microneedles present a more patient-friendly option for measuring levels of biomarkers like sodium in a non-invasive way with a simple application process. We envision that the use of this product could help reduce the amount of waste and energy that goes into a typical blood or urine test, as well as reduce the burden placed on healthcare providers by facilitating the process of monitoring patients. The microneedle patch is quite small, made of biocompatible materials, and requires a much smaller sample volume than lab testing currently used. The goal of our project is to improve the detection, and, consequently, the treatment of hyponatremia to address its $1.6 – 3.6 billion USD annual burden in the US. Overall, through the work that we’ve done with this project, we hope to contribute to the advancement of technologies for more accessible detection and treatment of relevant conditions within the healthcare system.

Team Leads

Lan Anh Hyunh

Lan Anh is currently in U2 Bioengineering and is interested in the fields of biotechnology and machine learning. During her spare time she enjoys playing the violin, archery, and reading.

Zahra Panju

Zahra is a Team Lead for Micro-Na, where she is involved in the creation of a hydrogel microneedle patch.

Zahra is a U3 Chemical Engineering student who loves to play tennis, cook new dishes, and go on long walks.

Watch to learn more about us!