Development of a Biodegradable Microneedle-Based Sensor with NFC Communication for Dissolution Monitoring on Human Skin

The advancement of drug delivery techniques has been crucial in enhancing drug efficacy, patient comfort, and safety. While various routes such as oral, parenteral, and transdermal drug delivery have been explored, each presents unique advantages and challenges. This thesis focuses on transdermal drug delivery (TDD) and, specifically, the use of microneedle (MN) technology to overcome the limitations posed by the skin barrier. MNs provide a non-invasive, pain-free method for delivering drugs across the skin layers, offering improved bioavailability and controlled dosage delivery. All five main types of MNs—solid, coated, hollow, hydrogel, and dissolvable— have their respective advantages and limitations in drug delivery applications. Dissolving microneedles (dMNs) stands out as a promising solution due to their ability to release drugs upon exposure to interstitial fluid, eliminating sharp waste and simplifying fabrication processes. However, challenges such as limited dosage control and difficulty in assessing needle dissolution post-application require the development of a sensor to monitor the dissolution state and rate of dMNs. The thesis proposes and implements a sensor integrated with dMNs, aiming to optimize drug delivery accuracy and control. Exploiting Near Field Communication (NFC) technology, the sensor transmits data to a reader device, enabling remote monitoring of drug release kinetics and skin penetration status. Analyses and tests were carried out to optimize the fabrication process and characterize both the dMNs and the sensor, with the aim of enhancing the performances of the final integrated system. Mathematical models and simulations enable sensor optimization, culminating in the integration of the sensor with a printed circuit board (PCB) and NFC tag for wireless data transmission. The electrical resistance of the sensor, designed as a trace sputtered onto the dMN array, increases as the needles dissolve, facilitating real-time monitoring. Notably, the sensor's voltage readings across the array not only indicate needle dissolution but also distinguish between whether the needles have penetrated the skin or not. This breakthrough in monitoring capabilities significantly enhances drug delivery accuracy and enables precise control over dosage delivery. Farther studies could optimize the sensor design and develop a user-friendly interface to enhance system performance. This thesis contributes to the advancement of TDD by introducing a novel sensor-enabled approach to enhance drug delivery accuracy and monitoring, paving the way for safer, more efficient transdermal drug administration for both patients and scientists during the R&D phase.