Real-Time Lactate Detection in A Dynamic Environment Using Micrsensing Needles

Abstract

This study introduces a novel microneedle-based lactate sensor with SU-8 micropillar enhancement, designed for real-time monitoring in dynamic environments. Utilizing inkjet-printing technology, the sensor demonstrates enhanced sensitivity and a reduced limit of detection (LoD), addressing critical challenges in clinical applications like hemodialysis and patient monitoring in ICU. Design enhancements in the medical steel needle improve stress resistance during insertion, contributing to the sensor's reliability. The experimental findings demonstrate that the microneedle is capable of achieving a high level of linearity at 0.99, with a sensitivity of 3.38 µA mM⁻¹/mm⁻²–0.5 µA mM⁻¹/mm⁻² observed within the range of 0.1–0.5 mM and 1–10 mM, respectively. Meanwhile, the microneedle exhibits a low limit of detection (LoD) of 0.01 mM when tested in phosphate-buffered saline (PBS) with varying lactate concentrations. Moreover, it demonstrates a linearity of 0.98, sensitivity of 1.13 µA mM⁻¹ mm⁻², and the same LoD of 0.01 mM in urine. The sensor maintains its performance at flow rates up to 500 mL min⁻¹. Overall, this flexible and inkjet-printed lactate sensor represents a significant advancement in real-time clinical monitoring technology.