Catheter-Electrode System for Continuous Aptamer-Based Sensing in the Rat Subcutaneous Space.

Electrochemical aptamer-based (E-AB) sensors can continuously monitor drug concentrations with high temporal resolution. While previous studies have successfully demonstrated in vivo molecular monitoring using E-AB sensors, they typically rely on custom-built probes fabricated through manual, labor-intensive processes. Constructing such probes requires substantial time, technical expertise, and precision, creating a high barrier to entry for researchers interested in the field of in vivo measurements. To address this limitation, we present an alternative fabrication approach that combines established device construction methods with rapid prototyping via additive manufacturing (i.e., stereolithography). This platform enables continuous molecular monitoring in the subcutaneous interstitial fluid (ISF) of rodent models. We selected ISF as a target fluid due to its growing recognition as a promising frontier for continuous molecular monitoring and its central role in current biosensor research. Our goal is to eliminate the most prohibitive steps in traditional fabrication, thereby reducing the skill threshold required for building functional E-AB probes. By improving the construction process, our methods should make the technology more easily adoptable by a broader range of research laboratories. Ultimately, we aim to broaden the use of E-AB sensors and accelerate development in the field of real-time, in vivo molecular monitoring.