Workshop presentation at VLSI Symposium 2025

Jun-Chau will be presenting at the VLSI workshop: Recent Advances in CMOS Cellular and Molecular Biosensors. Please see program here: https://www.vlsisymposium.org/workshop/workshop2025_6/.

Title: Continuous Monitoring of Small Molecules Using Electrochemical Aptamer-Based Biosensors with CMOS Electronic Abstract: The ability to continuously monitor specific molecules over extended periods can provide fundamentally new insights into disease dynamics and the transition from a healthy to a diseased state. This capability can also drive the development of next-generation screening and detection tools. However, only a few biomolecules—such as glucose, oxygen, and dopamine—can currently be monitored in real time due to multiple limitations in existing biosensor technologies. In this presentation, we introduce a class of biosensors known as aptamers. Aptamers are synthetic antibodies composed of nucleic acids (e.g., DNA or RNA) that can specifically bind to target analytes in complex samples, including whole blood. Importantly, they can be engineered into aptamer switches, which undergo reversible structural changes upon target binding. By conjugating electroactive reporters to these aptamers, structural changes—correlated to analyte concentration—can be detected electrochemically. Because aptamer switches do not require sample preparation, they are well-suited for continuous in vivo monitoring of biomolecules. However, integrating these structure-switching aptamers with readout electronics presents unique challenges. We will first outline the biosensor requirements and present our circuit innovations to meet them. This will be followed by discussion on system-level integration with wireless capabilities tailored for wearable and implantable applications. We will also address challenges such as signal drift and biofouling. Finally, we will demonstrate successful continuous monitoring of small-molecule drugs, such as antibiotics and chemotherapeutics, in freely moving rodents.