Deterministic Evolution of Aptamers via a Microfluidic-Integrated Robotic Platform Using Complex Exosomes as Targets

Exosome (EXO) membrane proteins are attractive biomarkers for liquid biopsy, yet their heterogeneity makes it difficult to develop reliable antibody-based recognition reagents. Aptamers provide high-affinity and highly specific alternatives through the systematic evolution of ligands by exponential enrichment (SELEX), but the nanosized EXOs introduce substantial separation challenges that complicate SELEX workflows. Here, we present DeteRministic Evolution of Aptamers via a Microfluidic-integrated robotic platform (DREAMbot), an automated system engineered to execute multiround EXO-targeted aptamer selection with minimal human intervention. DREAMbot integrates a programmable pipetting robot with deterministic lateral displacement sorting and lipid-assisted magnetic isolation, enabling the automated purification and recovery of EXO-binding aptamers from cell-derived vesicles and molecular contaminants. This robotic-microfluidic workflow faithfully reproduces aptamer enrichment while substantially reducing hands-on burden compared to manual SELEX. Using cell-derived EXOs as targets, DREAMbot identified aptamers with nanomolar dissociation constants and high specificity toward GPC3-positive EXOs from both cultured cells and human serum. With its modular robotic-microfluidic architecture, DREAMbot provides a practical and accessible framework for automated aptamer discovery relevant to liquid biopsy applications.