Paper-Based Tests with a Rapid Plug-and-Play Aptameric Switch for Metabolic Disease Diagnosis at the Point of Care

User-friendly and timely biomarker monitoring is essential for metabolic disease diagnosis and management. The aptameric switch has emerged as a promising tool in metabolite sensing but is limited in point-of-care (POC) diagnostics due to the lack of fast response capacity. Here, we report a rapid, generalizable aptaswitch that leverages the flanking region to accelerate switching kinetics via decreasing the reaction energy barrier for the metabolite assay and further develop two portable, affordable POC devices comprising the aptaswitch and paper-based assays including lateral flow strips and paper disc arrays for fast and accurate diagnostic tests of clinical samples. We demonstrate tunability and universality of the flanking aptaswitch using four affinity binders against different metabolites, exhibiting its easy reprogramming and modular plug-and-play capability for distinct target analytes. This aptaswitch outperforms conventional aptameric designs, achieving up to 5-fold and 4.6-fold improvements in reaction speed and sensitivity, respectively. In addition, the paper-based POC tests require 20-fold less sample volume compared to the analogous solution-based assay while keeping excellent sensitivity, specificity, and storage and batch stability. We also demonstrate high diagnostic accuracy (100%) of the paper-based POC device for phenylketonuria screening using both mouse model and human clinical samples, and the visually read, user-friendly result within 20 min highlights its potential for rapid POC diagnostics. This work advances aptamer sensing toward POC accessibility and represents a significant improvement toward cost-effective, widely applicable, more usable paper-based biosensors or POC tools.