Nanoconfined Polymer Dot Reactors for Ultrasensitive Monitoring of Diverse Metabolites and Point-of-Care Diagnosis
Yijun Liu, Peng Zhou, Zitong Yang, Yuxin Yao, Haoyu Gong, Yonghong Wu, Peixiang Li, Qin Shentu, Lubin Qi, Zongping Wang, Yating Xiao, Yifei Jiang, Xiaohong FangAbstract
Polymer dots (Pdots) offer high brightness and tunable electronic properties for point-of-care testing, but conventional sensing often suffers from inefficient stochastic interactions and limited adaptability. Here, we screened Pdots for interactions with the NAD+/NADH redox couple and identified PDFDP Pdots with an NADH detection limit of 2.41 nM. Coupling PDFDP Pdots with NAD+-dependent enzymes enabled detection of multiple metabolites through enzymatically generated NADH. Co-encapsulation of Pdots and enzymes within microreactors further enhanced signal transduction by spatial confinement. Combined with smartphone-based RGB analysis under UV illumination, the platform enabled micromolar detection of lactate, β-hydroxybutyrate, glutamate, alanine, and ethanol. The method was further demonstrated in sweat and urine samples, showing good agreement with established analytical methods and supporting its potential for portable metabolite monitoring and exploratory disease-associated analysis.