Jiarui Li, Wenli Zhu, Kaxi Chen, Fengling Tian, Mengxia Li, Yali Yuan, Jinfang Nie, Wenyuan Zhu, Lang Zhang, Yun Zhang
This work describes a label-free colorimetric immunoassay that initially integrates rolling circle amplification (RCA) with Tyndall effect (TE) characteristics of nucleic acid colloids. Using only a laser pointer and a smartphone, it achieves instrument-free protein quantification with 13-fold higher sensitivity than the conventional optical ELISA.