A Plasmonic Fluor‐Lightened Microneedle Array Enables Ultrasensitive Multitarget Whole Blood Diagnosis of Anemia in A Paper Origami‐Based Device

Abstract This work reports a portable, origami‐type paper device with a plasmonic fluor‐labeled microneedle sensing module for the multiplexed quantification of anemia biomarkers in whole blood. Sequential steps, including serum separation, target enrichment, and multiplexed readout by a gel imager, are rapidly accomplished with the flexible and highly integrated device. The microneedle array enabled efficient sampling of trace targets from ng mL −1 to pg mL −1 level. Combined with the plasmonic fluor label, the signal is improved by ≈7.6 folds compared with the flat substrate‐based assay. The device is applied to simultaneously quantify hemoglobin (Hb), ferritin, folic acid (FA), and vitamin B 12 (VB 12 ), which are four anemia biomarkers distributed in different environments with different concentration ranges. Featured by the small sample volume (150 µL), short assay time (20 min), low cost (2 $), robust stability, and user‐friendliness, the device is promising for the rapid and accurate diagnosis of anemia in real practice.