DNA-engineered immunosensing platform for ultrasensitive detection of clinical protein biomarkers

Detection of protein biomarkers is crucial for early diagnosis, dynamic monitoring, and prognosis evaluation of various diseases. However, the surface immobilization methods of capture probes directly affect the detection performance of immunosensors. Herein, a DNA-engineered immunosensing platform (DEISP) for ultrasensitive detection of clinical protein biomarkers is presented, which employs DNA duplexes to immobilize capture antibodies on the sensing interface. This DNA-engineered immobilization approach not only firmly anchors the capture antibody with excellent biocompatibility, but also preserves its binding sites for target molecules. As proof of concept, DEISP was employed to detect the kidney injury biomarker neutrophil gelatinase-associated lipocalin (NGAL), the pro-inflammatory cytokine interleukin-6 (IL-6), and the cardiac troponin I (cTnI) associated with myocardial infarction, demonstrating remarkable sensitivity with limits of detection (LODs) of 0.025 pg mL^-1 for NGAL, 0.026 pg mL^-1 for IL-6, and 2.35 pg mL^-1 for cTnI, as well as a dynamic range spanning 7 orders of magnitude. Moreover, DEISP exhibits 91% accuracy in clinical serum and urine samples and a total assay time of 90 min. Furthermore, DEISP significantly minimizes sample volume and simplifies operational procedures while achieving ultrahigh sensitivity, highlighting its potential for point-of-care testing (POCT), multi-marker screening, and precision medicine.