Dual-mode portable electrochemical aptasensor for monitoring urinary neutrophil gelatinase-associated lipocalin (NGAL) biomarker

Abstract

Neutrophil gelatinase-associated lipocalin (NGAL) is significantly released in the serum and urine of acute kidney injury (AKI) patients as early as 2 h after the onset of renal damage, making it a potential candidate as an early biomarker for AKI monitoring and prognosis. An electrochemical aptasensor for NGAL detection was developed within a wide linear range of 5.0–320.0 ng/mL in PBS solution and a limit range of 5.0–25.0 ng/mL in artificial urine. Limits of detection (LODs) of square wave voltammetry (SWV) mode in PBS and artificial urine were at 0.81 and 4.59 ng/mL, respectively, while electrochemical impedance spectroscopy (EIS) measurements were observed at 0.48 and 5.27 ng/mL in PBS and artificial urine samples, respectively. Particularly, the dual measurement mode integrated with a multiple linear regression (MLR) model achieved an improved LOD of 3.27 ng/mL in urine matrix. NGAL aptasensor offered admirable recovery performance in a range of 93.0% and 126.0% with the relative standard deviations (RSDs) between 1.162% and 4.625%. The aptasensor was highly selective for NGAL across urinary matrices, while it tolerated potential interferences (i.e., IGFBP-7, BSA, ascorbic acid, and glucose) and offered stable performance for up to 14–21 days of storage. Its label-free, portable, and sensitive performance makes it a promising candidate for NGAL point-of-care testing (POCT) applications, enabling rapid and reliable detection of AKI status in clinical and field settings.