Electrochemical N-Acetyl-β-D-glucosaminidase Urinalysis: Toward Sensor Chip-Based Diagnostics of Kidney Malfunction

N-Acetyl-beta-D-glucosaminidase (GlcNAcase) is a valuable biomarker for kidney health, as an increased urinary level of the enzyme indicates cell damage within the renal tubular filtration system from acute or chronic organ injury or exposure to nephrotoxic compounds. Effective renal function is vital for physiological homeostasis, and early detection of acute or chronic renal malfunction is critically important for timely treatment decisions. Here, we introduce a novel option for electrochemical urinalysis of GlcNAcase, based on anodic differential pulse voltammetry at boron-doped diamond disk sensors of the oxidizable product 4-nitrophenol (4NP), which is released by the action of GlcNAcase on the synthetic substrate 4NP-N-acetyl-beta-D-glucosaminide (GlcNAc-4NP), added to the test solution as a reporter molecule. The proposed voltammetric enzyme activity screen accurately distinguishes urine samples of normal, slightly elevated and critically high urinary GlcNAcase content without interference from other urinary constituents. Moreover, this practice has the potential to be adapted for use in a hand-held device for application in clinical laboratories by physicians or in personal home health care. Evidence is also presented for the effective management of the procedure with mass-producible screen-printed sensor chip platforms.