A screen-printed carbon electrode immobilized MXene-gold nanoparticles composite detects creatinine in micro-volume of human serum samples

Abstract

Creatinine (CR), a non-protein nitrogenous compound, serves as an important clinical indicator for assessing renal function. This research reports the application of screen-printed electrodes modified with Ti₃C₂-based MXene-gold nanocomposites (SPCE/MXene/AuNPs) for the precise quantification of CR in human serum. The SPCE/MXene/AuNPs sensor leverages its interactions with CR to enhance redox electrochemical signals, leading to their amplified detection sensitivity. Under optimal conditions (pH 7.4), the SPCE/MXene/AuNPs sensor exhibited excellent analytical performance, with a linear detection range of 0.1–11 mg dL⁻¹, a high correlation coefficient (R² = 0.99), and calculated detection and quantification limits of 0.018 mg dL⁻¹ and 0.06 mg dL⁻¹, respectively. Additionally, these electrodes demonstrated minimal interference from common physiological compounds (glucose, ascorbic acid, glutathione, bilirubin, gentamicin, vancomycin, arginine globulin, histidine, urea, bovine serum albumin (BSA), and electrolytes [K⁺, Ca²⁺, SO₄²⁻, and Mg²⁺]). Furthermore, the developed sensor demonstrated excellent correlation (R² = 0.99) with the standard Jaffe method for CR assessment in human serum samples (n = 89) with a mean difference of −0.136 mg dL⁻¹ (95 % CI: 0.190 to −0.081 mg dL⁻¹) and significant agreement confirmed by paired t-test (p < 0.0001). Only four samples exhibited false negatives (3.58, 3.02, 9.50, and 11.25 %). The sensor retained 94.7 % of its initial response after 15 days at 4 °C, and reproducibility was confirmed via overlapping CV cycles. Our investigation demonstrates the potential of our electrochemical sensor for accurate and reliable CR measurement in complex biological matrices.