Bioelectrochemical metric based on developing a novel and intelligent chemometrics-assisted electrochemical biosensor for multi-enzymatic biosensing of creatinine

Creatinine (CT) is a breakdown product of creatine phosphate from muscle and protein metabolism. Healthy kidneys filter CT out of the blood. The CT exits body as a waste product in urine. High levels can signal kidney issues. The CT blood test measures the level of CT in the blood. This test is done to see how well the kidneys are working. Therefore, determination of CT in biological fluids such as blood is important. In this work, a novel biosensor was fabricated based on modification of a glassy carbon electrode (GCE) with multiwalled carbon nanotubes-ionic liquid (MWCNTs-IL) and immobilization of three specific enzymes including creatinine amidohydrolase (CNN), creatine amidinohydrolase (CRN), and sarcosine oxidase (SOX) onto its surface for determination of CT. Amperometric responses of the biosensor recorded at optimal conditions found by a central composite design (CCD) as an experimental design approach were modeled for exploiting first-order advantage by partial least squeares-1 (PLS-1), recursive weighted partial least squares (rPLS), least square-support vector machine (LS-SVM), principal component regression (PCR), continuum power regression (CPR), robust continuum regression (RCR), back propagation-artificial neural networks (BP-ANN), wavelet transform-artificial neural networks (WT-ANN), partial robust M-regression (PRM), discrete wavelet transform-artificial neural networks (DWT-ANN), radial basis function-artificial neural networks (RBF-ANN), and radial basis function-partial least squares (RBF-PLS), to select the best algorithm to assist the biosensor for determination of CT in blood samples. The RBF-ANN showed the best performance to assist the CNN-CRN-SOX-MWCNTs-IL/GCE for determination of CT ranging from 0.1 to 18 pg mL⁻¹ with a limit of detection of 0.015 pg mL⁻¹, a limit of quantification of 0.049 pg mL⁻¹ and a sensitivity of 3.81 μA pg⁻¹ mL in blood samples, and its results were in a good accordance with high-performance liquid chromatography (HPLC) as the reference method.