Development of electrochemical methods to enzymatically detect lactate and glucose using imaginary impedance for enhanced management of glycemic compromised patients

Lactate is an important biological marker that can provide valuable information for patients who have experienced a traumatic injury. Additionally, when coupled with glucose, the severity and likely prognosis of a traumatic injury can be determined. Because monitoring various markers proves useful in diagnosis and treatment of trauma patients, monitoring both glucose and lactate simultaneously may be especially useful for diabetic patients who have suffered a traumatic injury. Previously, using electrochemical impedance spectroscopy (EIS), a sensor capable of measuring two affinity-based biomarkers simultaneously was demonstrated using the biomarker’s specific optimal frequency to develop a deconvolution algorithm, which allowed for the measurement of two biomarkers from a single signal. Herein, while developing an EIS lactate sensor, dual enzymatic biomarker detection of lactate and glucose via EIS was also attempted. Both biomarkers were validated individually with the lactate sensor being additionally validated on whole blood samples. The EIS lactate biosensor achieved a range of detection from 0 to 32 mM of lactate and the glucose sensor a range of 0–100 mg/dL of glucose, which are representative of the likely physiological ranges that trauma patients experience. However, the preliminary attempt of dual marker detection was unsuccessful due to suspected accumulation of reduced redox probe on the surface of the self-assembled monolayer (SAM). Individually, the optimal frequency of lactate was determined to be 69.75 Hz and that of glucose was determined to be 31.5 Hz. However, when combined onto one sensor, no discernable optimal frequency could be determined which again was suspected to be due to the accumulation of the reduced redox probe at the surface of the SAM.