A novel electrochemical strategy for NT-proBNP detection using IMFET for monitoring heart failure by saliva analysis

Heart failure (HF) is a chronic cardiovascular disease that represents main cause of mortality worldwide, particularly for elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) was identified as the gold standard biomarker for HF diagnosis and therapy monitoring. Presently, saliva analysis represents an emerging and powerful tool for clinical applications and electrochemical immunosensors have shown their potential in Healthcare applications as selective and reliable systems for detecting clinical biomarkers. This work presents the detection of NT-proBNP in saliva samples by an immunologically modified Field effect Transistor (IMFET). TESUD ((11-triethoxysilyl) undecanal) was used as cross-linker to immobilise anti-NT-proBNP antibody onto the device. Our IMFET that was then tested in different matrices (e.g. phosphate buffered saline (PBS), artificial saliva and human saliva) using electrochemical impedance spectroscopy (EIS), and it resulted selective to NT-proBNP with good sensitivity (detection limit of 0.02 pg/mL) and a wide linear range (0.02-1 pg/mL and 0.5-20 pg/mL). Finally, NT-proBNP concentration in ten saliva samples was determined by performing the standard addition method. An enzyme-linked immunosorbent assay was used for confirming IMFET results, highlighting both IMFET accuracy (analyte recovery of 99 +/- 8%) and precision (coefficient of variation always <10%), and supporting the suitability of the device for determining salivary NT-proBNP.

Automated summary

Heart failure is a chronic cardiovascular disease that is a major cause of mortality globally, especially for the elderly. N-terminal pro-brain natriuretic peptide (NT-proBNP) has been identified as the gold standard biomarker for diagnosing and monitoring heart failure. Saliva analysis has emerged as a powerful tool for clinical applications, and electrochemical immunosensors have shown potential in detecting clinical biomarkers. This study developed an immunologically modified Field effect Transistor (IMFET) to detect NT-proBNP in saliva samples, demonstrating good selectivity, sensitivity, and accuracy.