Sensitive detection of exhaled breath condensate inflammation biomarkers using boron nitride nanosheet/gold nanoparticle hybrids

An ultrasensitive electrochemical immunosensor using boron nitride nanosheet/gold nanoparticle (BNNS/AuNP) hybrids was developed for exhaled breath condensate (EBC) interleukin-6 (IL-6) quantification. BNNS were synthesized by chemical vapor deposition and decorated with AuNPs. The BNNS/AuNP hybrids were characterized by SEM, TEM, XRD, Raman, XPS, etc., and deposited on screen-printed carbon electrodes. Anti-IL-6 antibodies were immobilized via EDC/NHS crosslinking. The immunosensor detected IL-6 by differential pulse voltammetry technique with a linear range of 0.01–200 ng/mL and a limit of detection of 5 pg/mL. The sensor showed high reproducibility and selectivity. Validation with spiked EBC samples demonstrated good accuracy (relative error <5%). The sensor was successfully applied to analyze IL-6 in EBC samples. The BNNS/AuNP hybrid immunosensor provides a sensitive platform for non-invasive EBC biomarker quantification in respiratory diseases.