An ultrasensitive electrochemical detection of tryptase using 3D macroporous reduced graphene oxide nanocomposites by one-pot electrochemical synthesis.

In this study, we introduce an ultrasensitive and stable sensing platform based on gold nanoparticle decorated 3D reduced graphene oxide - carbon nanotube nanocomposites (GNP/CNT/rGO) for detection of tryptase (Tryp), which is a potential biomarker within nasal secretions for allergic rhinitis (AR). The GNP/CNT/rGO on the glassy carbon electrode (GCE) was fabricated through single-step one-pot electrochemical co-reduction and deposition. The GNP/CNT/rGO exhibited excellent electrocatalytic activity as the working electrode compared with bare GCE, GNP/rGO and CNT/rGO on GCEs. The enhanced performance of GNP/CNT/rGO may be attributed to 3D macroporous structures, which may provide increased surface area, faster charge transfer and lower mass transport resistance, as well as high electrocatalytic activity and good biocompatibility due to GNP. A GNP/CNT/rGO-based sandwich-type electrochemical immunosensor was fabricated for detection of Tryp, which requires high sensitivity and specificity. The GNP/CNT/rGO-based immunosensor exhibited a detection range from 100 pg/mL to 100 ng/mL, a detection limit of 50 pg/mL and a sensitivity of 1.64 μA/(ng/mL). This immunosensor possessed high selectivity, excellent reproducibility (RSD 2.1%) and high stability over approximately 1 month. Therefore, we expect that the GNP/CNT/rGO and the modified immunosensor will be useful tools for detecting Tryp in nasal secretions for clinical diagnosis of AR.