3D-printed multiplex system for electrochemical determination of yellow fever antigens and antibodies

Clinical diagnosis of yellow fever (YF) infection faces drawbacks due to symptoms similarities with other diseases and lack of specialized laboratories in remote areas. Thus, miniaturized platforms for determination of YF biomarkers are essential to guarantee the accurate identification of the infection. In this study, a 3D-printed multiplex system was proposed for the determination of the YF virus protein (YFV) and antibodies against the YF virus (Ab-YF). For that, an electrochemical cell containing six 3D-printed working electrodes, modified with electrochemically reduced graphene oxide, was employed. The biorecognition layer was assembled by a one-step approach, for label free determination of the respective biomarkers through immunocomplex formation, using square-wave voltammetry. The system enabled the analytes determination in diluted serum samples: for Ab-YF, the linear dynamic range was from 1.0 to 10 μg mL^-1, and qualitative determination of YFV was achieved from 0.5 to 10 μg mL^-1. In both cases, a clear differentiation between the responses of diluted serum samples, positive and negative for the respective target, was achieved. Proper selectivity towards the target was confirmed by evaluating interference from species related to other viruses transmitted by Aedes aegypti (Dengue, Chikungunya, and Zika). Additionally, simulated serum samples from uninfected individuals, individuals in the early phase of infection, and individuals in the later phase of infection were successfully analyzed using the multiplex system. Therefore, the potentiality of the miniaturized platform was showed for the determination of YF biomarkers, which is a key feature regarding the illness diagnosis, as well as the patient treatment and progression.