Flexible electrochemical biochip for multianalyte detection in childhood leukemia diagnosis

Biochips are small-scale devices capable of performing sensitive, real-time multi-analyte detection. In oncodiagnostics, these tools are of great interest due to their rapid response, simple architecture, low cost, and the requirement of small sample volumes. In this context, the present study describes the development and validation of self-assembled biochips using polypyrrole and graphene quantum dots for detection of childhood acute lymphoblastic leukemia (ALL). The most frequent oncogenes such as ETV6-RUNX1 and TCF3-PBX1, associated with the t(12;21)(p13;q22) and t(1;19)(q23;p13.3) translocations, respectively were targeted, as well as aggressive oncogenes, including KMT2A-AFF1 and TCF3-HLF, linked to t(4;11)(q21;q23) and t(17;19)(q22;p13.3). The biochips were fabricated using simple additive manufacturing techniques and consist of a three-electrode electrochemical system. All fabrication steps and bioactivity assays were characterized by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Each step was evaluated by atomic force microscopy and scanning electron microscopy. During biorecognition assays, electrochemical changes characteristic of detection were observed, including a decrease in anodic peak currents and an increase in system impedance. The biochips achieved detection limits ranging from 9 to 29 copies of the oncogenes using label-free detection in 15 min. Therefore, the biochips developed in this study exhibit promising characteristics for the diagnosis of clinically relevant oncogenes.