Guanine quadruplexes (G4s) are nucleic acid structures present in diverse regions of the genome, such as telomeres and transcription initiators. Recently, the different biological roles of G4s have been evidenced as well as their role as biomarkers for tumors or viral infections. However, the fast and efficient detection of G4s in complex matrices remains elusive. In this contribution, by using long-scale molecular dynamics simulations, we propose the design of a biosensor based on organic field-effect transistors recognizing G4s. In particular, we show that the interaction of the G4s with the biosensor is translated into a change in the charge density profile, which correlates with the electrical transduction of the signal, thus allowing the detection of the nucleic acid structure. We also provide rules of thumb for the optimization of the design of the device and more generally for the integration of computationally driven design approaches.