Field-effect transistor (FET)-based biosensors allow label-free detection of biomolecules by measuring their intrinsic charges. We previously reported the extremely low limit of detection (LoD) on electrical field effect-based sensors using crumpled graphene (Nat. Comm. 2020). Here, we use FETs with a deformed monolayer graphene channel for the detection of various biomarkers. Neurotransmitter dopamine, sepsis-related IL-6 protein and two SARS-CoV-2 related proteins are successfully detected with the lowest LoDs ever reported, down to 1 attogram sensitivities. Moreover, we probed the dependence of sensitivity on the degree of crumpling, showing that higher degrees of crumpling lead to higher sensitivity. These results show, that this diagnostic technique is uniquely enhanced by the nanoscale morphology of the crumpled graphene FETs. The next steps are to develop a portable detection cell and demonstrate detection in viral transport media and clinical samples. In the future, this platform can be highly multiplexed and can target many multiple biomarkers on a chip and have a significant impact on the diagnostics market.