Carbon-based nanomaterials, such as carbon nanotubes (CNTs) and graphene, have gained significant interest as one of the most promising materials in biological applications due to their unique physical and chemical properties. Recently we have developed an optoelectronic probing system, combining CNT/graphene transistors with scanning photocurrent measurements, fluorescence microscopy, and optical trapping techniques to investigate the molecular interface between CNTs/graphene and biological systems. Here, optical tweezers have been used to manipulate individual DNA molecules with sub-piconewton force precision and to directly measure the binding force between a DNA molecule and a CNT. Three-dimensional scanning photocurrent microscopy has been utilized to monitor the morphology changes of CNTs, allowing for a comprehensive reconstruction of the CNT-DNA interaction dynamics. We have also integrated graphene-based scanning photocurrent microscopy with microfluidic platforms to study the electrical activity in neuronal networks. These fundamental studies not only provide a new platform for exploring mechanical and electrical coupling at nanobio-interfaces, but also shed light on new design rules for future nanobioelectronics.