This paper proposes and investigates a label-free dielectrically modulated biosensor employing a Gate All Around Tree-Shaped Nanosheet Field Effect Transistor (GAA-TS-NSFET). Excellent sensitivity to the biomolecules which are charged and neutral are demonstrated by the electrical properties of the suggested biosensor when evaluated under various biomolecule influences. A thorough sensitivity assessment is used to assess the sensing capabilities of the biosensors with various channel configurations. As indicators of biosensor sensitivity variation, we examine the subthreshold swing (SS), threshold voltage (Vth), and current switching ratio (Ion/Ioff). According to the findings, an additional channel acts as an interbridge, allowing the tree-shaped biosensor to attain the best sensitivity compared to biosensors based on NSFETs. Additionally, the article investigates how various spacer materials impact sensitivity. We also run several scenarios to see how different fill percentages affect the proposed biosensor’s sensitivity. The amount of biomolecules present determines its sensitivity. Finally, the suggested biosensor’s sensitivity is compared to other notable biosensing application efforts in a status map. The proposed GAA-TS-NSFET-based biosensor outperforms the previous works concerning Ion/Ioff sensitivity.