Nonlocal Timoshenko beam theory for vibration of carbon nanotube-based biosensor

This article studies vibration of carbon nanotube (CNT)-based biosensor. A CNT-based biosensor is modeled as a nonlocal Timoshenko beam made of multiwall CNT carrying a spherical nanoscale bio-object at the free end, and the influence of the rotary inertia of the bio-object itself is considered. The fundamental frequencies are computed via the transfer function method. The effects of the attached spherical bio-objectʹs rotary inertia and mass, the length-to-diameter of the CNT on the natural frequencies are discussed. If the nonlocal parameter is neglected, the frequencies for four possible cases are compared. Obtained results show that the rotary inertia decreases the fundamental frequency, while an increase in the diameter of the attached bio-object reduces the natural frequency, but causes frequency shift to rise. The mass sensitivity of biosensor can be improved for short CNTs used. The rotary inertia of the attached bio-object has a strong effect on the natural frequencies and cannot be simply neglected. The nonlocal Timoshenko beam model is more adequate than the nonlocal Euler-Bernoulli beam model for short CNT biosensors. Obtained results are helpful to the design of micro-cantilevered resonator as atomic-resolution mass sensor or biosensor.