Performance Limits of Nanobiosensors



This time is dictated by the diffusion of molecules (e.g. cancer markers) through the solution and their subsequent capture at the sensor surface. Researchers at Purdue University show that this response is governed by the geometry of diffusion of the system and that nanobiosensors are capable of detecting bio-molecules at much lower concentration (up to 4-5 orders of magnitude) than the classical planar sensors (ISFETs or CHEMFETs).

Based on electrostatics considerations, it is well known that nanowires are more sensitive to adsorbed charges e.g., DNA or protein, compared to ISFET or CHEMFET sensors. This classical view of nanosensor response, however, misses the kinetic part of the detection process, i.e., when a sensor is inserted in a solution of target biomolecules, the time to capture a certain number of biomolecules also depends on the dimensions of the sensor.

Therefore, nanowire or nanosphere sensors, despite their superior electrostatic performance, will have to be designed carefully to achieve real time detection of target species at low concentrations.

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Performance Limits of Nanobiosensors