Fungal Spore Sensor Design Using Magnetic Resonance Force Microscopy

Abstract

This work explores some of the considerations for the design and operation of a fungal spore sensor using Magnetic Resonance Force Microscopy (MRFM). This work starts by introducing the physics, components and theory of operation which make MRFM a favourable method for detecting the presence of fungal spores, which have physical dimensions in the range of a few microns to a few hundred microns.

MATLAB was used to simulate changes in the dipole magnetic force which acts between a mold spore and a MEMS cantilever beam during a MRFM experiment. The dimensions, characteristics and response of the cantilever beam is estimated using MATLAB and re ned with multiple simulations in COMSOL Multiphysics. The results are two cantilever models, one made using silicon and the other silicon nitride, have approximate quality factors of 30, spring constants around 80 10^6 N/m and resonance frequencies close to 10 kHz.

This work also discusses the proposed manufacturing process and considerations for the MEMS cantilever structure and the additional components of the intended prototype sensor. A sequence of operation for the initial calibration and typical operation of the spore sensor is also included in this work. The fungal spore itself is adhered within the sensing range of the sensor by using an antibody selectively chosen to bind with the targeted spore. This work concentrates on the detection of the Botryris cinerea fungal spore, however the results from this work can be easily expanded on to detect additional fungal spores by changing the monoclonal antibody used to target the other spore types