Thesis assignments

Nanomechanical electronic nose for the detection of diseases in exhaled breath

Volatile organic compounds (VOCs) in breath are a marker for a range of diseases such as cancer, diabetes and tuberculosis. By sensing such VOCs using an electronic nose, COPD patients can be discriminated from lung cancer patients in 85 % of the cases correctly. Inorganic Materials Science group (IMS) has developed a nanomechanical electronic nose with excellent sensitivity and selectivity.

Recently, the responses of the electronic nose have shown to exhibit undesirable cross-sensitivity to several VOCs. We introduce coatings to improve the sensitivity of the electronic nose. Currently, develop the chemical functionalization using self-assembled monolayers (SAMs) to improve the capabilities of the sensor.

Figure 1 Nanomechanical electronic nose showing specific absorption of VOCs in exhaled breath on self-assembled monolayers integrated on the cantilevers

In this project we will investigate the absorption mechanisms of VOCs on self-assembled monolayers (SAM), deposited on the nanomechanical sensors. In particular we will study the Langmuir isotherms as a function of the pH and polarity of the SAMs. Furthermore, reversibility of the sensor will be monitored using temperature cycling. By studying the stiffness and mass binding on the sensor, these mechanisms can be studied individually, using the fact that the tip of the nanomechanical cantilever is expected to be more mass responsive while on towards the clamp it is more stiffness responsive. There is the opportunity to carry out part of the work at collaborator Philips Research, Eindhoven, where specialized equipment is available (GC/MS). The project will be directed as the insight progresses.

Ruud Steenwelle,