No abstract

We designed and fabricated gravimetric sensors composed of silicon (Si) microbeams surrounded by silicon nitride (SiN) anchors. The oscillation properties of the fabricated devices show that a single oscillation mode originating from quasi-one-dimensional microbeams appears at an applied alternating electric field, which motion is well matched to the theoretical predictions and is much different from the dimensionally mixed oscillation modes in normal non-anchored devices. In addition, in order to elucidate the possibilities of the devices for mass sensing applications, we measured the frequency shift as a function of mass loading in a self-assembled monolayer of 3-aminopropyltrimethoxysilane and Au nanoparticles. The resulting limit of detection was 1.05 × 10−18 g/Hz, which is an extremely high value for micro electromechanical system gravimetric sensors relative to the normal ones.

Gas-sensor array technology, which has been much utilized in the field of food technology by the name of 'electronic nose' is drawing attention in diagnosing lung cancer based on the analysis of the exhaled human breath. Much understanding has been accomplished about the composition of the volatile organic compounds (VOCs) of the human exhaled breath, in spite of some variations depending on research groups due mainly to lack of the standardization of the sensing procedures. Since VOCs may be produced during the process of cellular metabolism, difference in the cellular metabolism between healthy cells and lung cancer cells are expected to be reflected on the composition variation of the exhaled VOCs. Several studies have attempted to apply the gas-sensor array technology to lung cancer analysis using many different types of sensors including metal oxide, carbon black-polymer composite, surface acoustic wave, and gold nanoparticles. In this mini-review VOC as biomarkers, sensor array technology and application of the array technology for the diagnosis of cancer disease have been described.

No abstract