A semiconductor electronic nose with a sensor array of 15 elements has been fabricated by magnetron radio frequency sputtering technique for detecting various volatile organic compounds (VOC5) in a low concentration range from 50 to 250 ppm in air at 300°C. The main components of the array have been titanium oxide and tin oxide (the latter has been doped with different Pt doses) semiconductor oxides with different thicknesses. A good single classification for six tested VOCs (propanal, methyl ethyl ketone, octane, benzene, toluene, and chloroform) has been obtained from this electronic nose through the technique of principal component analysis. In general, good response times, sensitivity, and reproducibility values have been obtained for all sensors, but it is interesting to underline the sensitivity increases to these gases from sensors in which titanium oxide is used for their preparation.

No abstract

The objective of this thesis is the development and characterization of optical label-free biosensors based on Bio-Photonic sensing Cells (BICELLs). BICELL is a novel biosensor concept developed by the research group, and it consists of a combination of vertical interrogation optical techniques and photonic structures produced by using micro-and nanofabrication methods.Several main conclusions are extracted from this work. Firstly, a standard BICELL is defined based on FP interferometers, which demonstrated its capacity for accomplishing performance comparisons among different structured BICELLs, as well as to achieve low-cost immunoassays.Different available fabrication techniques were studied for BICELL manufacturing. It is found that contact lithography at wafer scale produce cost-effective, reproducible and high quality structures. The resolution achieved was 700 nm.Study on the response of developed BICELLs to immunoassays is performed within this work.It is therefore studied the influence of BICELLs based on different geometries and sizes in the immunoassay, which resulted in a new approach to predict the biosensing behaviour of any structured optical biosensor relating to its effective surface and optical sensitivity. Also, it is demonstrated a novel and low-cost characterization technique of the experimental optical sensitivity, based on ultrathin-film deposition. Finally, it is also demonstrated the capability of using the developed BICELLs in this thesis for real applications detection of hormones, virus and proteins.

No abstract