Aptamer-Sensitized Nanoribbon Biosensor for Ovarian Cancer Marker Detection in Plasma

The detection of CA 125 protein in buffer solution with a silicon-on-insulator (SOI)-based nanoribbon (NR) biosensor was experimentally demonstrated. In the biosensor, sensor chips, bearing an array of 12 nanoribbons (NRs) with n-type conductance, were employed. In the course of the analysis with the NR biosensor, the target protein was biospecifically captured onto the surface of the NRs, which was sensitized with covalently immobilized aptamers against CA 125. Atomic force microscopy (AFM) and mass spectrometry (MS) were employed in order to confirm the formation of the probe–target complexes on the NR surface. Via AFM and MS, the formation of aptamer–antigen complexes on the surface of SOI substrates with covalently immobilized aptamers against CA 125 was revealed, thus confirming the efficient immobilization of the aptamers onto the SOI surface. The biosensor signal, resulting from the biospecific interaction between CA 125 and the NR-immobilized aptamer probes, was shown to increase with an increase in the target protein concentration. The minimum detectable CA 125 concentration was as low as 1.5 × 10−17 M. Moreover, with the biosensor proposed herein, the detection of CA 125 in the plasma of ovarian cancer patients was demonstrated.

Формирование и исследование оптических свойств локально растянутых Ge микроструктур, встроенных в резонаторы

In this work, formation of locally tensile strained Ge structures (micro-bridges) on SOI substrates embedded into microcavities is reported and their optical properties are discussed. The cavity compatible with the shape of the active region was designed in such a way as to provide an effective localization of the electromagnetic field in the active region of the structure, as well as to minimize the strain redistribution due to the cavity formation. Micro-photoluminescence (PL) studies have shown a remarkable enhancement of the PL intensity for the locally strained areas as compared to the initial Ge film. It was shown that the formation of a microcavity leads to a decrease in the maximum strain in the active region of the structure, but provides an overall increase in the PL intensity.