We present the design, fabrication, and characterisation of an array of optical slot-waveguide ring resonator sensors, integrated with microfluidic sample handling in a compact cartridge, for multiplexed real-time label-free biosensing. Multiplexing not only enables high throughput, but also provides reference channels for drift compensation and control experiments. Our use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, our novel use of a dual surface-energy adhesive film to bond a hard plastic shell directly to the PDMS microfluidic network allows for fast and leak-tight assembly of compact cartridges with tightly spaced fluidic interconnects. The high sensitivity of the slot-waveguide resonators, combined with on-chip referencing and physical modelling, yields a volume refractive index detection limit of 5 x 10(-6) refractive index units (RIUs) and a surface mass density detection limit of 0.9 pg mm(-2), to our knowledge the best reported values for integrated planar ring resonators.

QC 20100715

Abstract-This article presents electrically-based sensors made of high quality silicon nanowire field effect transistors (SiNWFETs) for high sensitive detection of vascular endothelial growth factor (VEGF) molecules. SiNW-FET devices, fabricated through an IC/CMOS compatible top-down approach, are covalently functionalized with VEGF monoclonal antibodies in order to sense VEGF. Increasing concentrations of VEGF in the femto molar range determine increasing conductance values as proof of occurring immuno-reactions at the nanowire (NW) surface. These results confirm data in literature about the possibility of sensing pathogenic factors with SiNW-FET sensors, introducing the innovating aspect of detecting biomolecules in dry conditions.

Abstract-The sensitive analysis of proteins is central to disease diagnosis. The detection and investigation of angiogenic and inflammatory ligands in the tumor tissue can further improve the level of knowledge of the cancer disease by capturing the heterogeneity and the complexity of the tumor microenvironment. In previous works we demonstrated that high quality Silicon Nanowire Field Effect Transistors (SiNW-FETs) can be used to sense very low concentration (fM) of pathogenic factors in controlled Phosphate Buffered Saline (PBS). In this work, we show SiNW-FETs as biosensors for the detection of cancer markers in tumor extracts, as proof of our technology to successfully work on real patients' sample. In particular, we achieved the detection of exogenously added rabbit antigen in a much more complex environment, i.e. a human breast tumor extract. Our results show specific and high sensitive antigen detection with p-type SiNWFETs in the femto-molar range. Further and most importantly, the wires sense rabbit antigen molecules in the presence of a 100.000 mass excess of non-specific protein, indicating that the sensor is extremely resistant to noise.

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