Rapid, label-free, electrical whole blood bioassay based on nanobiosensor systems.

Biomarker detection based on nanowire biosensors has attracted a significant amount of research effort in recent years. However, only very limited research work has been directed toward biomarker detection directly from physiological fluids mainly because of challenges caused by the complexity of media. This limitation significantly reduces the practical impact generated by the aforementioned nanobiosensors.

Importance of controlling nanotube density for highly sensitive and reliable biosensors functional in physiological conditions.

Biosensors utilizing carbon nanotube field-effect transistors have a tremendous potential to serve as the basis for the next generation of diagnostic systems. While nanotubes have been employed in the fabrication of multiple sensors, little attention has previously been paid to how the nanotube density affects the biosensor performance. We conducted a systematic study of the effect of density on the performance of nanotube biosensors and discovered that this parameter is crucial to achieving consistently high performance.

A calibration method for nanowire biosensors to suppress device-to-device variation.

Nanowire/nanotube biosensors have stimulated significant interest; however, the inevitable device-to-device variation in the biosensor performance remains a great challenge. We have developed an analytical method to calibrate nanowire biosensor responses that can suppress the device-to-device variation in sensing response significantly. The method is based on our discovery of a strong correlation between the biosensor gate dependence (dI(ds)/dV(g)) and the absolute response (absolute change in current, DeltaI).

A nanoelectronic enzyme-linked immunosorbent assay for detection of proteins in physiological solutions.

Semiconducting nanowires are promising ultrasensitive, label-free sensors for small molecules, DNA, proteins, and cellular function. Nanowire field-effect transistors (FETs) function by sensing the charge of a bound molecule. However, solutions of physiological ionic strength compromise the detection of specific binding events due to ionic (Debye) screening.

Label-free, electrical detection of the SARS virus N-protein with nanowire biosensors utilizing antibody mimics as capture probes.

Antibody mimic proteins (AMPs) are polypeptides that bind to their target analytes with high affinity and specificity, just like conventional antibodies, but are much smaller in size (2-5 nm, less than 10 kDa). In this report, we describe the first application of AMP in the field of nanobiosensors. In(2)O(3) nanowire based biosensors have been configured with an AMP (Fibronectin, Fn) to detect nucleocapsid (N) protein, a biomarker for severe acute respiratory syndrome (SARS).

A nanoelectronic nose: a hybrid nanowire/carbon nanotube sensor array with integrated micromachined hotplates for sensitive gas discrimination.

A novel hybrid chemical sensor array composed of individual In(2)O(3) nanowires, SnO(2) nanowires, ZnO nanowires, and single-walled carbon nanotubes with integrated micromachined hotplates for sensitive gas discrimination was demonstrated. Key features of our approach include the integration of nanowire and carbon nanotube sensors, precise control of the sensor temperature using the micromachined hotplates, and the use of principal component analysis for pattern recognition. This sensor array was exposed to important industrial gases such as hydrogen, ethanol and nitrogen dioxide at different concentrations and sensing temperatures, and an excellent selectivity was obtained to build up an interesting 'smell-print' library of these gases.

Rapid and label-free cell detection by metal-cluster-decorated carbon nanotube biosensors.

In this paper, the use of carbon nanotube biosensors toward alga cell detection was examined. The biosensor devices were fabricated on complete 4 in. wafers by first growing carbon nanotubes (CNTs) and then depositing metal electrodes using a shadow mask.

Transparent electronics based on transfer printed aligned carbon nanotubes on rigid and flexible substrates.

We report high-performance fully transparent thin-film transistors (TTFTs) on both rigid and flexible substrates with transfer printed aligned nanotubes as the active channel and indium-tin oxide as the source, drain, and gate electrodes. Such transistors have been fabricated through low-temperature processing, which allowed device fabrication even on flexible substrates. Transparent transistors with high effective mobilities (approximately 1300 cm(2) V(-1) s(-1)) were first demonstrated on glass substrates via engineering of the source and drain contacts, and high on/off ratio (3 x 10(4)) was achieved using electrical breakdown.