Shadow masking for nanomaterial-based biosensors incorporated with a microfluidic device.

Integrating PDMS channels and chips containing pre-functionalized biosensors into microfluidic devices with irreversible sealing has been challenging because the integration process requires use of an O2 plasma treatment that usually destroys the biosensors. In this study, we examined the usefulness of introducing a shadow mask into the process as a method of protecting the pre-functionalized biosensors. Single nanowire sensors were pre-functionalized with fluorescently labeled biomolecules and then subjected to O2 plasma with and without the shadow mask.

Detection of cardiac biomarkers using single polyaniline nanowire-based conductometric biosensors.

The detection of myoglobin (Myo), cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), and b-type natriuretic peptide (BNP) plays a vital role in diagnosing cardiovascular diseases. Here we present single site-specific polyaniline (PANI) nanowire biosensors that can detect cardiac biomarkers such as Myo, cTnI, CK-MB, and BNP with ultra-high sensitivity and good specificity. Using single PANI nanowire-based biosensors integrated with microfluidic channels, very low concentrations of Myo (100 pg/mL), cTnI (250 fg/mL), CK-MB (150 fg/mL), and BNP (50 fg/mL) were detected.

Rapid real-time electrical detection of proteins using single conducting polymer nanowire-based microfluidic aptasensor.

Single polypyrrole (PPy) nanowire-based microfluidic aptasensors were fabricated using a one-step electrochemical deposition method. The successful incorporation of the aptamers into the PPy nanowire was confirmed by fluorescence microscopy image. The microfluidic aptasensor showed responses to IgE protein solutions in the range from 0.

Materialization of single multicomposite nanowire: entrapment of ZnO nanoparticles in polyaniline nanowire.

We present materialization of single multicomposite nanowire (SMNW)-entrapped ZnO nanoparticles (NPs) via an electrochemical growth method, which is a newly developed fabrication method to grow a single nanowire between a pair of pre-patterned electrodes. Entrapment of ZnO NPs was controlled via different conditions of SMNW fabrication such as an applied potential and mixture ratio of NPs and aniline solution. The controlled concentration of ZnO NP results in changes in the physical properties of the SMNWs, as shown in transmission electron microscopy images.

Ultrasensitive protein detection using an aptamer-functionalized single polyaniline nanowire.

A highly sensitive, conductometric and label-free biosensor for the detection of immunoglobulin E (IgE) is developed based on the immobilzation of the IgE aptamer onto a single polyaniline nanowire electrochemically synthesized in a facile and controllable way.

Thermionic field emission transport in carbon nanotube transistors.

With experimental and analytical analysis, we demonstrate a relationship between the metal contact work function and the electrical transport properties saturation current (Isat) and differential conductance (σsd=∂Isd/∂Vsd) in ambient exposed carbon nanotubes (CNT). A single chemical vapor deposition (CVD) grown 6 mm long semiconducting single-walled CNT is electrically contacted with a statistically significant number of Hf, Cr, Ti, Pd, and Au electrodes, respectively. The observed exponentially increasing relationship of Isat and σsd with metal contact work function is explained by a theoretical model derived from thermionic field emission.

Highly sensitive single polyaniline nanowire biosensor for the detection of immunoglobulin G and myoglobin.

A single polyaniline (PANI) nanowire-based biosensor was established to detect immunoglobulin G (IgG) and myoglobin (Myo), which is one of the cardiac biomarkers. The single PANI nanowires were fabricated via an electrochemical growth method, in which single nanowires were formed between a pair of patterned electrodes. The single PANI nanowires were functionalized with monoclonal antibodies (mAbs) of IgG or Myo via a surface immobilization method, using 1-ethyl-3-(3-dimethyaminopropyl) carbodiimide (EDC), and N-hydroxysuccinimde (NHS).

Anomalous Schottky barriers and contact band-to-band tunneling in carbon nanotube transistors.

Devices incorporating nanoscale materials, particularly carbon nanotubes (CNTs), offer exceptional electrical performance. Absent, however, is an experimentally backed model explaining contact-metal work function, device layout, and environment effects. To fill the void, this report introduces a surface-inversion channel model based on low temperature and electrical measurements of a distinct single-walled semiconducting CNT contacted by Hf, Cr, Ti, and Pd electrodes.