We report the first use of differential terahertz time-domain spectroscopy for bioaffinity sensing. Binding is observed by measuring the transmission of a thin layer of biotin bound to the sensor protein avidin. We demonstrate the THz wave transmission of a sub-micron-thick film and sensitivity to 0.1 microg cm(-2) of biotin. These results point the way for a host of biosensor applications usin...

Lipid rafts are submicron proteolipid domains thought to be responsible for membrane trafficking and signaling. Their small size and transient nature put an understanding of their dynamics beyond the reach of existing techniques, leading to much contention as to their exact role. Here, we exploit the differences in light scattering from lipid bilayer phases to achieve dynamic imaging of nanosco...

Label-free Biodetection with Individual Plasmonic Nanoparticles by Gregory J. Nusz Department of Biomedical Engineering Duke University Date:_______________________ Approved: ___________________________ Ashutosh Chilkoti, Supervisor ___________________________ Adam P. Wax ___________________________ David J. Brady ___________________________ Anne Lazarides ___________________________ William Re...

Peripheral neuropathy is a common neurological problem that affects millions of people worldwide. Diagnosis and treatment of this condition are often hindered by the difficulties in making objective, noninvasive measurements of nerve fibers. Photoacoustic microscopy (PAM) has the ability to obtain high resolution, specific images of peripheral nerves without exogenous contrast. We demonstrated ...

Microand nanoscale chemical and structural heterogeneities, whether they are intrinsic material properties like grain boundaries or intentionally encoded via nanoscale fabrication techniques, pose a challenge to current material characterization methods. To precisely interrogate the electronic structure of these complex materials systems, spectroscopic techniques with high spatial resolution ar...

The increasing scale and complexity of quantitative proteomics studies complicate subsequent analysis of the acquired data. Untargeted label-free quantification, based either on feature intensities or on spectral counting, is a method that scales particularly well with respect to the number of samples. It is thus an excellent alternative to labeling techniques. In order to profit from this scal...

The diameters of blood vessels, especially in the brain, change dynamically over time to provide sufficient blood supply as needed. No existing technique allows noninvasive control of vascular diameter in vivo. We report that label-free irradiation with a femtosecond pulsed laser can trigger blood vessel contraction in vivo. In response to laser irradiation, cultured vascular smooth muscle cell...

Biosensors are one of the fundamental detection platforms in biotechnology. They take advantage of unique biomolecular interactions to capture and detect specific analytes on a surface. The detection versatility of biosensors has always been their key advantage and it has been demonstrated that they can detect almost any analyte such as DNA, proteins, metabolites, and even micro-organisms. Howe...

Utilizing its integrated camera as a spectrometer, we demonstrate the use of a smartphone as the detection instrument for a label-free photonic crystal biosensor. A custom-designed cradle holds the smartphone in fixed alignment with optical components, allowing for accurate and repeatable measurements of shifts in the resonant wavelength of the sensor. Externally provided broadband light incide...