The analysis of individual biological nanoparticles has significantly advanced our understanding of fundamental biological processes but is also rapidly becoming relevant for molecular diagnostic applications in the emerging field of personalized medicine. Both optical and electrical methods for the detection and analysis of single biomolecules have been… (More)
Scanning impedance imaging (SH) uses a noncontacting electrical probe held at a known voltage and scanned over a thin sample on a ground plane in a conductive medium to obtain images of current. The current image is related in a nonlinear way to the conductivity of the sample. This paper develops the theory behind SII showing how the measured current… (More)
The massive outbreak of highly lethal Ebola hemorrhagic fever in West Africa illustrates the urgent need for diagnostic instruments that can identify and quantify infections rapidly, accurately, and with low complexity. Here, we report on-chip sample preparation, amplification-free detection and quantification of Ebola virus on clinical samples using hybrid… (More)
Optofluidic platforms used for biomolecular detection require spectral filtering for distinguishing analyte signals from unwanted background. Towards a fully integrated platform, an on-chip filter is required. Selective deposition of dielectric thin films on an optofluidic sensor based on antiresonant reflecting optical waveguide (ARROW) technology provides… (More)
Lambda DNA (λ-DNA) molecules were labeled with SYBR Gold nucleic acid stain using a PDMS-based programmable microfluidic chip (Automaton). Single DNA molecules were detected in a vertically integrated liquid-core waveguide chip.
Using an optofluidic chip with an integrated nanopore, a mixture of nanobeads and influenza viruses were opto-electrically detected. Different types of nanoparticles can be distinguished by different fluorescence wavelengths and fluorescence correlation functions.
Clinical Ebola RNAs are detected with virus concentration down to 6.25 × 10<sup>4</sup> pfu/ml on an optofluidic chip. Longer complementary pull-down DNA sequences provide better isolation and higher signals.
Microcantilevers have been investigated as high sensitivity, label free biosensors for approximately 15 years. In nearly all cases, a thin gold film deposited on the microcantilevers is used as an intermediate attachment layer because of the convenience of thiol-gold chemistry. Unfortunately, this attachment chemistry can be unstable when used with complex… (More)
A new type of hollow core waveguide fabricated with Ta<inf>2</inf>O<inf>5</inf> and SiO<inf>2</inf> films is demonstrated. The photoluminescence background of ARROW waveguides is decreased significantly by replacing Si<inf>3</inf>N<inf>4</inf> with Ta<inf>2</inf>O<inf>5</inf> films, while maintaining low optical losses.