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Study Data from Delft University of Technology Provide New Insights into Silicon (Cavity-enhanced optical trapping of bacteria using a silicon...

July 1, 2014

Study Data from Delft University of Technology Provide New Insights into Silicon (Cavity-enhanced optical trapping of bacteria using a silicon photonic crystal)

By a News Reporter-Staff News Editor at Life Science Weekly -- Investigators publish new report on Silicon. According to news reporting from Delft, Netherlands, by NewsRx journalists, research stated, "On-chip optical trapping and manipulation of cells based on the evanescent field of photonic structures is emerging as a promising technique, both in research and for applications in broader context. Relying on mass fabrication techniques, the involved integration of photonics and microfluidics allows control of both the flow of light and water on the scale of interest in single cell microbiology."

The news correspondents obtained a quote from the research from the Delft University of Technology, "In this paper, we demonstrate for the first time optical trapping of single bacteria (B. subtilis and E. coli) using photonic crystal cavities for local enhancement of the evanescent field, as opposed to the synthetic particles used so far. Three types of cavities (H0, H1 and L3) are studied, embedded in a planar photonic crystal and optimized for coupling to two collinear photonic crystal waveguides. The photonic crystals are fabricated on a silicon-on-insulator chip, onto which a fluidic channel is created as well. For each of the cavities, when pumped at the resonance wavelength (around 1550 nm), we clearly demonstrate optical trapping of bacteria, in spite of their low index contrast w.r.t. water. By tracking the confined Brownian motion of B. subtilis spores in the traps using recorded microscope observations, we derive strong in-plane trap stiffnesses of about 7.6 pN nm(-1) W(-1). The values found agree very well with calculations based on the Maxwell stress tensor for the force and finite-difference time-domain simulations of the fields for the fabricated cavity geometries."

According to the news reporters, the research concluded: "We envision that our lab-on-a-chip with photonic crystal traps opens up new application directions, e.g. immobilization of single bio-objects such as mammalian cells and bacteria under controlled conditions for optical microscopy studies."

For more information on this research see: Cavity-enhanced optical trapping of bacteria using a silicon photonic crystal. Lab On a Chip - Miniaturisation for Chemistry and Biology, 2013;13(22):4358-65 (see also Silicon).

Our news journalists report that additional information may be obtained by contacting T. van Leest, Kavli Institute of Nanoscience Delft and Dept. of Imaging Science and Technology, Delft University of Technology, Lorentzweg 1, 2628 CJ, Delft, Netherlands.

Keywords for this news article include: Delft, Europe, Silicon, Netherlands.

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Source: Life Science Weekly

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