In this paper, for the first time, an on-chip optofluidic imaging system is innovated to measure the biophysical signatures of single waterborne bacteria, including both their refractive indices and morphologies (size and shape), based on immersion refractometry. The key features of the proposed optofluidic imaging platform include (1) multiple sites for single-bacterium trapping, which enable parallel measurements to achieve higher throughput, and (2) a chaotic micromixer, which enables efficient refractive index variation of the surrounding medium. In the experiments, the distinctive refractive index of Echerichia coli, Shigella flexneri and Vibrio cholera are measured with a high precision of 5 × 10(-3) RIU. The developed optofluidic imaging system has high potential not only for building up a database of biophysical signatures of waterborne bacteria, but also for developing single-bacterium detection in treated water that is in real-time, label-free and low cost.
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http://dx.doi.org/10.1039/c4lc00783b | DOI Listing |
Nanophotonics
February 2024
Brave Analytics GmbH, Graz, Austria.
In many experiments, nanoparticles are located inside a microfluidic channel, and the light scattered by the particles becomes diffracted through the walls of the capillary. We here derive a simple but accurate approach for simulating the imaging of light through a cylindrical capillary under the assumption that the dimensions of the capillary are much larger than the wavelength of light. A comparison of the simulated images with experimental results shows very good agreement.
View Article and Find Full Text PDFNanophotonics
July 2024
The Department of Fiber Photonics, Leibniz Institute of Photonic Technology, Albert-Einstein-Street 9, 07745 Jena, Germany.
Here, we present the concept of flat-field capillary-assisted nanoparticle tracking analysis for the characterization of fast diffusing nano-objects. By combining diffusion confinement and spatially invariant illumination, i.e.
View Article and Find Full Text PDFHum Reprod
January 2025
Education Program in Reproduction and Development, EPRD, Department of obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia.
J Cell Sci
October 2024
Biomedical Imaging Group and Center for Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Adv Sci (Weinh)
September 2024
Bionanophotonic Systems Laboratory, Institute of Bioengineering, School of Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, 1015, Switzerland.
Organoid tumor models have emerged as a powerful tool in the fields of biology and medicine as such 3D structures grown from tumor cells recapitulate better tumor characteristics, making these tumoroids unique for personalized cancer research. Assessment of their functional behavior, particularly protein secretion, is of significant importance to provide comprehensive insights. Here, a label-free spectroscopic imaging platform is presented with advanced integrated optofluidic nanoplasmonic biosensor that enables real-time secretion analysis from single tumoroids.
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