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Liu P.Y.,University Paris Est Creteil | Liu P.Y.,Nanyang Technological University | Chin L.K.,Nanyang Technological University | Ser W.,Nanyang Technological University | And 11 more authors.
Lab on a Chip - Miniaturisation for Chemistry and Biology | Year: 2016

Cell refractive index is a key biophysical parameter, which has been extensively studied. It is correlated with other cell biophysical properties including mechanical, electrical and optical properties, and not only represents the intracellular mass and concentration of a cell, but also provides important insight for various biological models. Measurement techniques developed earlier only measure the effective refractive index of a cell or a cell suspension, providing only limited information on cell refractive index and hence hindering its in-depth analysis and correlation. Recently, the emergence of microfluidic, photonic and imaging technologies has enabled the manipulation of a single cell and the 3D refractive index of a single cell down to sub-micron resolution, providing powerful tools to study cells based on refractive index. In this review, we provide an overview of cell refractive index models and measurement techniques including microfluidic chip-based techniques for the last 50 years, present the applications and significance of cell refractive index in cell biology, hematology, and pathology, and discuss future research trends in the field, including 3D imaging methods, integration with microfluidics and potential applications in new and breakthrough research areas. © 2016 The Royal Society of Chemistry. Source


Chin L.K.,Nanyang Technological University | Ayi T.C.,Defence Medical and Environmental Institute | Yap P.H.,Defence Medical and Environmental Institute | Liu A.Q.,Nanyang Technological University
14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010 | Year: 2010

This paper reports a continuous cell culture chip that employs droplet microfluidics to encapsulate suspension cells in a droplet and the cell droplet is passively stored in a storage chamber during the long-period cell culture process. The proposed system provides a closed micro-environment for cell culture which has advantages of cell droplet isolation to avoid cross contamination, simple droplet manipulation for fusion-division cycles and easy integration for further cell-based analytical techniques. In the demonstrated experiment, myeloma cells are successfully cultured using the developed integrated droplet cell culture system. Source


Chin L.K.,Nanyang Technological University | Ayi T.C.,Defence Medical and Environmental Institute | Yap P.H.,Defence Medical and Environmental Institute | Liu A.Q.,Nanyang Technological University
2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11 | Year: 2011

This paper presents an on-chip immersion refractometer for the measurement of size, shape and refractive index of protozoa in treated water. The key features of the on-chip immersion refractometer include (1) multiple single cyst trapping sites, which enable the measurement of multiple sample per test; and (2) zig-zag micromixer, which enables the refractive index variation of external medium as the key component of immersion refractometry. The results show that C. parvum oocysts have size of 3 to 7 m, spherical with ovality lower than 0.3, and refractive index of 1.418. G. lamblia cysts have size of 8 to 12 μm, oval with ovality higher than 0.3, and refractive index of 1.433. The refractive indices of the samples are measured with high precision of < 103. © 2011 IEEE. Source


Chin L.K.,Nanyang Technological University | Ayi T.C.,Defence Medical and Environmental Institute | Yap P.H.,Defence Medical and Environmental Institute | Liu A.Q.,Nanyang Technological University
15th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2011, MicroTAS 2011 | Year: 2011

This paper presents an on-chip null-method immersion refractometer for the measurement of size, shape and refractive index of protozoa in treated water. The key features of the on-chip immersion refractometer include (1) multiple single cyst trapping sites, which enable the measurement of multiple sample per test; and (2) zig-zag micromixer, which enables the refractive index variation of external medium as the key component of immersion refractometry. The results show that Cryptosporidium parvum oocysts have size of 3 to 7 μm, spherical with ovality lower than 0.3, and refractive index of 1.418. Giardia lamblia cysts have size of 8 to 12 μm, oval with ovality higher than 0.3, and refractive index of 1.433. The refractive i ndices of the samples are measured with high precision of < 10-3. Copyright © (2011) by the Chemical and Biological Microsystems Society. Source


Liu P.Y.,University of Marne-la-Vallee | Liu P.Y.,Nanyang Technological University | Chin L.K.,Nanyang Technological University | Ser W.,Nanyang Technological University | And 4 more authors.
CLEO: QELS - Fundamental Science, CLEO_QELS 2015 | Year: 2015

This paper presents an optofluidic imaging system to detect influenza virus infection via the change of refractive index based on scattering signature. This method allows for a direct monitor of the influenza flu virus. 2015 © OSA 2015. Source

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