TY - JOUR
T1 - Lensless, reflection-based dark-field microscopy (RDFM) on a CMOS chip
AU - Imanbekova, Meruyert
AU - Perumal, Ayyappasamy Sudalaiyadum
AU - Kheireddine, Sara
AU - Nicolau, Dan V.
AU - Wachsmann-Hogiu, Sebastian
N1 - Funding Information:
Natural Sciences and Engineering Research Council of Canada (Discovery Grant RGPIN-2018-05675, 238925, Discovery); Bolashak (Scholarship).
Funding Information:
This work was financially supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), Discovery Grant RGPIN-2018-05675 (to S.W.-H.), Natural Sciences and Engineering Research Council (NSERC) Discovery Project No 238925 (to D.V.N.); M.I. acknowledges the Bolashak International Scholarship for PhD studies.
PY - 2020/9/1
Y1 - 2020/9/1
N2 - We present for the first time a lens-free, oblique illumination imaging platform for on-sensor dark- field microscopy and shadow-based 3D object measurements. It consists of an LED point source that illuminates a 5-megapixel, 1.4 µm pixel size, back-illuminated CMOS sensor at angles between 0° and 90°. Analytes (polystyrene beads, microorganisms, and cells) were placed and imaged directly onto the sensor. The spatial resolution of this imaging system is limited by the pixel size (∼1.4 µm) over the whole area of the sensor (3.6×2.73 mm). We demonstrated two imaging modalities: (i) shadow imaging for estimation of 3D object dimensions (on polystyrene beads and microorganisms) when the illumination angle is between 0° and 85°, and (ii) dark-field imaging, at >85° illumination angles. In dark-field mode, a 3-4 times drop in background intensity and contrast reversal similar to traditional dark-field imaging was observed, due to larger reflection intensities at those angles. With this modality, we were able to detect and analyze morphological features of bacteria and single-celled algae clusters.
AB - We present for the first time a lens-free, oblique illumination imaging platform for on-sensor dark- field microscopy and shadow-based 3D object measurements. It consists of an LED point source that illuminates a 5-megapixel, 1.4 µm pixel size, back-illuminated CMOS sensor at angles between 0° and 90°. Analytes (polystyrene beads, microorganisms, and cells) were placed and imaged directly onto the sensor. The spatial resolution of this imaging system is limited by the pixel size (∼1.4 µm) over the whole area of the sensor (3.6×2.73 mm). We demonstrated two imaging modalities: (i) shadow imaging for estimation of 3D object dimensions (on polystyrene beads and microorganisms) when the illumination angle is between 0° and 85°, and (ii) dark-field imaging, at >85° illumination angles. In dark-field mode, a 3-4 times drop in background intensity and contrast reversal similar to traditional dark-field imaging was observed, due to larger reflection intensities at those angles. With this modality, we were able to detect and analyze morphological features of bacteria and single-celled algae clusters.
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U2 - 10.1364/BOE.394615
DO - 10.1364/BOE.394615
M3 - Article
AN - SCOPUS:85096212549
VL - 11
SP - 4942
EP - 4959
JO - Biomedical Optics Express
JF - Biomedical Optics Express
SN - 2156-7085
IS - 9
ER -