Wide-field lensless fluorescent imaging on a chip
An imaging device uses a fiber optic faceplate (FOF) with a compressive sampling algorithm for the fluorescent imaging of a sample over an large field-of-view without the need for any lenses or mechanical scanning. The imaging device includes a sample holder configured to hold a sample and a prism or hemispherical glass surface disposed adjacent the sample holder on a side opposite the lower surface of the sample holder. A light source is configured to illuminate the sample via the prism or the hemispherical surface, wherein substantially all of the light is subject to total internal reflection at the lower surface of the sample holder. The FOF is disposed adjacent to the lower surface of the sample holder, the fiber optic array having an input side and an output side. The device includes an imaging sensor array disposed adjacent to the output side of the fiber optic array.
1. An imaging device comprising:
a sample holder configured to hold a sample, the sample holder having a lower surface and comprising a plurality of micro-channels located at different vertical positions;
a hemispheric surface disposed adjacent the sample holder on a side opposite the lower surface of the sample holder;
a light source configured to illuminate the sample via the hemispheric surface, wherein substantially all of the light is subject to total internal reflection at the lower surface of the sample holder;
a fiber optic array disposed adjacent to the lower surface of the sample holder, the fiber optic array having an input side and an output side, wherein the input side of the fiber optic array has higher density of fiber optic waveguides compared to density of fiber optic waveguides at the output side;
an imaging sensor array disposed adjacent to the output side of the fiber optic array, the imaging sensor array outputting image frames of the sample; and
a processor configured to compressively decode the image frames from the imaging sensor array and output decoded image frames having a higher resolution.
2. The imaging device of claim 1 , further comprising an absorption filter interposed between the output side of the fiber optic array and the imaging sensor array.
3. The imaging device of claim 1 wherein the density of fiber optic waveguides at the input side of the fiber optic array is more than five times greater than the density of the fiber optic waveguides at the output side of the fiber optic array.
4. The imaging device of claim 1 , wherein the fiber optic array has a thickness within the range of about 100 μm to about 5 cm.
5. A method of imaging a sample comprising:
illuminating the sample contained in a sample holder comprising a plurality of micro-channels located at different vertical positions with fluorescent excitation radiation passing through a hemispheric surface prior to illuminating the sample, wherein substantially all of the fluorescent excitation radiation is subject to total internal reflection at a lower surface of the sample holder and fluorescent emission radiation from the sample exits the sample holder;
transferring the fluorescent emission radiation exiting the sample holder to an imaging sensor array via a fiber optic array interposed between the lower surface of the sample holder and a surface of the imaging sensor array, and wherein an input side of the fiber optic array has higher density of fiber optic waveguides compared to the density of fiber optic waveguides at an output side;
acquiring image frames of the fluorescent emission radiation exiting the output side of the fiber optic array with the imaging sensor array; and
subjecting the acquired image frames to compressive decoding to produce decoded image frames having a higher resolution.
6. The method of claim 5 , wherein the sample comprises a plurality of cells.
7. The method of claim 5 , further comprising identifying one or more target cells contained within the plurality of cells.
8. The method of claim 5 , wherein a first air gap separates the lower surface of the sample holder from the input side of the fiber optic array and a second air gap separates the output side of the fiber optic array and the surface of the imaging sensor array.
9. The method of claim 8 , wherein the first and second air gaps between the fiber optic array and the sample holder and imaging sensor are within the range of about 1 to about 500 μm.