title: Lensless fluorescent microscopy on a chip.
abstract: On-chip lensless imaging in general aims to replace bulky lens-based optical microscopes with simpler and more compact designs, especially for high-throughput screening applications. This emerging technology platform has the potential to eliminate the need for bulky and/or costly optical components through the help of novel theories and digital reconstruction algorithms. Along the same lines, here we demonstrate an on-chip fluorescent microscopy modality that can achieve e.g., <4 μm spatial resolution over an ultra-wide field-of-view (FOV) of >0.6-8 cm(2) without the use of any lenses, mechanical-scanning or thin-film based interference filters. In this technique, fluorescent excitation is achieved through a prism or hemispherical-glass interface illuminated by an incoherent source. After interacting with the entire object volume, this excitation light is rejected by total-internal-reflection (TIR) process that is occurring at the bottom of the sample micro-fluidic chip. The fluorescent emission from the excited objects is then collected by a fiber-optic faceplate or a taper and is delivered to an optoelectronic sensor array such as a charge-coupled-device (CCD). By using a compressive-sampling based decoding algorithm, the acquired lensfree raw fluorescent images of the sample can be rapidly processed to yield e.g., <4 μm resolution over an FOV of >0.6-8 cm(2). Moreover, vertically stacked micro-channels that are separated by e.g., 50-100 μm can also be successfully imaged using the same lensfree on-chip microscopy platform, which further increases the overall throughput of this modality. This compact on-chip fluorescent imaging platform, with a rapid compressive decoder behind it, could be rather valuable for high-throughput cytometry, rare-cell research and microarray-analysis.
authors.affiliation: Department of Electrical Engineering, University of California-Los Angeles, CA, USA.
authors.forename: Ahmet F
authors.initials: AF
authors.lastname: Coskun
authors.forename: Ting-Wei
authors.initials: TW
authors.lastname: Su
authors.forename: Ikbal
authors.initials: I
authors.lastname: Sencan
authors.forename: Aydogan
authors.initials: A
authors.lastname: Ozcan
mesh_terms: D000465:Algorithms; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000295:instrumentation* / Q000379:methods*