Coskun Ahmet F, Su Ting-Wei, Sencan Ikbal, Ozcan Aydogan
Department of Electrical Engineering, University of California-Los Angeles, CA, USA.
J Vis Exp. 2011 Aug 17(54):3181. doi: 10.3791/3181.
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.
一般来说，片上无透镜成像旨在用更简单、更紧凑的设计取代基于透镜的大型光学显微镜，特别是用于高通量筛选应用。这个新兴的技术平台有潜力借助新颖的理论和数字重建算法，消除对大型和/或昂贵光学元件的需求。同样地，在此我们展示了一种片上荧光显微镜模式，它可以在大于0.6 - 8平方厘米的超宽视野（FOV）上实现例如小于4微米的空间分辨率，而无需使用任何透镜、机械扫描或基于薄膜的干涉滤光片。在这项技术中，荧光激发是通过由非相干光源照射的棱镜或半球形玻璃界面实现的。在与整个物体体积相互作用后，这种激发光通过在样品微流控芯片底部发生的全内反射（TIR）过程被反射掉。然后，来自被激发物体的荧光发射由光纤面板或锥形光纤收集，并被传送到光电传感器阵列，如电荷耦合器件（CCD）。通过使用基于压缩采样的解码算法，可以快速处理采集到的样品无透镜原始荧光图像，从而在大于0.6 - 8平方厘米的视野上产生例如小于4微米的分辨率。此外，使用相同的片上无透镜显微镜平台，还可以成功对例如间隔50 - 100微米的垂直堆叠微通道进行成像，这进一步提高了这种模式的整体通量。这个紧凑的片上荧光成像平台，背后有一个快速压缩解码器，对于高通量细胞计数、稀有细胞研究和微阵列分析可能非常有价值。
