Fluorescence in situ hybridization (FISH) allows visualization of specific nucleic acid sequences within an intact cell or a tissue section. It is based on molecular recognition between a fluorescently labeled probe that penetrates the cell membrane of a fixed but intact sample and hybridizes to a nucleic acid sequence of interest within the cell, rendering a measurable signal. FISH has been applied to, for example, gene mapping, diagnosis of chromosomal aberrations and identification of pathogens in complex samples as well as detailed studies of cellular structure and function. However, FISH protocols are complex, they comprise of many fixation, incubation and washing steps involving a range of solvents and temperatures and are, thus, generally time consuming and labor intensive. The complexity of the process, the relatively high-priced fluorescent probes and the fairly high-end microscopy needed for readout render the whole process costly and have limited wider uptake of this powerful technique. In recent years, there have been attempts to transfer FISH assay protocols onto microfluidic lab-on-a-chip platforms, which reduces the required amount of sample and reagents, shortens incubation times and, thus, time to complete the protocol, and finally has the potential for automating the process. Here, we review the wide variety of approaches for lab-on-chip-based FISH that have been demonstrated at proof-of-concept stage, ranging from FISH analysis of immobilized cell layers, and cells trapped in arrays, to FISH on tissue slices. Some researchers have aimed to develop simple devices that interface with existing equipment and workflows, whilst others have aimed to integrate the entire FISH protocol into a fully autonomous FISH on-chip system. Whilst the technical possibilities for FISH on-chip are clearly demonstrated, only a small number of approaches have so far been converted into off-the-shelf products for wider use beyond the research laboratory.

中文翻译：

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FISH 和芯片：FISH 分析微流体平台综述。


荧光原位杂交 (FISH) 可实现完整细胞或组织切片内特定核酸序列的可视化。它基于荧光标记探针之间的分子识别，该探针穿透固定但完整样品的细胞膜并与细胞内感兴趣的核酸序列杂交，从而产生可测量的信号。 FISH 已应用于基因作图、染色体畸变诊断、复杂样品中病原体的鉴定以及细胞结构和功能的详细研究等领域。然而，FISH 方案很复杂，包括许多固定、孵育和洗涤步骤，涉及一系列溶剂和温度，因此通常耗时且费力。该过程的复杂性、相对较高价格的荧光探针以及读出所需的相当高端的显微镜使得整个过程成本高昂，并限制了这种强大技术的更广泛采用。近年来，人们尝试将 FISH 检测方案转移到微流控芯片实验室平台上，这减少了所需的样品和试剂量，缩短了孵育时间，从而缩短了完成方案的时间，最终实现了该过程自动化的潜力。在这里，我们回顾了在概念验证阶段已经证明的基于芯片实验室的 FISH 的各种方法，从固定细胞层和阵列中捕获的细胞的 FISH 分析到组织切片上的 FISH 。一些研究人员的目标是开发与现有设备和工作流程接口的简单设备，而其他研究人员的目标是将整个 FISH 协议集成到完全自主的 FISH 片上系统中。 虽然片上 FISH 的技术可能性已得到明确证明，但迄今为止，只有少数方法被转化为现成产品，以供研究实验室以外的更广泛用途。