The microfluidics separation has absorbed wide-ranging attention in recent years due to its outstanding advantages in biological, medical, clinical, and diagnostical cell studies. While conventional separation methods failed to render the acceptable performance, microfluidics sorting methods offer many privileges such as high throughput, user-friendliness, minimizing sample volumes, cost-efficiency, non-invasive procedures, high precision, improved portability, quick processing, etc. Among the inertial microfluidics approaches such as the straight and curved microchannels, although the spiral microchannels, which are the sorts of passive separations, are complicated in concepts and geometries, they have demonstrated auspicious benefits for this purpose. Thus, numerous studies have strived to explain the principle of particle migrating and forces in these complex microchannels. However, a comprehensive understanding is still necessary. On the other side, it is manifest that the diagnosis and separation of circulating tumor cells (CTCs) from the blood are significant for targeted treatments of this detrimental disease. Therefore, this study aims to review the previous investigations and developments for understanding the CTC separation using the spiral microchannels straightforwardly and profoundly. After elucidating the inertial microfluidics and their governing physics in simple terms, we provide insights about spiral microchannels’ mechanism and concepts, the secondary flow, the cross-section effects on the separation processes, the investigation about CTCs in the spiral microchannels specifically, and finally, the future applications and challenges of this kind of inertial microfluidics. The analyses reveal that new approaches should be conducted to use spiral microchannels with combined cross-sections. These kinds of microchannels with optimum size and shape of cross-sections can improve performance efficiently.

近年来，微流体分离因其在生物、医学、临床和诊断细胞研究中的突出优势而受到广泛关注。虽然传统的分离方法未能提供可接受的性能，但微流体分选方法提供了许多优势，例如高通量、用户友好性、最小化样本量、成本效益、非侵入性程序、高精度、改进的便携性、快速处理等。在直线和弯曲微通道等惯性微流体方法中，虽然螺旋微通道是一种被动分离，但在概念和几何形状上都很复杂，但它们已经证明了这一目的的吉祥好处。因此，许多研究都在努力解释这些复杂微通道中粒子迁移和力的原理。但是，仍然需要全面的了解。另一方面，循环肿瘤细胞 (CTC) 的诊断和从血液中的分离对于这种有害疾病的靶向治疗很重要。因此，本研究旨在回顾以前的研究和发展，以直接而深刻地理解使用螺旋微通道的 CTC 分离。在简单地阐明惯性微流体及其控制物理之后，我们提供了关于螺旋微通道的机制和概念、二次流动、对分离过程的横截面影响、特别是对螺旋微通道中 CTC 的研究的见解，最后，这种惯性微流体的未来应用和挑战。分析表明，应该采用新方法来使用具有组合横截面的螺旋微通道。这些具有最佳尺寸和横截面形状的微通道可以有效地提高性能。