Circulating tumor cells (CTCs) are tumor cells that are shed from cancerous tumors into the circulatory systems. CTCs are present in early-stage cancers and are reported to relate to disease prognosis. In recent years, CTCs have drawn increasing attention in both academic and industrial research, as they offer opportunities for the early detection, monitoring, treatment evaluation of cancer and its metastasis 1.
CTCs are challenging to capture, isolate and characterize in nature. First, CTCs are extremely rare in patients’ blood samples. One CTC usually exists among a background of millions of blood cells. Furthermore, CTCs are highly heterogeneous in physical characteristics and biological properties. No separation technology which is based on a single capture mechanism can produce pure and representative CTC subpopulations. In the traditional liquid biopsy, CTCs are isolated either by immunoaffinity strategies or by biophysical features differentiation. However, existing macro-scale isolation systems suffer important drawbacks, such as low capture efficiency, incomplete automation and low viability of captured CTCs 2. As a promising alternative, microfluidic technologies have gained tremendous interest in the field. Microfluidic technologies create devices that are at or smaller than the cellular length scale and enable accurate capturing and manipulation at single cell level. These technologies also offer precise control of fluid flow, which can greatly facilitate affinity reactions and physical separation. Moreover, on a microfluidic chip, CTC capturing and next-step analysis can be integrated to minimize intermediate sample handling and shorten the processing time. Above all, microfluidic approaches allow gentle isolation of live cells and thus enable many downstream analyses that rely on captured live CTCs 3. (more…)
Everyday clients share their microfluidic designs or products with contract manufacturing companies. Interestingly the designs can be classified to two types, let’s call them Type A or B, based on whether they exploit micron-size specific behavior of fluids or not. These small scale phenomena include surface tension, electrical, magnetic or shear force, etc… which may behave differently in a 30 micron dia. channel compared to a 1mm dia. channel for similar designs.
Type A devices exploit the micron scale behavior to achieve a novel function. A Type A product offers something new that probably is not feasible if the design is scaled 10 times larger. Type A designs are therefore innovative or perhaps disruptive. On the other hand, Type B devices offer to miniaturize, integrate or automate existing fluidic products or processes. The value proposition for type B products may include “cheaper”, “faster” or “more accurate” words.