A Microbore Tubing Based Spiral for Multistep Cell Fractionation

Inertial microfluidics: current status, challenges, and future opportunities

Inertial microfluidics uses the hydrodynamic effects induced at finite Reynolds numbers to achieve passive manipulation of particles, cells, or fluids and offers the advantages of high-throughput processing, simple channel geometry, and label-free and external field-free operation. Since its proposal in 2007, inertial microfluidics has attracted increasing interest and is currently widely employed as an important sample preparation protocol for single-cell detection and analysis. Although great success has been achieved in the inertial microfluidics field, its performance and outcome can be further improved. From this perspective, herein, we reviewed the current status, challenges, and opportunities of inertial microfluidics concerning the underlying physical mechanisms, available simulation tools, channel innovation, multistage, multiplexing, or multifunction integration, rapid prototyping, and commercial instrument development. With an improved understanding of the physical mechanisms and the development of novel channels, integration strategies, and commercial instruments, improved inertial microfluidic platforms may represent a new foundation for advancing biomedical research and disease diagnosis.

Hand-Powered Inertial Microfluidic Syringe-Tip Centrifuge

Conventional sample preparation techniques require bulky and expensive instruments and are not compatible with next-generation point-of-care diagnostic testing. Here, we report a manually operated syringe-tip inertial microfluidic centrifuge (named i-centrifuge) for high-flow-rate (up to 16 mL/min) cell concentration and experimentally demonstrate its working mechanism and performance. Low-cost polymer films and double-sided tape were used through a rapid nonclean-room process of laser cutting and lamination bonding to construct the key components of the i-centrifuge, which consists of a syringe-tip flow stabilizer and a four-channel paralleled inertial microfluidic concentrator. The unstable liquid flow generated by the manual syringe was regulated and stabilized with the flow stabilizer to power inertial focusing in a four-channel paralleled concentrator. Finally, we successfully used our i-centrifuge for manually operated cell concentration. This i-centrifuge offers the advantages of low device cost, simple hand-powered operation, high-flow-rate processing, and portable device volume. Therefore, it holds potential as a low-cost, portable sample preparation tool for point-of-care diagnostic testing.

Electricity-free hand-held inertial microfluidic sorter for size-based cell sorting

Conventional batch-top cell sorters are often bulky and expensive, and miniaturized microfluidic sorters available mostly require field generators and electricity-powered pumping systems. Therefore, the development of a low-cost, portable cell sorter that can be used in low resource settings is essential. In this study, we propose such an electricity-free hand-held inertial microfluidic sorter that can be used for the high-efficiency sorting of differently sized cells in a continuous and passive manner. The proposed hand-held sorter is composed of a wheel-shaped all-in-one syringe inertial microfluidic sorter (i-sorter) with flow stabilizer units and two spring-driven mechanical syringe drivers. The release of the compression spring in the mechanical syringe driver through a one-click operation provides the flow driving force. Passive flow stabilizer units in the i-sorter enable flow-rate-sensitive inertial cell separation for the unstable driving flow rate generated by the low-cost mechanical syringe driver. We successfully achieved sorting of differently sized particles and high-efficiency separation of rare tumor cells from the blood using the fabricated prototype. Our hand-held inertial microfluidic cell sorter has many advantages, including low device cost, simple electricity-free operation, compactness, and portability; additionally, samples do not need to be pre-labelled. Therefore, it has potential for use in low-resource settings.

Polyploid giant cancer cells: Unrecognized actuators of tumorigenesis, metastasis, and resistance

Cancer led to the deaths of more than 9 million people worldwide in 2018, and most of these deaths were due to metastatic tumor burden. While in most cases, we still do not know why cancer is lethal, we know that a total tumor burden of 1 kg-equivalent to one trillion cells-is not compatible with life. While localized disease is curable through surgical removal or radiation, once cancer has spread, it is largely incurable. The inability to cure metastatic cancer lies, at least in part, to the fact that cancer is resistant to all known compounds and anticancer drugs. The source of this resistance remains undefined. In fact, the vast majority of metastatic cancers are resistant to all currently available anticancer therapies, including chemotherapy, hormone therapy, immunotherapy, and systemic radiation. Thus, despite decades-even centuries-of research, metastatic cancer remains lethal and incurable. We present historical and contemporary evidence that the key actuators of this process-of tumorigenesis, metastasis, and therapy resistance-are polyploid giant cancer cells.