Tumors can shed thousands of cells into the circulation daily. These circulating tumor cells (CTCs) are heterogeneous, and their phenotypes change dynamically. Real-time monitoring of CTC phenotypes is crucial to elucidate the role of CTCs in the metastatic cascade. Here, we monitor phenotypic changes in CTCs in mice xenografted with tumors with varying aggressiveness during cancer progression and a course of chemotherapy to study the metastatic potential of CTCs and changes in the properties of these cells in response to treatment. A new device that enables magnetic ranking cytometry (MagRC) is employed to profile the phenotypic properties of CTCs. Overall, CTCs from metastatic xenografts in mice display dynamic and heterogeneous profiles while non-metastatic models had static profiles. Decreased heterogeneity followed by a reduction in metastasis incidence was observed after a course of chemotherapy administered to highly metastatic xenografts. Phenotypic profiling of CTCs could be employed to monitor disease progression and predict therapeutic responses.
In
immunobead-based assays, micro/nanobeads are functionalized
with antibodies to capture the target analytes, which can significantly
improve the assay’s performance. The immunobead-based assays
have been recently combined with microfluidic mixing devices and customized
for a variety of applications. However, device design and process
optimization to achieve the best performance remain a substantial
technological challenge. Here, we introduce a computational model
that enables the rational design and optimization of the immunobead-based
assay in a microfluidic mixing channel. We use numerical methods to
examine the effect of the flow rates, channel geometry, bead’s
trajectory, and the analyte and reagent characteristics on the efficiency
of analyte capture on the surface of microbeads. This model accounts
for different bead movements inside the microchannel, with the goal
of simulating an actual active binding environment. The model is further
validated experimentally where different microfluidic channels are
tested to capture the target analytes. Our experimental results are
shown to meet theoretical predictions. While the model is demonstrated
here for the analysis of IgG capture in simple and herringbone-structured
microchannels, it can be readily adapted to a broad range of target
molecules and different device designs.
The requirement for rapid, in-field detection of cyanotoxins in water resources necessitates the developing of an easy-to-use and miniaturized system for their detection. We present a novel bead-based, competitive fluorescence...
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