In this work, we demonstrate the differentiation of demodulated multifrequency signals from impedance sensitive microparticles when targeting surface receptors on neutrophils in a microfluidic impedance cytometer. These scheme uses a single signal input and detection configuration, and machine learning can differentiate particle types with up to 82% accuracy.
Small water microdroplets in microfluidic systems have a high surface charge density resulting from charged surfactants. As a result, an electric double layer forms inside the droplet. Depletion of ions from the center of the droplet to form the double layer can shift the concentration of ions dramatically from that of the microdroplet precursor solution. Here we show numerical solutions to the Gouy-Chapman model in spherical coordinates. Some notable effects include: 1) large percentages of the microdroplet volume experience very large DC electric fields; 2) many ions get forced into a Stern layer giving dramatically different conditions from the bulk.
In metastatic cancer, the secondary microenvironment consists of numerous cell types, each signaling with, and potentially supporting, the disseminated tumor cell. However, in vitro models have thus far been limited in their complexity, ultimately hindering study. To overcome this, we report the optimization and application of a high-throughput method, DNA-directed patterning, to pattern different cell types from the bone marrow microenvironment for the study of prostate cancer proliferation within this environment. We show that cells in our patterned microenvironment maintain their phenotype and behavior. Moreover, we demonstrate the successful introduction of prostate cancer cells in our microenvironment to investigate dormancy.
Circulating tumor cells (CTCs) are promising markers to determine cancer patient prognosis and track disease response to therapy. We present a multi-stage microfluidic device we have developed that utilizes inertial and Dean drag forces for isolating CTCs from whole blood. We demonstrate a 94.2% ± 2.1% recovery of cancer cells with our device when screening whole blood spiked with MCF-7 GFP cells.
We propose a method to separate photosystem I crystals based on size using a combination of dielectrophoresis (DEP) and electrokinesis (EK) within a microfluidic device. In this work, a model system utilizing polystyrene beads of two sizes is employed to observe the effects of DEP and EK on particles as they pass through a microsorter via electroosmosis. Particle counting and fluorescence intensity measurements are used for quantitative analysis of experimental data. For comparison, numerical simulations were performed for further confirmation that the proposed device is capable of sorting particles based on their size. Our experimental and theoretical results are in agreement and show a high degree of sorting efficiency between both particle types making this a promising solution for protein crystal sorting.
