Real-Time Detection and Capture of Invasive Cell Subpopulations from Co-Cultures.

Invasion and metastatic spread of cancer cells are the major cause of death from cancer. Assays developed early on to measure the invasive potential of cancer cell populations typically generate a single endpoint measurement that does not distinguish between cancer cell subpopulations with different invasive potential. Also, the tumor microenvironment consists of different resident stromal and immune cells that alter and participate in the invasive behavior of cancer cells. Invasion into tissues also plays a role in immune cell subpopulations fending off microorganisms or eliminating diseased cells from the parenchyma and endothelial cells during tissue remodeling and angiogenesis. Real-Time Cellular Analysis (RTCA) that utilizes impedance biosensors to monitor cell invasion was a major step forward beyond endpoint measurement of invasion: this provides continuous measurements over time and thus can reveal differences in invasion rates that are lost in the endpoint assay. Using current RTCA technology, we expanded dual-chamber arrays by adding a further chamber that can contain stromal and/or immune cells and allows measuring the rate of invasion under the influence of secreted factors from co-cultured stromal or immune cells over time. Beyond this, the unique design allows for detaching chambers at any time and isolating of the most invasive cancer cell, or other cell subpopulations that are present in heterogeneous mixes of tumor isolates tested. These most invasive cancer cells and other cell subpopulations drive malignant progression to metastatic disease, and their molecular characteristics are important for in-depth mechanistic studies, the development of diagnostic probes for their detection, and the assessment of vulnerabilities. Thus, the inclusion of small- or large-molecule drugs can be used to test the potential of therapies that target cancer and/or stromal cell subpopulations with the goal of inhibiting (e.g., cancer cells) or enhancing (e.g., immune cells) invasive behavior.

Tuning the Polarity of MoTe2 FETs by Varying the Channel Thickness for Gas-Sensing Applications.

In this study, electrical characteristics of MoTe2 field-effect transistors (FETs) are investigated as a function of channel thickness. The conductivity type in FETs, fabricated from exfoliated MoTe2 crystals, switched from p-type to ambipolar to n-type conduction with increasing MoTe2 channel thickness from 10.6 nm to 56.7 nm. This change in flake-thickness-dependent conducting behavior of MoTe2 FETs can be attributed to modulation of the Schottky barrier height and related bandgap alignment. Change in polarity as a function of channel thickness variation is also used for ammonia (NH3) sensing, which confirms the p- and n-type behavior of MoTe2 devices.

Using electrospun poly(ethylene-oxide) nanofibers for improved retention and efficacy of bacteriolytic antibiotics.

The aim of this study was to demonstrate targeted delivery of protein-based bactericidal antibiotics using electrospun polymer nanofibers. Previous studies have utilized electrospinning to create nanofibers for the localized delivery of therapeutic agents, including non-steroidal anti-inflammatory drugs (NSAIDs) and low molecular weight heparin. By employing established electrospinning techniques, nanofibers of varying diameters (100-500 nm) were generated from a 0.05 % solution of poly(ethylene-oxide) (PEO) and the antimicrobial peptide, LL-37 was incorporated into the nanofiber meshwork. Initial experiments determined that the strong electric fields caused by electrospinning do not disrupt the antimicrobial properties of LL-37, thus justifying the application of LL-37 as an electrospun component. Disk diffusion assays and especially bacterial filtration studies with E. coli were conducted to quantify the drug delivery potential of the nanofibers. Disk diffusion revealed a small zone of inhibition of about 1 mm around the LL-37-incorporated nanofiber disk. Filtration tests demonstrated that electrospun PEO fibers were capable of delivering LL-37 consistently while still maintaining their antimicrobial abilities.