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Dendrite cell chemotaxis in microfluidic mazes

Written by John Crabtree
Dendrite cell chemotaxis in microfluidic mazes

korean-chemotaxis

South Korean researchers have recently shown that immature dendrite cells undergo chemotactic migration through microfluidic mazes preferentially towards healthy or cancerous cells versus cell-free medium.  The new research findings, published in a Lab on a Chip article, come from Cho’s group at the Institute for Basic Science, Grybowski’s group at the Ulsan National Institute of Science and Technology, and Jeon’s group at the Pohang University of Science and Technology.

Chemotaxis is the movement of cells towards or away from chemical stimulus (attractants or repellents, respectively).  Bacteria accomplish this through biased ‘random’ walk cycles, where the cells use their flagella to move in a given direction, then stop and sense whether they have moved up or down the stimulant’s concentration gradient to determine subsequent reorientation and straight-line translation.  Migration towards attractants by dendrite cells (surveillance agents and messengers for the immune system) is well documented for mature but not immature dendrite cells.

In this study, immature cells were allowed to migrate towards cell medium (control), EpH4-Ev healthy cells or beta-MEKDD 116 cancer cells.  In one experiment series, comparisons in migration were evaluated by allowing the immature dendrite cells to migrate from a single inlet towards either of two outlets that contained two of the three cell attractants.  Attraction bias was clearly shown to be (beta-MEKDD 116) > (EpH4-Ev) > (cell medium).  In another series of experiments, different cytokines drawn from the cancerous beta-MEKDD 116 cells were compared, and the protein Gas6 was found to have the largest attractive effect.  Large numbers of replicate analyses allowed the authors to nicely quantify the confidence limits that applied to their results.korean-chemotaxis2

 

1. New Microfluidic Devices & Technology

First image of black hole: epitome of scientific collaboration

Written by John Crabtree
First image of black hole: epitome of scientific collaboration

black-hole-different-observatories Accomplishements in microfluidics and analytical chemistry are normally front and centre in this blog, but this is a nod to some great work in physics.  It turns out physics is more complicated than F = ma. 😉

There was a big splash in the media around April 10th about the first images of a black hole ever obtained, and they are indeed pretty fascinating.  What is at least as fascinating is the coordinated, collaborative effort between the astrophysics teams in several countries to generate these images.  A few editorial pieces summarise the tremendous scope of the work nicely on webpages at MIT, the Event Horizon Telescope (or EHT), and publisher IOP.  There are six open-access publications listed at the bottom of the EHT page that describe the work and its results.

The teams all belong to the EHT which is an array of radiofrequency telescopes that work in harmony to image a given target at the same time.  The resolution afforded by teaming the individual telescopes together is vastly better than that of any individual telescope.  A few images from papers that were published simultaneously on April 10 show some of the results.  The first shows several pictures of the M87 black hole taken from different observatories early in the project, before many of the efforts at noise reduction were implemented (image from Figure 4 of this paper).  array-of-different-observatoriesThe second shows the location of the different observatories in Europe, North and South America, Hawaii and Antarctica that were teamed together for the effort (image from Figure 1 of this paper).

To be able to work synchronously, all the observatories had to use precise timestamping of their images with atomic clocks.  Each observatory generated so much data, about 1 PB (PB = petabyte = 1 million GB), that it was faster to simply fly the hard drives to the Max Planck Institute for Radio Astronomy (Germany) and MIT’s Haystack Observatory (Boston, US) for the data processing.  Interestingly, the images black-hole-different-dayschange appreciably from day to day, as shown below (image from figure 15 of this paper).

Any collaborative scientific effort of this size is remarkable, all the more so given the size of the groups in different countries, funding sources from yet many more countries, etc.

 

4. Miscellany