WebZine
2016.12
What's New
Human Cells Eat Nanowires
By Emily Waltz
Posted 19 Dec 2016 | 14:00 GMT
Drop silicon nanowires and human cells into the same petri dish, and you’ll see something extraordinary: The cells will eat the nanowires. Researchers at the University of Chicago recorded the phenomenon, and reported it Friday in the journal Science Advances.
The group aims to harness that knowledge to develop a new means of drug delivery or bioelectronic therapy. “We want to do something that is special,” says Bozhi Tian, a materials scientist at the University of Chicago. “We’re trying to develop a bioelectronic device that is intracellular” and can control individual parts of the cell, he says.
Carbon Nanotubes Make New Approach to Microfluidics More Effective
By Dexter Johnson
Posted 16 Dec 2016 | 21:00 GMT
Circulating tumor cells (CTC) are key early indicators of metastasis, which is the process by which cancer cells move from one organ group in the body to another. Once cancer spreads, the prognosis is generally not good. So, early identification of CTCs can help prevent them from creating new colonies of malignant cells.
Researchers at Worcester Polytechnic Institute (WPI) in Massachusetts have developed a new approach to microfluidics to detect CTCs in blood. The WPI researchers believe that their technique could form the basis of a simple lab test for quick detection of early signs of metastasis and help physicians select treatments targeted at the specific cancer cells identified.
Current microfluidic techniques used in tumor cell isolation have been dependent on flow rate and require off-chip post-processing. The WPI researchers’ technique employs static isolation of tumor cells from the blood by fractionation of the blood into small droplets.
Silicon nanowires are biocompatible, highly conductive, and so thin they are essentially one-dimensional. Inside human cells, they could potentially be used to do a lot of things. They could record the electrical communication between structures inside the cell—signals passed from one organelle to another. They could electrically stimulate those organelles for therapeutic purposes.
Or the nanowires could carry small molecule drugs and deliver them directly to cells, bypassing some of the body’s natural barriers. The fact that the cells consume the nanowires naturally, without any kind of special treatment, and without damaging themselves, makes it that much more useful.
But before Tian’s group can turn the phenomenon into a tool, they must first understand how exactly a cell will eat a piece of silicon nanowire, and what happens to it once it’s inside the cell. That’s what the group did in today’s report.
Using both an electron microscope and a specialized optical imaging tool designed by the team, the group recorded the eating of the nanowires in detail. It appears that the cell’s outer membrane folds itself like a pocket, grabs the nanowire, and envelops it in a membrane-lined bubble. The process is called phagocytosis; it’s the same method used by immune cells to grab a bit of bacteria and swallow it up.
In research described in the journal Nanotechnology, the WPI researchers were able to create a chip design in which antibodies are attached to an array of carbon nanotubes at the bottom of a tiny well in the chip. The chips have an array of these tiny wells, each about three millimeters across.
When the blood droplets are put into the well, the heavier cancer cells drop to the bottom where they become attached to the antibodies. Each of the wells holds a specific antibody that will bind to one type of cancer cell. The chip’s electrodes detect electrical changes that occur when the cancer cells are captured by the antibodies.
Using an array of antibodies makes it possible to identify several different types of cancer cells within a single blood sample. To put that in perspective, the researchers could fill 170 wells with just 0.85 millileter of blood. The chips were able to capture between one and a thousand cells per device, equating to an efficiency of between 62 and 100 percent.
