Friday was a busy day for me at Applied Biophysics. I learned how to plasma etch an array, interpreted the data from my 96 array experiment last week, and began my newest project: co-culturing. 

Plasma etching:

At Applied Biophysics, we use plasma etching to sterilize electrode arrays. On Friday, Dr. Keese put me in charge of the etching machine! First, I placed my array (an 8W10E+) into the chamber that will be pumped down to create a vacuum. We then pumped oxygen into this low-pressure chamber. After a few repetitions of pumping down the chamber and adding gas, we were able to start the plasma. Plasma is known as the fourth state of matter, because it is not a solid, liquid or gas. It is instead a mixture of atoms, ions, and free radicals. We sent an electrical charge through the chamber to create the plasma. The plasma ions become activated by this electrical field, and begin to vibrate and glow a white to purple color.  The vibrating ions essentially “scrub” the arrays in the chamber, leaving them sterile. Here is a picture of the plasma we created inside the chamber (and a super nerdy picture of me in front of the etcher):

Data from last week:

Last week Dr. Keese and I created a 96 array dilution series, with half MDCK-II cells and half BSC-I cells. Here is our graph using the ECIS software: 

Kind of crazy looking! Dr. Keese added a wound to the cells at 48 hours, which can be seen in the dip and recovery of the green and dark blue lines. The rainbow series of dots in the left hand column is the layout of the array wells. Columns 1-6 are MDCK-II cells, and 7-12 are BSC-I cells. Each column has same type and about the same concentration of cells, therefore we can group each column (take the average of all wells per column), making a much more manageable graph:

As you can see, the lines that are a shade of blue (representing the MDCK-II cells) take much more time to attach to the surface of the wells and form a confluent layer compared to the BSC-I cells. 

Co-culturing:

On Friday, I began my own study on the subject of co-culturing. Co-culturing cells means growing two different cell types together in one culture (or in my case, well). By studying cells in this way, we are able to see how cells interact with one another, in this case, how BSC-I cells will affect MDCK. Will one cell type overtake the other? Will the cells grow in isolated groups? Will they together form an evenly distributed confluent layer? To answer these questions, I created a dilution series, (explained in last week's post), diluting MDCK cells with BSC-1. I filled four tubes with 1ml of MDCK cells, and then added 1ml of BSC-I to the second tube. I then mixed the contents of that tube, took 1ml of the mixture, and dispensed it into the next tube. The overall array had 2 wells of pure MDCK cells, 2 wells of a 50/50 mixture, 2 of .25/.75, and 2 of .125/.875. I am looking forward to seeing these results next week!