Articles Read

below are links to articles given to me to read:

www.dna.caltech.edu/Papers/DNAorigami-nature.pdf

http://einstein.sc.mahidol.ac.th/~jose/pdf/Moerner_Fromm_RSI.pdf

Talked to Ivan about his experiment with cell adhesion. He uses the AFM to measure the adhesive forces acting between a cell and a surface. The idea is that the cell is bound to the cantilever and bound to the surface that contains specific proteins. The cantilever then pushes and pulls on the cell. The deflection of the cantilever can be translated into force. Today, Ivan was trying to show that there is a consistancy in the cell's adhesive force. The graph shows the force vs. height of the cantilever. The sudden jumps correspond to parts of the cell losing adhesion with the surface, being ripped away. Further studies will be needed to show if the cell is simply seperating from the proteins on the surface or if the surface proteins are being ripped away. This experiment will require the unique setup in this lab, where the surface proteins will be marked with florescent dye. They will only appear if they are on or near the surface, so they will not appear if they are being ripped away from the cell. The unique setup should be able to show if they are being ripped away, and if the time intervals they are being ripped correspond to the sudden jumps in the graph.

One possible use for this would be to create synthetic substances that can change the adhesive forces in cells. Blood clotting, for example, works because of the adhesive forces between specific proteins on the surfaces of the blood cells. Perhaps medication could eventually be manufactured to help individuals who suffer from blood clots.

Project ideas:

While we have been exposed to many projects over this first week, the main theme involves the versatile use of the AMF, and combining the AMF with fluorescence spectroscopy and microscopy. An interesting project might be to build an AFM on a macroscopic scale for use in the classroom. It could be used to teach students the methods used while using an inexpensive macroscopic model. The simplest way to do this would be to build a macroscopic cantilever that deflects laser light, just as in the AFM we are looking at.

Today we scanned images of DNA samples using AFM. Parts of the process included preparing DNA samples, loading and preparing the AFM and then running the scan. The AFM has two basic modes, oscillating and contact mode. During the contact mode, the cantilever is placed at a specific angle, producing force as it bends. The system works to keep this force and angle constant by raising the cantilever as it moves over a raised surface. In the oscilating mode the image is created when the cantilever acts as a spring and the force can be measured as the surface interacts with the oscillating cantilever and can measure the change in force. At least this is my simplistic view of it. I cannot remember all the details. Olaf gave me an article that explains it well that I will read tonight.

Concept Map:

1st Day

Today we met our research group and saw the lab. While everything seems at first to be highly complex and overwhelming, there seem that there aspects of the research being done that are simple enough to possibly transfer to the high school classroom. On the simplest level, we will be working with optical microscopes. Some research being done includes looking at the "squishyness" of cell membranes of cancer cells vs. non-cancer cells. There are basic concepts of Force and springs that seem to be applied at the nano scale. The idea of working at the nano level is also intriguing. I am looking forward to getting involved and learning how the technology works along with how it is being applied to answer the big picture questions. Tomorrow, I expect to learn more about the microscopy itself and how the equipment works. The first day was a little overwhelming, but I feel confident that I will be able to work in the lab and learn new things.