ABOVE IS MY FINAL CONCEPT MAP

Interesting stuff happening the last few days in lab. We are looking at cancer cells and precancerous cells. The confocal microscope is used to image the cells and the AFM is then used to test the rigidity of the cells, giving a force vs. depth graph. The slope of the graph is then analyzed to determine the "squishyness" of the cell in Force per cm. Generally, cancer cells are softer than normal cells but it is predicted that the softness should increase as cells go from normal through various precancerous stages to cancerous cells. The AMF pokes the cells in various places spread on the surface and each poke is analyzed.

With the newly installed temperature controlled stage, cells are able to be kept at body tempertature while on the stage, increasing the useful lifetime from a couple of hours to up to 8 hours before they die.

Cells are all huma esophogus cells.

Today in class we discussed RTOP. We were asked to compile a list of items that could be scored that could be observed in the classroom.. Our list consisted of:
Lesson Plan
Classroom Management
Student Engagement
Assessment
Pacing
Application
Use of technology

Cancer Cells

We are waiting for samples of precancer cells to test. While it has been shown that cancer cells have different physical properties from normal cells, speciically in the squishyness of the cells, it is believed that precancer cells will show a difference as well. The goal of the experiments is to show a progression in this property from normal cells to early precancerous cells to late precancerous cells to cancer cells. The AFM will record the data (hopefully) and combined with florescence techniques, may come the possibility of creating 3D images of these cells. The testing of these cells will continue all week, but the samples are late to arrive.

Lesson Idea

Lesson during Optics and Microscopy Unit:

1. Histroy of microscopy and scales

2. Explain the basics of AFM and how images are obtained. This can include video on basics of AFM

3. Students will design and build a macroscopic version of an AFM. They will be graded on how well they are able to mirror a real AFM, how sensitive they can make it, and how well they are able to obtain an "image" using their macroscopic AFM. Students will also need to use prior concepts and apply such as optics, spring constants, ect. depending on how they build their AFM.

Students will work in groups of 3 or 4, gather their own materials, and construct their AFMs in class. Paperwork will include schematic drawings of their design, and written explanation of the key features and how they mirror the features of a real AFM. Simple Coffee Cup design will be shown as an example to be improved upon.

Students will need to test their designs by "imaging" an unknown object (in a box or somehow hidden) and determining its stucture using their AFM.

Several different methods are expected. Hopefully the results will yield well constructed and not so well constructed versions using all types of designs.

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.