There are currently three students working in Professor Andresen’s lab, Jose, Dylan and Amlan. Each of us are working on different projects and therefore we all pretty much do our own stuff with very little overlap between what we do. When we first got into the lab, things were a little chaotic so one of the first things we did was clean and reorganize the lab. This included alphabetizing not only the sample cabinet but also the bookshelf. We also freed up three drawers worth of space that new things can now be stored in, freeing up more lab table space. This cleaning day, we worked together like a unit, it was a very productive day. Although the photo quality is not high enough to allow you to read the labels in the image below, I assure you that they are alphabetized.
The machine pictured below is called the UV-Vis machine. Dylan runs this machine almost every day to look at both nano-particle concentrations and DNA concentrations in various samples but other lab members will also use the machine when needed. The object in his hand is called a Quartz cuvette. When looking at the wavelengths over 400nm, a normal cuvette may be used. However, a normal cuvette interferes with the wavelengths that the machine must run at to view DNA, between 320nm and 220nm, so it must be used instead. This machine essentially just shoots light through the cuvette and records the intensity at each wavelength, this can allow us to identify what exactly is in the sample.
Below is an example of what the data looks like from the UV-Vis. The top graph was run from 320nm to 220nm, its peak wavelength is right around 250 and its absorbance is right around 1. This means that there is a large concentration of DNA in the sample. The second graph was run from 800nm to 400nm, its peak is around 520nm and its absorbance was around .1 at peak. This means that there are ideal gold Nano-particles in the solution but at a low concentration. It’s important to know why we used 220nm and 320nm wavelength, this is because nucleic acids absorb more strongly at 260nm while proteins absorb at 280nm which is not what we want on our results. Jose uses Beer’s Law in order to find the concentration of DNA in his samples.
Below are two pictures of our centrifuge. It has temperature and speed regulation. Dylan’s experiment should be running at room temperature but Jose’s must be run at 4 degrees Celsius. This causes some fighting in the lab, careful planning must be coordinated to avoid such problems. On heavy centrifuging days, we try to politely steal a centrifuge from Professor Thompson’s lab.
The next image is the crown jewel of our lab, the ICP-OES, which stands for Inductively coupled plasma optical emission spectrometry. So, this machine tells you exactly what is in your sample and at what concentrations. First it heats up a green plasma that you can see through a little window on the machine, it gets as hot as the surface of the sun. Don’t worry, we are not in danger around the machine, the plasma stays inside. Then it starts spraying your sample through the plasma, this breaks down all chemical bonds and sends the sample into the next part of the machine where it can determine what is in the sample. The machine takes a long time to warm up and run, so if you must use it you really must plan your day around using the machine. It also comes with two very loud gas canisters, one containing Argon and the other liquid nitrogen. These must be replaced regularly or else we cannot run the machine. Sometimes chemists from across the street come to give us company in our lab while using the machine.
Below is one of our labs most value resources, Milli-Q water. The building we’re in, Masters hall, does not have its own Milli-Q water, so if we want more water we must drag it all the way to professor Frey’s lab in the Science Center. Some of the people in our lab use much more water than others, were talking like 99% or more, then they try to get other people who used much less water to fill it back up. However, other lab members find this practice unacceptable. To settle this dispute, we typically meet right after work to fight and whoever loses must fill it up the next day.
Amlan, on the other hand, works on the enthalpy changes associated with DNA binding and condensation. He uses the Isothermal Titration Calorimetry technique in order to record the heat changes due to DNA binding with certain cationic ligands. You won’t even find him in our lab for most of the day. He spends most of his time working with the Nano-ITC machine in the Physical Chemistry lab in Science Center. In rare instances, he will stop by our lab to pick up a few DNA samples and then off to the P. Chemistry lab again. In case you are wondering what the Nano-ITC machine looks like, here is a picture:
Gettysburg College is going through a lot of construction right now. We are gaining a new building and losing an old one. Luckily, Andresen’s lab has the best view of this construction. Whenever we are curious we can just peep out the window and catch all the construction workers over there on the roof doing their thing. Having this incredible view from our workplace really helps increase morale and general productivity. Below is the picture from the window, wow.
The next picture depicts the tools used to run the agarose gel, which Jose runs. The gel is used to separate DNA based on its length in base pairs, smaller segments move farther then longer segments. The separation of DNA is achieved due to the negative charged of DNA backbone, the gel and the samples are run vertically at a constant voltage with a running buffer containing SDS. SDS is used in the buffer to denature the proteins and bind with them. This process usually takes about 4-5 hours and them the samples are ready to be view in a special UV light.
The next pictures shows a new tradition that was created and inspired by Andresen’s lab and has spread not only throughout the physics department but also to the entire X-SIG program, our goal is to one day be able to make this tradition not only to those working during the summer but to the whole school.