The biggest obstacle to everything is dust or just not keep things clean enough. In the mornings we go prepare 8-10 circular slides. We take them over to this entirely different building and rinse them with acetone and ethanol. Then we put them in a plasma cleaner. Before producing the plasma we create a vacuum in the chamber and after waiting a minute for all the air in it to disappear we turn the vacuum off and turn on the solenoids which produce a plasma that you can actually see! I will try to get a picture of it before the summer is over but basically it looks like a purple mist. The plasma is ionized and so all the particles on the slides are attracted and pulled off. This is the most effective method to clean the slides. Some other scientists use what is called a hypersonic bath. Basically this entails putting the slides in a solution that is then vibrated at a hypersonic frequency. The drawback to this method is it can only shake off particles that are larger than its wavelength. After the slides are done we put them in a special box Rachid made that we also clean with pressurized air. And then walk back to our building. Now its important whenever we use them to only touch them on the edges and only with tweezers, which can be frustrating when youre trying to align them properly. There is always some dust on them and this is visible and bright in the video although the lifetime of its brightness is significantly shorter than that of the DNA.
Contamination can also come from our pipettes if we are not careful to use a new tip for each new solution we use. Also my hands aren't the steadiest so whenever the tip of the pipette touches the outer rim of the test tubes instead of going straight in to the solution, I also have to change the pipette tip. The same is true for the tip of the mini vacuum we use to "wash out" our slides. Everything that comes in contact with something biological (the tips, the circular slides, regular slides, and our latex gloves) all get thrown away after being used. The only exception are the metal circle things we lock the circle slide in to. THese we rinse well with ethanol and then let dry. We only have four so we can only prepare four tests at one time.
Light is almost as much of an enemy as dust. The fluorescent molecules on the DNA and the protein have to be kept in the dark as much as possible to prevent their being photo-bleached. This means we keep them wrapped p in aluminum foil and tight in our hands when we are getting them out. We also work in the dark with just one side lamp.
Using or creating a bad concentration of something. If there arent enough DNA for instance? We spent the first day just playing around with concentrations.
Once we had a bubble of air in the oil on the lens so we had to clean off the whole lens with this special liquid and special lens cleaning paper. The lens is 10,000 euros-ish so its important to be very careful so that we dont scratch it.
And then of course you can always break something. Like a circular lens for instance which I did yesterday and Rachid did today. They're absurdly fragile.
Today was similar to yesterday except I got to do some more of the stuff on my own, so I think Rachid's trust in me is increasing!
Tomorrow...a fun blog about the plans for this holiday, four day weekend!
No comments:
Post a Comment