Your essay forum title drew me to read it - how more reliable and cheaper technology could improve medical help in third world countries ..."
I thought "What a great subject and combination for a major"" But then I didn't really get the answer (of your intended major) until almost the end of the essay. It is important to answer the prompt from the first sentence to better focus the reader on where you are going and makes it easier to follow your examples. Only by the time I got to the example of the CAT scans could I conclude that you were interested in medical equipment technology, but then you said work in "biological sciences" is appealing.
I think it would make the essay more focused (and powerful) if you could specify if you were more interested in medical technology or medical care.
For your closing example - what is "
carbon fullerenes" please explain. And who is the WE you refer to below (in red:)
Since then, we have been working diligently on trying to generate these fullerenes.