"fundamentally interesting" is correct and usable in written English.
You can use it to describe something that is fascinating on a basic level. For example, "The history of the world is fundamentally interesting."
"From where I sit, the fundamentally interesting part of this whole field is what we don't yet understand about aspirin".
While the patterns were beautiful and fundamentally interesting, Penrose said he was not aware of any very successful commercial applications.
When Mr. Jobs called a reporter — he called me a few times — it was to argue, compliment or admonish, probing and searching, but all the while giving away nothing fundamentally interesting about the company.
The results are fundamentally interesting and also practically useful in various food industry and engineering fields.
This, if nothing else proves that they have found something fundamentally interesting and working.
Heteronuclear metalloenzymes catalyze some of the most fundamentally interesting and practically useful reactions in nature.
Of course, this is not to exclude the fundamentally important proposition that this kind of introduction can only ever provide a 'snapshot' for participants of an enormous and (we believe) essentially interesting territory.
In addition to the knowledge assessed by the MA, one of the important outcomes was to stimulate greater interdisciplinary and transdisciplinary research to address these issues that were not only fundamentally scientifically interesting, but also critically important for decision makers.
"But fundamentally what's really interesting about a bunch of people trapped on a weird island?
"In the newspaper, publishing and magazine world, the marriage of the Net with the old economy provides fundamentally better and more interesting information to consumers than either can individually.
Another interesting subject of fundamentally quantum nature is the coupling between plasmon and atomic or molecular exciton.
