The most common and most likely answer to this crossword clue is the 8 letter word ISOLATES
I
S
O
L
A
T
E
S
Buddy explains!

The straight part
We know that "makes interaction impossible" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case makes interaction impossible = isolates.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ISOLATES mean?
ISOLATES noun- Something that has been isolated.
- To set apart or cut off from others.
- To place in quarantine or isolation.
- To separate a substance in pure form from a mixture.
- To insulate, or make free of external influence.
- To separate a pure strain of bacteria etc. from a mixed culture.
- To insulate an electrical component from a source of electricity.