Little dog's fur for scientist's protection (3,4)
I believe the answer is:
lab coat
'scientist's protection' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'little dog's fur' is the wordplay.
'little dog' becomes 'lab' (short for Labrador).
'fur' becomes 'coat' (an animal's coat).
'lab'+'coat'='LAB COAT'
'for' is the link.
Can you help me to learn more?
(Another definition for lab coat that I've seen is " Scientist's protective clothing (abbr)".)