Correct! “We analysed the laminin that the cells had deposited.”
Use ‘that’ whenever it is a necessary part of the sentence, and when you would not pause before it in speech (Essential or restrictive clauses).
If it simply is a break before giving fresh information, and you would pause before it in speech, use ‘which’ (or ‘who’) with a preceding comma (Non-essential or non-restrictive clause.)
“We quantified the deposited laminin, which was assembled into rose-like patterns.” Here, the patterns were not part of the quantification so it’s just an interesting aside!
Laminins are found in basement membranes. These are heterotrimeric proteins…
Basement membranes contain laminins. These are heterotrimeric proteins…
In case you don’t know… Laminins are awesome! They are a family of proteins that hold your tissues together.