Is it permissible to enter into negotiations with an interest-based bank to facilitate interest-based loans for doctors to purchase medical equipment, knowing that this might make me a participant in the sin?

It is not permissible to negotiate with the bank to provide usurious loans, due to the assistance in sin and the approval of evil therein. The Messenger of Allah, may Allah's prayers and peace be upon him, cursed the one who consumes Riba, the one who feeds it, its scribe, and its two witnesses, for they are all equal in sin.