Was it a wise decision on Antonio part to sign a bond over a pound of his flesh?

Not really, no. Antonio has clearly made a very foolish decision in agreeing to bind himself to the bond and Shylock's onerous conditions. But Antonio's decision, though strange to us, does have a certain logic to it. In signing up to this potentially deadly deal, Antonio is expressing just how close his friendship to Bassanio is. He knows that his friend needs to get his hands on some ready cash if he's successfully going to woo Portia. This might not seem like a good reason for someone to risk his life, but we must recognize the social values of the time. Bassanio is a young man, romantic and deeply in love. It was considered perfectly normal at that time for men of Bassanio's age and status to get themselves into debt in order to secure a lady's hand in marriage.
Also, there is an element of pride in Antonio's decision to be bound to Shylock's deal. He is an honorable man; and to a large extent defines himself in opposition to Shylock. For instance, he's depicted as the soul of generosity and, unlike Shylock, does not lend money at interest. By agreeing to a bond that may potentially end in death, Antonio is showing Shylock that he is the better man.