Partical board has toxic chemicals in it. Unless you completely seal every interior surface I would not use it. Real wood furniture can be converted and with minimal effort can be sealed (as long as it isn't pine/cedar) but the price tag will be much higher.

If you don't like the aesthetics of PVC cages you could always add a shell to make it look better:

A few sheets of beadboard, molding, and some screws should make a nice facade.