Controlled release of VIP from PLGA microparticles was accomplished and varied through use of different polymer molecular sizes, addition of solutes to the inner aqueous phase, and use of our computer model. Released VIP from microparticles appeared to be bioactive and caused DCs to produce more CCL22 than DCs treated with blank particles at 7 and 24 hours. Additionally, DCs treated with VIP microparticle releasates recruited higher percentages of FoxP3+ T-cells in in vitro chemotaxis studies. Testing in a mouse model in vivo indicated that VIP microparticles have significant therapeutic potential to treat periodontal disease by reducing the bone loss in infected mice relative to the blank group.