A fluid-filled prosthetic implant having the properties of a gel-filled implant. The prosthetic implant includes a soft flexible shell defining an inner chamber and having a predetermined volume when the shell is filled or inflated. A quantity of dry nanoparticles is introduced into the inner chamber during manufacture. A surgeon inserts the flexible implant shell into a body cavity, and then utilizes a syringe or other means to deliver a fluid to the inner chamber of the shell. The fluid mixes with the quantity of dry nanoparticles to form a gel, for example, a hydrogel. The hydrated nanoparticles provide to the implant the desirable properties of a gel-filled implant. In this way, the incision used can be smaller than that for a filled implant, but the resulting prosthesis is more natural than a typical saline-filled implant.
