a method for the preparation of biologically active materials is presented . the invention involves taking a base material such as allografts , xenografts , polymers , metals , and ceramics and combining it with a biologically active agent , such as proteins , cytokines , growth factors , and enzymes after which it is irradiated with ionizing radiation to sterilize and stabilize the material . the resulting biologically active material may then be stored at ambient temperature while maintaining its biological activity and the structural integrity of the base material . the invention is particularly useful for eliciting desired biological responses in human and animal medicine , and in certain industrial applications .