Methods are provided for producing a bioscaffold from natural tissues by oxidizing a decellularized tissue to produce a bioscaffold having pores therein. The pore size and porosity is increased to better accommodate intact cells so that live cells can better infiltrate and inhabit the bioscaffold. The bioscaffold may be freeze-dried or lyophilized, sterilized and (optionally) aseptically packaged for subsequent use. A further aspect of the present invention is a bioscaffold produced by the processes described herein. Methods of treatment using the bioscaffold as a graft or as a biomedical implant for implantation are also provided. Also provided are methods of seeding a bioscaffold with mammalian cells, wherein the seeding carried out either in vitro or in vivo, and wherein a bioscaffold produced as described herein is utilized for said seeding.