Time-dependent synthetic biological barrier material

A method of forming a thermally stable electrospun barrier comprising:

• dissolving a major fiber population in a solvent;
• dissolving a minor fiber population in the solvent;
• electrospinning the dissolved major and minor fiber populations to form a co-spun barrier;
• and
• wherein the dissolved major and minor fiber populations are dispensed through an alternating needle sequence to form an intermixed structure comprised of the major and minor fiber populations;
• wherein the major fiber population comprises at least one thermally unstable species;
• wherein the minor fiber population comprises at least one thermally stable species;
• wherein the major fiber population and the minor fiber population are co-mingled and distributed throughout the electrospun barrier;
• wherein the major fiber population and the minor fiber population are distinct and independent from each other in the electrospun barrier;
• wherein the fibers of each fiber population are not composite fibers comprising both the thermally unstable species and the thermally stable species;
• wherein the electrospun barrier exhibits limited macroscopic changes in physical and mechanical properties when exposed to thermal or mechanical stress;
• and
• wherein the minor fiber population is present in the thermally stable electrospun barrier in an amount of from 13 to 49% by weight.