Radially cross-aligned nanofiber membrane

A fiber membrane, comprising electrospun fiberizeable material in at least three adjacent layers of nanofibers, each layer comprising a plurality of aligned nanofibers oriented at oblique angles relative to nanofibers in adjacent layers, said plurality of aligned nanofibers in each layer extending from a first membrane edge to a second membrane edge, wherein a plurality of aligned nanofibers in each layer cross a plurality of aligned nanofibers in adjacent layers at a plurality of distinct points of intersection, forming a crossing at each distinct point of intersection consisting of three crossing nanofibers extending directionally as six radials from each of said distinct points of intersection, wherein relative cross-alignment angles between said six radials at each distinct point of intersection are in the range of 50 to 70 degrees, and wherein said relative cross-alignment angles of said aligned nanofibers and spacing between said aligned nanofibers each have a specific average numerical value in said membrane, and wherein said aligned nanofibers in each said layer comprise at least one of solid, hollow, or core-shell fiber, and wherein said nanofibers further comprise a polymeric material and a chromogenic agent responsive to enzymatic activity, and wherein said polymeric nanofibers further comprise an absorbable and biodegradable polymer that is enzymatically or nonenzymatically decomposed, yields no toxic decomposition product, and has ability of releasing a drug.