Complex sentence: They also created a skin from shark cartilage and cowhide that, when dried and sterilized, could be made into a thin membrane in which materials could pass through, like they would pass through the dermis.
Split into simpler sentences: They also created a skin from shark cartilage and cowhide. When this skin dried and was sterilized, could be made into a thin membrane in which materials could pass through, like they would pass through the dermis.