Scientists say they are closer to learning how to make artificial silk that could bring medical and materials advances, but some obstacles remain.

Researchers have determined natural silk, stronger for its weight than Kevlar or steel, is "a relatively simple protein processed from water," but exactly how spiders and silkworms produce the material is still a mystery, an article in the journal Science says.

Researchers want to gain a better understanding of what silk is and how it's made, hoping to consistently replicate and enhance its production synthetically, the article said.

Scientists know spiders and silkworms pull silk out of special glands. Spiders pull it with their legs, while silkworms perform a "dance" with their heads to create the silk threads.

Despite this knowledge, Tufts University researchers Fiorenzo G. Omenetto and David L. Kaplan say, "There are still significant knowledge gaps in understanding how to reverse-engineer silk protein fibers."

Figuring out how to artificially replicate and modify silk could lead to breakthroughs in medicine and other fields, the researchers say.