A Close-Up Look at Cotton Fibers

By Jill Lee
May 21, 1997

It’s been 5,000 years since cotton fiber was first woven in the Indus Valley in what is now Pakistan, so you might think researchers in this era of DNA fingerprinting and genetic engineering would have long since seen everything cotton has to show.

But an atomic force microscope has made it possible for scientists with USDA’s Agricultural Research Service to see cotton fibers magnified 170,000 times their actual size. This gave the scientists their first three-dimensional look at the cellulose chains that make up cotton’s fiber. These chains, called microfibrils, are so small that it takes nearly 1,000 of these strands to make a single cotton fiber.

Working with scientists at the University of Southwestern Louisiana, the ARS researchers were able to obtain high-resolution images of the cotton’s primary and secondary cell walls, as well as pictures of the microfibrils. This will help these researchers to fully explore how a fiber’s structure dictates its strength and other properties.

The new view of cotton could yield important secrets, such as how enzymes interact with cotton. Enzymes are gaining favor with detergent manufacturers and textile producers because they can remove stains and keep fabric looking smooth. But some enzymes can cause fiber wear and interfere with the cloth’s dyeability.

The atomic force microscope could benefit future breeding efforts because it lets researchers pinpoint subtle distinctions between good versus outstanding cotton fiber. Another plus: With the AFM, fiber samples can be studied in their natural state and don’t have to be coated, stained or otherwise altered. These pre-treatments can mask or destroy some surface characteristics of the samples.

Scientific contact: Barbara Triplett, ARS Southern Regional Research Center, New Orleans, La., phone (504) 286-4275, btriplet@nola.srrc.usda.gov; Thomas C. Pesacreta, University of Southwestern Louisiana, Lafayette, La., phone (318) 482-5233, tcp9769@usl.edu