Probing large cellulose microfibril formation in cotton fiber tissue

Cellulose is the most abundant biopolymer on Earth and an essential sustainable resource to humanity. Native cellulose exists in a crystalline nanofiber, cellulose microfibril (CMF). CMFs in higher plants are believed to have identical nanoscale morphology with a fibril width of 3 nm due to the shared biosynthetic mechanisms. However, cellulose-rich plant tissues have thicker CMFs, including cotton fiber with 5-nm-wide CMFs. This size variation is puzzling and beyond the current understanding of plant cellulose biosynthesis. Here, to better understand the structural evolution of cotton CMFs during the late development stage, we will use microfocus X-ray scattering to probe the ultrastructural change of never-dried cotton fiber in various drying conditions. The results will help us understand the formation mechanism of thick CMFs in cotton. They will provide insights into the morphogenesis of higher plant CMFs and inspiration for fine-tuning the morphology of cellulose nanomaterials.