Investigation of the supramolecular structure of never dried bacterial cellulose

Abstract

Supramolecular structure of initially wet bacterial cellulose of Acetobacter xylinum has been investigated by X‐ray scattering including synchrotron radiation, transmission electron microscopy, and 13C‐CP/MAS‐NMR‐spectroscopy. As a result a model is given of never dried swollen microfibrillar ribbons consisting of 5 to 12 waterfree Iα‐crystalline subunits with a cross‐section of about 7 nm × 13 nm and of water solvating the subunits. Lateral aggregation of these crystalline units was found along the smaller (110)‐lattice planes with a layer of water between adjacent crystallites. The NMR‐spectrum of wet bacterial cellulose exhibits an additional C‐1 line component indicating cellulose‐water interactions. During drying lateral dimensions of the microfibrillar ribbons, crystallite sizes, as well as the overall crystalline order decrease, whereas the Iα/Iβ‐ratio of about 80/20 remains approximately unchanged. Conclusions were drawn with regard to the early states of structure formation of bacterial cellulose.

X-ray texture investigations of bacterial cellulose

“…The width of the flat fibrillar ribbons is in the range from 72 nm to 175 nm with an average of 116 nm in accordance with our earlier results from transmission electron microscopy. [6] 4. Discussion…”

“…99 wt.-% water) with hydrated nano-fibrils of pure crystalline cellulose I as shown by synchrotron investigations. [6] Bacterial cellulose membranes exhibit remarkable mechanical properties, good chemical stability, high water absorption capacity, and a good biocompatibility, enabling interesting medical applications, [7] among others. Both with regard to the principles of structure formation and the mechanical properties of a high-tech bacterial cellulose material, the orientational state plays an important role.…”

Novel bilayer bacterial nanocellulose scaffold supports neocartilage formation in vitro and in vivo

“…BNC is a natural biopolymer synthesized by various bacteria species, particularly Gluconacetobacter xylinus [16,17]. Its three-dimensional and interconnected network is composed of highly hydrated nanofibrils ranging from 70 to 140 nm in width, similar to collagen fibrils found in extracellular matrix (ECM) of several tissues, with high tensile strength [11,18]. BNC is considered a hydrogel since it is mostly composed of water in its native state (99%).…”

Structure elucidation of uniformly 13C-labeled bacterial celluloses from different Gluconacetobacter xylinus strains

“…As a model substance for the investigation of biosynthesis and crystallization of native cellulose, bacterial cellulose (BC) from Gluconacetobacter xylinus (previously referred to as Acetobacter xylinum) was used (Brown et al 1976; Kuga and Brown 1991). Never-dried BC is a highly swollen biopolymer with approximately 99 wt.% of water (Fink et al 1997), and was investigated in dependence on the drying conditions (Bohn 2000; Udhardt et al 2005). It could be shown that the biosynthesis of cellulose macromolecules was connected with their self assembling.…”