Surface-Structured Bacterial Cellulose with Guided Assembly-Based Biolithography (GAB)

Abstract

A powerful replica molding methodology to transfer on-demand functional topographies to the surface of bacterial cellulose nanofiber textures is presented. With this method, termed guided assembly-based biolithography (GAB), a surface-structured polydimethylsiloxane (PDMS) mold is introduced at the gas-liquid interface of an Acetobacter xylinum culture. Upon bacterial fermentation, the generated bacterial cellulose nanofibers are assembled in a three-dimensional network reproducing the geometric shape imposed by the mold. Additionally, GAB yields directional alignment of individual nanofibers and memory of the transferred geometrical features upon dehydration and rehydration of the substrates. Scanning electron and atomic force microscopy are used to establish the good fidelity of this facile and affordable method. Interaction of surface-structured bacterial cellulose substrates with human fibroblasts and keratinocytes illustrates the efficient control of cellular activities which are fundamental in skin wound healing and tissue regeneration. The deployment of surface-structured bacterial cellulose substrates in model animals as skin wound dressing or body implant further proves the high durability and low inflammatory response to the material over a period of 21 days, demonstrating beneficial effects of surface structure on skin regeneration.

3D bacterial cellulose biofilms formed by foam templating

“…Mannitol media was used to increase the cellulose yield. 35 Cultures of G. xylinus ATCC-700178 4 were grown in standing cultures at room temperature. Inoculation of cultures was done at 1%.…”

“…Conventionally, BC is formed at the air–water interface as a biofilm from Gluconacetobacter xylinus , a surface-dwelling and oxygen-dependent bacterium. The result of such biofilm growth is a highly interconnected BC nanoporous network, which can be used directly 4 in, e.g., the biomedical industry, 5,6 as the native pellicle closely resembles the structure of collagen. 7 BC is biocompatible and has been successfully implanted with no fibrotic tissue formation.…”

“…7 BC is biocompatible and has been successfully implanted with no fibrotic tissue formation. 8 This property makes the naturally formed structure of BC an excellent candidate for artificial skin products, 8 wound dressing, 9–12 surface patterned implants, 4 and blood vessels, 7,13 where cells have already shown noteworthy cell growth properties. 7,14 Such self-grown BC scaffolds have been formed by exploiting the biofilm formation at the water–air interface to create a 3D shape by using silicone-based molds, 15 hydrophobic surfaces, 16,17 3D printing, 18 and emulsions.…”

Progress in development of bioderived materials for dermal wound healing

“…Another shortcoming may be the difficulty in forming BC in the desired geometries. Bottan et al could obtain nanofibers with the desired geometrical characteristics through guided assembly-based biolithography (GAB) and were thus able to effectively control the cellular activities that are fundamental to skin wound healing [12]. …”

Nanofibrous Scaffolds as Promising Cell Carriers for Tissue Engineering

“…These materials serve as wound dressings, carriers for drug delivery, preparations for treatment of ophthalmological disorders, membranes for prevention of postoperative adhesions, meshes for hernia repair, materials for hemostasis, membranes for hemodialysis, and also as materials for plastic, reconstructive, and aesthetic surgery (for a review, see [108][109][110]). For tissue engineering, including skin tissue engineering, cellulose is promising due to its relatively good mechanical properties, low immunogenic properties, high biocompatibility, and water-holding ability [111,112] (for a review, see [109,110]). However, in its pure natural form, cellulose is nondegradable in the mammalian organism, while in tissue engineering, particularly that of skin, degradability of material scaffolds is necessary in order to achieve perfect skin regeneration without scar formation.…”