Glycerol-plasticized bacterial nanocellulose-based composites with enhanced flexibility and liquid sorption capacity

Abstract

Bacterial nanocellulose (BNC) and two BNC-based composites with carboxymethyl cellulose or hydroxyethyl cellulose (BNC-CMC or BNC-HEC, respectively), were produced in situ by Komagataeibacter xylinus E25 under stationary conditions and plasticized with glycerol (ex situ modification). The BNC-CMC composite had the loosest structure (visible in SEM images) and was less crystalline (CI of 88.6%) than BNC (CI of 92.9%) and BNC-HEC (CI of 90.4%). Cellulose fibers synthesized by K. xylinus E25 in the presence of HEC were thinner in comparison to the fibers of control BNC while there was no difference in the fibers width between the BNC-CMC and control BNC. The glycerol-plasticized BNC, BNC-CMC and BNC-HEC membranes were flexible after drying, and absorbed high amounts of artificial exudate and water after rehydration. BNC-CMC treated with 2.5% v/v aqueous glycerol was characterized by the greatest free swell absorptive capacity (up to 19 g artificial exudate/g dry weight in 24 h) while the highest rehydration capacity (around 96% of the initial water content) was observed in case of BNC-CMC plasticized with 10% v/v glycerol and dehydrated. The in situ and ex situ modifications of BNC affected also the tensile strength. The highest values of tensile strength at break (around 152.2 N) and Young's modulus (around 290.3 MPa) were observed in case of the BNC-CMC composite plasticized with 2.5% v/v glycerol. The impact of plasticized BNC, BNC-CMC and BNC-HEC on the viability of HaCaT keratinocytes was also studied and found to be positive at glycerol concentrations up to 2.5% (v/v) that suggests their potential utility as wound dressings.

UV-Shielding films of bacterial cellulose with glycerol and chitosan. Part 2: Structure, water vapor permeability, spectral and thermal properties

“…The high moisture content of the samples and in the reduced free groups resulted in low water adsorption values. The results obtained were in agreement with behaviors previously observed in polysaccharide-based films with glycerol (Cielecka et al, 2019;Priyadarshi et al, 2018;Thakhiew et al, 2010;Lin et al, 2013).…”

UV-Shielding films of bacterial cellulose with glycerol and chitosan. Part 1: equilibrium moisture content and mechanical properties

“…The presence of the plasticizer increases the deformation capability of the polymer (lower TS, YM, T and BS values) and eases the relative movement of the chains (higher% E and DB values) (Sirviö et al, 2018;Sun et al, 2018). Similar modifications of the mechanical properties by the presence of glycerol were observed in hydroxyethyl cellulose-based films (Sirviö et al, 2018), BC-based films (Cazon et al, 2020b;Cielecka et al, 2019;Sun et al, 2018), and chitosan (Priyadarshi et al, 2018), among other polysaccharide-based films.…”

“…In literature, previous studies demonstrated the plasticizing effect of glycerol on BC films. Results indicated that glycerol interacts with the BC polymer chains, reducing the intra-and inter-molecular hydrogen bonds in the BC fibers, decreasing the stiffness and brittleness of the dried BC samples and improving their elasticity (Cazon et al, 2019a(Cazon et al, , 2020bCielecka et al, 2019;Sun et al, 2018).…”

Recent Advances and Applications of Bacterial Cellulose in Biomedicine

“…Bacterial cellulose is not routinely disseminated throughout the commercial healthcare sector as a wound dressing, despite the multitude of studies, which have been demonstrated with appropriate pre- and post-biosynthesis modifications, which enhance the overall properties of the BC to meet the specific requirements of wound dressings—for example, increased antimicrobial properties, the re-epithelialisation of wounds and shorter healing times. However, there are a few select manufacturers, located in Poland, Brazil and America, who are exploiting bacterial cellulose as a viable material for wound dressings [ 109 ]. Lohmann & Rauscher has produced the only drug-activated bacterial cellulose wound dressing by incorporating polyhexamethylene biguanide (a disinfectant) into the cellulose structure under the trade name Suprasorb ® X+PHMB.…”

“…As a result of research conducted at Lodz University of Technology, Poland, the company S2Medical AB, Sweden began the wide-scale production of bacterial cellulose wound dressings under the brand name EpiProtect ® . The main target of this dressing was for burn wounds where complete healing of first- and second-degree burns was complete after 28 days of continual dressing with EpiProtectt ® , in comparison to 32 days with silver sulphadiazine and gauze [ 109 ].…”