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Bacterial cellulose (BC) was obtained by static cultivation using commercial BC gel from scoby. BC membranes (oven dried and freeze-dried) were swelled with 8% NaOH, in absence and in presence of ultrasound (US), for 30, 60 and 90 min. The influence of swelling conditions on both physico-chemical properties and molecules entrapment was evaluated. Considering the highest levels of entrapment, an optimum swelling procedure was established: 8% NaOH for 30 min. at room temperature in the presence of US. Native and PEGylated laccase from Myceliophthora Thermophila was immobilized on BC membranes and a different catalytic behaviour was observed after immobilization. Native laccase presented activity values similar to published reports (5-7 U/gBC) after immobilization whereas PEGylated enzymes showed much lower activity (1-2 U/gBC). BC swelled membranes are presented herein as a potential support for the preparation of immobilized enzymes for industrial applications, like phenolics polymerization. ; The authors would like to acknowledge Portuguese Foundation for Science and Technology (FCT)under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI01-0145-FEDER-006684) and BioTecNorte operation (NORTE01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. The authors would like also to acknowledge the Basic Science Research Program through the National Research Foundation of Korea (NRF), which was funded by the Ministry of Education (2015R1D1A1A01060747). This work also received funding from the European Union Horizon 2020 research and innovation programme under grant agreement NMP-06-2015-683356 FOLSMART. ...

The bacterial cellulose (BC) secreted by G. xylinus is a network of pure cellulose nanofibers, which has high crystallinity, wettability and mechanical strength. These characteristics make BC an excellent material for tissue engineering constructs, noteworthy for artificial vascular grafts. In this work, the in vivo biocompatibility of BC membranes produced by two G. xylinus strains was analyzed through histological analysis of long-term subcutaneous implants in the mice. The BC implants caused a mild and benign inflammatory reaction that decreased along time and did not elicit a foreign body reaction. A tendency to calcify over time, which may be related to the porosity of the BC implants, was observed, especially amo the less poro s BC-1 implants. In addition, the potential toxicity of BC nanofibers - obtained by chemical-mechanical treatment of BC membranes - subcutaneously implanted in mice was analysed through bone marrow flow cytometry, blood and histological analyses. After 2 and 4 months post implantation, the nanofibers implants were found to accumulate cytoplasmically, in subcutaneous foamy macrophages aggregates. Moreover, no differences were observed between the controls and implanted animals in thymocyte populations and in B lymphocyte precursors and myeloid cells in the bone marrow. ; R. A. N. P. gratefully acknowledges support by the Programme Alssan, the European Union Programme of High Level Scholarships for Latin America (Scholarship No. E07D401931BR). S. M. is recipient of a SFRH/BPD/64726/2009 fellowship from Fundacao para a Ciencia e a Tecnologia (FCT, Portugal). R. M. G. da C. (SFRH/BD/37565/2007) and A. C. (SFRH/BD/31354/2006) are recipients of a PhD fellowship from Fundacao para a Ciencia e a Tecnologia (FCT, Portugal). Funding by FCT and the program COMPETE of the project PTDC/EBB-EBI/112170/2009 is ...

Bacterial cellulose (BC) is an outstanding biomaterial with unique properties, including high water holding capacity, high crystallinity, ultrafine fiber network, high tensile strength in the wet state and the possibility to be shaped into three-dimensional (3D) structures during synthesis. These properties support a wide range of applications, in human and veterinary medicine, odonthology, pharmaceutical industry, acoustic and filter membranes, biotechnological devices and in the food and paper industry. BC is considered biocompatible, presenting an insignificant foreign body reaction; it does not elicit chronic inflammatory responses in vivo. These properties make BC very interesting for tissue engineering applications. Indeed, ongoing research of BC products includes a wide range of biomedical applications: treatment of chronic wounds and burns as temporary coverage, artificial cardiovascular tissues, and guided regeneration of bone, cartilage and nerve. ; The author F.K. Andrade is the recipient of a fellowship from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES, Brazil), and R. A. N. Pértile gratefully acknowledges support by the Programme Alβan, the European Union Programme of High Level Scholarships for Latin America (Scholarship No. E07D401931BR). ...

Bacterial cellulose (BC) has been suggested to be a suitable biomaterial for the development of cardiovascular grafts. The combination of BC with polyvinyl alcohol (PVA) results in nanocomposites with improved properties. Surprisingly, there are very few studies on the BC–blood interaction. This is the focus of this paper. We present the first thorough assessment of the hemocompatibility of the BC/PVA nanocomposite. Whole blood clotting time, plasma recalcification, Factor XII activation, platelet adhesion and activation, hemolytic index and complement activation are all determined. The platelet activation profiles on BC and BC/PVA surfaces are comprehensively characterized. BC and BC/PVA outperformed ePTFE – used as a point of comparison – thus evidencing their suitability for cardiovascular applications. ; Funding for this work was made possible by the FCT fund-ing through the project PTDC/EBB-EBI/112170/2009, FCT PhDgrant (SFRH/BD/66094/2009) and COST-Short Term Mission (COST-STSM-TD1003-8978). Additionally, funding from the Departmentof Industry of the Basque Government program ETORTEK and fromthe Spanish Ministry of Science and Innovation (basic researchgrant CTQ2009-11245 to IR) are also gratefully ...

Nanocomposites of metal nanoparticles (NPs) and bacterial nanocellulose (BC) enable fabrication of soft and biocompatible materials for optical, catalytic, electronic, and biomedical applications. Current BC-NP nanocomposites are typically prepared by in situ synthesis of the NPs or electrostatic adsorption of surface functionalized NPs, which limits possibilities to control and tune NP size, shape, concentration, and surface chemistry and influences the properties and performance of the materials. Here a self-assembly strategy is described for fabrication of complex and well-defined BC-NP composites using colloidal gold and silver NPs of different sizes, shapes, and concentrations. The self-assembly process results in nanocomposites with distinct biophysical and optical properties. In addition to antibacterial materials and materials with excellent senor performance, materials with unique mechanoplasmonic properties are developed. The homogenous incorporation of plasmonic gold NPs in the BC enables extensive modulation of the optical properties by mechanical stimuli. Compression gives rise to near-field coupling between adsorbed NPs, resulting in tunable spectral variations and enhanced broadband absorption that amplify both nonlinear optical and thermoplasmonic effects and enables novel biosensing strategies. ; Funding Agencies|Swedish Foundation for Strategic Research (SFF)Swedish Foundation for Strategic Research [FFL15-0026, RMX18-0039]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; VinnovaVinnova [2016-05156]; Knut and Alice Wallenberg FoundationKnut & Alice Wallenberg Foundation [KAW 2016.0231]; Swedish Research CouncilSwedish Research Council [2017-05178, 2015-05002]; Spanish Ministerio de Ciencia, Innovacion y Universidades (MICINN) [MAT2016-77391-R]; Severo Ochoa Centres of Excellence programme - Spanish Research Agency (AEI) [SEV-2017-0706]

© 2014, Springer Science+Business Media Dordrecht. Structural properties of bacterial cellulose (BC) depend on the microstructure of the material, which in turn is influenced by the bacterial strain. This paper reports the production of BC thin films from two bacterial strains, gluconacetobacter xylinus (GX) and gluconacetobacter europaeus (GE), and three methods of drying the films; at room temperature, freeze drying and supercritical drying. The porosity, transparency, water absorption capacity (WAC) and mechanical properties of the obtained films are further investigated. We conclude that materials with different properties can be fabricated by selecting the bacterial strain or the drying method. Supercritical drying of films of GE achieved mechanically robust and extremely light films, 0.05 g/mL, with up to 96 % of porosity, and with a WAC up 110 times their dried weight. We determined that materials resulting from GE strain are not much affected by the drying method. On the other hand, GX produced BC films more sensitive to the drying method used. Films are denser, 0.6–0.2 g/mL, with tunable porosity from 60 to 90 % and their maximum WAC is 66 times their dried weight. ; The research leading to these results has received funding from the People Program (Marie Curie Actions) of the European Union's Seventh Framework Program (FP7/2007-2013) under REA grant agreement no 303630 and cofounded by the European Social Fund. Authors acknowledge the funding from Spanish Ministry of Economy MAT 2012-35324, from the Generalitat de Catalunya 2014SGR213, COST Action MP1202, Ramon y Cajal grant RYC-2010-06082 (AL), and Chinese Scholarship Council fellowship (MZ). The group of Dr. Alex Peralvarez for their help in the bacterial culture, Dr. Josep PuigMartı´ and the group of Prof. David Amabilino for the use of the optical microscope, Prof. Elies Molins and Toni Pons for the use and training in the use of the freeze drier and Dr. Roberto L. Guzman de Villoria for his advices in the mechanical measurements. ; Peer Reviewed

Abstract In the last decade, bacterial cellulose (BC) has received considerable attention around the world, including in Brazil. The unique properties of BC, such as mechanical stability, tensile strength, thermostability, crystallinity, purity and biocompatibility make it a promising candidate for commercial applications in different areas. This article provides a comprehensive synthesis of commercial applications and studies related to BC around the world and shows the importance and development of Brazilian research during the last decade. In this review we present an overview of BC structure, biosynthesis and possible applications of BC mainly in the food, electronics, bioengineering, cosmetics and biomedical areas. The most significant contributions of Brazilian researchers using BC have been carried out in the biomedical area. Despite the increase in BC reserch, Brazil also needs to develop strategies to expand the use and commercialization of BC products, for which government financial support is extremely necessary.

PURPOSE: To evaluate the biocompatibility and local sensibility reaction to bacterial cellulose hydrogel (0.8%) implanted in subcutaneous tissue of rabbits.METHODS: Fifteen New Zeland rabbits were randomly allocated into three groups: T-1, 7 days, T-2, 21 days, and T-3, 84 days. the new material was implanted in the subcutaneous tissue of the ear; on the scalp over the periosteum; and on the outer and inner surfaces of the thighs, in the aponeurosis of the muscle. At 7, 21 and 84 postoperative days, the material was collected for histological study. the clinical signs, inflammatory response, angiogenesis and fibrogenesis were variables used for analysis of the biocompatibility and biological reactivity to BCH. Analyses were performed with an AXIO (R) Imager. the statistical tests were performed using the GraphPad Prism 5.0 program (R)RESULTS: the intensity of the inflammatory infiltrate, considering the different cell types (PMN, LMN and GC), was statistically significant, with group T1 different from groups T2 and T3 (p = 0.0124 and p < 0.0001, respectively) and T2 different from the T3 group (p = 0.0007). Fibrogenesis grade 1 was the most prevalent in groups T1 (55.4%) and T2 (44.6%). the formation of neovascularization in the group was identified in 84.4% of samples.CONCLUSION: Bacterial cellulose hydrogel (0.8%) is biocompatible, integrating with the subcutaneous tissue of rabbits and inducing tissue remodeling. ; Federal Government (Ministry of Science and Technology, MCT): FINEP (Studies and Projects Financing Agency) ; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) ; Univ Fed Pernambuco, Postgrad Program Surg, BR-50670901 Recife, PE, Brazil ; Univ Fed Pernambuco, Ctr Hlth Sci, Dept Surg, Expt Surg, BR-50670901 Recife, PE, Brazil ; Univ Fed Pernambuco, Ctr Hlth Sci, Dept Pathol, BR-50670901 Recife, PE, Brazil ; Univ Fed Rural Pernambuco, Dept Chem, Expt Stn Sugarcane Carpina, Recife, PE, Brazil ; Fed Univ São Paulo UNIFESP, Dept Surg, Div Plast Surg, São Paulo, Brazil ; Univ Fed Pernambuco, Ctr Ciencias Saude, Dept Cirurgia, BR-50670901 Recife, PE, Brazil ; Fed Univ São Paulo UNIFESP, Dept Surg, Div Plast Surg, São Paulo, Brazil ; Web of Science

Nanocomposites of metal nanoparticles (NPs) and bacterial nanocellulose (BC) enable fabrication of soft and biocompatible materials for optical, catalytic, electronic, and biomedical applications. Current BC–NP nanocomposites are typically prepared by in situ synthesis of the NPs or electrostatic adsorption of surface functionalized NPs, which limits possibilities to control and tune NP size, shape, concentration, and surface chemistry and influences the properties and performance of the materials. Here a self‐assembly strategy is described for fabrication of complex and well‐defined BC–NP composites using colloidal gold and silver NPs of different sizes, shapes, and concentrations. The self‐assembly process results in nanocomposites with distinct biophysical and optical properties. In addition to antibacterial materials and materials with excellent senor performance, materials with unique mechanoplasmonic properties are developed. The homogenous incorporation of plasmonic gold NPs in the BC enables extensive modulation of the optical properties by mechanical stimuli. Compression gives rise to near‐field coupling between adsorbed NPs, resulting in tunable spectral variations and enhanced broadband absorption that amplify both nonlinear optical and thermoplasmonic effects and enables novel biosensing strategies. ; This work was supported by the Swedish Foundation for Strategic Research (SFF) grant no. FFL15‐0026 and framework grant RMX18‐0039 (HEALiX), the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO‐Mat‐LiU no. 2009‐00971), the competence center FunMat‐II that is financially supported by Vinnova (grant no. 2016‐05156), and the Knut and Alice Wallenberg Foundation (grant no. KAW 2016.0231), the Swedish Research Council (grant Nos. 2017‐05178 and 2015‐05002) and the Spanish Ministerio de Ciencia, Innovación y Universidades (MICINN) through the MAT2016‐77391‐R. The ICN2 was supported by the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, grant no. SEV‐2017‐0706). ; Peer reviewed