Bacterial Cellulose Surface Research Articles

Microstructured Multilevel Bacterial Cellulose Allows the Guided Growth of Neural Stem Cells.

Repeated photolithographic and etching processes allow the production of multileveled polymer microstructures that can be used as templates to produce bacterial cellulose with defined surfaces on demand. By applying this approach, the bacterial cellulose surface obtains new properties and its use for culturing neural stem cells cellulose substrate topography influences the cell growth in a defined manner.

Wet and Dry Forms of Bacterial Cellulose Synthetized by Different Strains of Gluconacetobacter xylinus as Carriers for Yeast Immobilization.

The present study aimed to explore and describe the properties of bacterial cellulose (BC) membranes obtained from three different strains of Gluconacetobacter xylinus for 72, 120, and 168h, used as a carrier support for the immobilization of Saccharomyces cerevisiae. The experiments also included the analysis of glucose consumption and alcohol production during the fermentation process displayed by yeasts immobilized on the BC surface. The results of the present study demonstrate that the number of immobilized yeast cells is dependent on the type of cellulose-synthesizing strain, cellulose form, and duration of its synthesis. The BC in the form of wet membranes obtained after 3days of synthesis displayed the most favorable properties as a carrier for yeast immobilization. The immobilization of yeast cells on BC, regardless of its form, increased the amount of the produced alcohol as compared to free cells. The yeast cells immobilized in BC were able to multiply on its surface during the fermentation process.

Bacterial Cellulose From Rice Waste Water With Addition Chitosan, Glycerol, And Silver Nanoparticle

This study aimed to prepare silver nanoparticles chemically, deposite silver nanoparticles on bacterial cellulose-chitosan-glycerol composite based rice waste water, as well as test the antibacterial activity of bacterial cellulose and its composite. Preparation of silver nanoparticles was conducted by chemical reduction of silver nitrate solution, as well as trisodium citrate as the reductor. Bacterial cellulose from rice waste water is fermented by the bacteria Acetobacter xylinum for 7 days. The dried bacterial cellulose was composited with chitosan and glycerol by immersion method on 2% of chitosan solution and 0.5% of glycerol solution. UV-Vis spectroscopy is used to determine the formation of silvernanoparticles and Particle Size Analyzer to test the size and particle size distribution. Characterization was conducted to bacterial cellulose and its composite included functional groups by FTIR, the mechanical properties by Tensile Tester, crystallinity by XRD, surface photograph by SEM, and antibacterial test against S. aureus and E. coli by the shake flask turbidimetry method. Silver nanoparticle characterization indicated that silver nanoparticles are formed at a wavelength of 421.80 nm, yellow, diameter particle size of 61.8 nm. SEM images showed that the surface of bacterial cellulose had deposited silver nanoparticles and antibacterial test showed an inhibitory effect of bacterial cellulose, bacterial cellulose-chitosan composite, and bacterial cellulose-chitosan-glycerol composite which are deposited silver nanoparticles against the growth of S. aureus and E. coli bacteria.

Preparation of Esterified Bacterial Cellulose for Improved Mechanical Properties and the Microstructure of Isotactic Polypropylene/Bacterial Cellulose Composites.

Bacterial cellulose (BC) has great potential to be used as a new filler to reinforce isotactic polypropylene (iPP) due to its high crystallinity, biodegradability, and efficient mechanical properties. In this study, esterification was used to modify BC, which improved the surface compatibility of the iPP and BC. The results indicated that the cellulose octoate (CO) changed the surface properties from hydrophilic to lipophilic. Compared to the pure iPP, the tensile strength, charpy notched impact strength, and tensile modulus of the iPP/BC composites increased by 9.9%, 7.77%, and 15.64%, respectively. However, the addition of CO reinforced the iPP/CO composites. The tensile strength, charpy notched impact strength, and tensile modulus of the iPP/CO composites increased by 14.23%, 14.08%, and 17.82% compared to the pure iPP. However, the elongation at break of both the composites is decreased. The SEM photographs and particle size distribution of the composites showed improvements when the change of polarity of the BC surface, interface compatibility, and dispersion of iPP improved.

In situ development of nanosilver-impregnated bacterial cellulose for sustainable released antimicrobial wound dressing.

Bacterial cellulose (BC) is an interesting biomaterial found application in various fields due to its novel characteristics like purity, water holding capacity, degree of polymerization and mechanical strength. BC as wound dressing material has limitation because it has no antimicrobial activity. To circumvent this problem, the present study was carried out by impregnation of silver on bacterial cellulose surface. Bacterial cellulose was produced by Gluconoacetobacter hansenii (strain NCIM 2529) by shaking culture method. The sodium borohydride and classical Tollens reaction was used for silver nanoparticle synthesis. The effectiveness of sodium borohydride method compared with Tollens reaction was evaluated on the basis of silver nanoparticle formation and its impregnation on BC as evidenced by UV-Vis spectrum analysis, FE-SEM-EDS analysis and FT-IR spectrum. The potential of nano silver impregnated BC was determined for sustained release antimicrobial wound dressing material by swelling ratio, mechanical properties and antimicrobial activity against Staphylococcus aureus. Thus the nanosilver impregnated bacterial cellulose as promising antimicrobial wound dressing material was evidenced.

Novel Cu@SiO2/bacterial cellulose nanofibers: Preparation and excellent performance in antibacterial activity

The antibacterial composite based on bacterial cellulose (BC) was successfully prepared by in-situ synthesis of SiO2 coated Cu nanoparticles (Cu@SiO2/BC) and its properties were characterized. Its chemical structures and morphologies were evaluated by Fourier transformation infrared spectrum (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results demonstrated that the SiO2 coated Cu particles were well homogeneously precipitated on the surface of BC. The Cu@SiO2/BC was more resistant to oxidation than the Cu nanoparticles impregnated into BC (Cu/BC) and then Cu@SiO2/BC could prolong the antimicrobial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli).

Characterization of hydroxyapatite-coated bio-mimetic bacterial cellulose scaffold for bone tissue regeneration

Event Abstract Back to Event Characterization of hydroxyapatite-coated bio-mimetic bacterial cellulose scaffold for bone tissue regeneration Sung-Jun Ahn1, Sung In Jeong1, Jin-Oh Jeong1, Jong-Seok Park1*, Hui-Jeong Gwon1 and Youn-Mook Lim1 1 Korea Atomic Energy Research Institute, Research Division for Industry and Environment, Korea The goal of this study was to develop novel hydroxyapatite (HA) coated bacterial cellulose (BC) scaffold for bone tissue regeneration. HA coated BC was prepared by immersing in 30 ml of 5X simulated body fluid at 37 ℃ for 12 h. The resulting HA coated BC scaffolds were characterized by scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and thermal gravimetric analysis (TGA). HA spherical globules were newly formed on the surface of BC, fibrous network of BC scaffold still maintained their dimension for cell adhesion and proliferation. ATR-FTIR spectroscopy analysis showed bands assigned to specific signals for phosphate and carbonate ions from HA. HA-coated BC scaffolds of thermal gravimetric analysis presented a residue around 25%. Ability for bone regeneration of HA-coated BC scaffolds were evaluated using the rat calvarial defect model for 4 and 8 weeks. After implantation, both BC and HA-coated BC scaffolds showed new bone formation derived from existing bone, and also found new bone even inside the scaffold. However, new bone area was significantly increased in the HA-coated BC scaffolds that those from BC scaffolds, and bone-like materials were frequently found in HA-coated BC scaffolds. Therefore, the HA-coated BC scaffolds can be used as an effective tool for bone tissue regeneration. Keywords: biomaterial, Biocompatibility, Surface modification, 3D scaffold Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials in constructing tissue substitutes Citation: Ahn S, Jeong S, Jeong J, Park J, Gwon H and Lim Y (2016). Characterization of hydroxyapatite-coated bio-mimetic bacterial cellulose scaffold for bone tissue regeneration. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02129 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. * Correspondence: Dr. Jong-Seok Park, Korea Atomic Energy Research Institute, Research Division for Industry and Environment, Jeongeup, Jeollabuk-do, Korea, Email1 Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Sung-Jun Ahn Sung In Jeong Jin-Oh Jeong Jong-Seok Park Hui-Jeong Gwon Youn-Mook Lim Google Sung-Jun Ahn Sung In Jeong Jin-Oh Jeong Jong-Seok Park Hui-Jeong Gwon Youn-Mook Lim Google Scholar Sung-Jun Ahn Sung In Jeong Jin-Oh Jeong Jong-Seok Park Hui-Jeong Gwon Youn-Mook Lim PubMed Sung-Jun Ahn Sung In Jeong Jin-Oh Jeong Jong-Seok Park Hui-Jeong Gwon Youn-Mook Lim Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Immobilization of gelatin onto acrylic acid grafted bacterial cellulose for regulating cell behaviors using gamma-irradiation

Event Abstract Back to Event Immobilization of gelatin onto acrylic acid grafted bacterial cellulose for regulating cell behaviors using gamma-irradiation Youn-Mook Lim1, Jin-Oh Jeong1*, Sung-Jun Ahn1*, Sung In Jeong1*, Hui-Jeong Gwon1, Jong-Seok Park1 and Jae Young Lee2 1 Korea Atomic Energy Research Institute, Research Division for Industry & Environment, Korea 2 Gwangju Institute of Science and Technology, School of Materials Science & Engineering, Korea Bacterial cellulose(BC) scaffolds are generated from gluconacetobacter hansenii TL-2C. BC has been shown to have a high-burst pressure and ultrafine highly nanofibrous structure similar with that in a natural extracellular matrix (ECM) for tissue engineering. In this study, acrylic acid(AAc) was grafted onto BC surface using gamma-irradiation and then gelatin immobilized it using EDC/NHS reaction. The characterization of the scaffolds was performed by scanning electron microscopy, ATR-FTIR spectroscopy, a toluidine blue O assay, and 2,4,6,-trinitro-benzensulfonic acid assay. The surface morphology of scaffolds was confirmed BC membranes by SEM for gelatin and AAc grafted it, so that it did not change surface morphology. The adhesion and spreading of human mesenchymal stem cells was improved on the gelatin-AAc-BC nanofiber compared to unmodified BC and AAc-BC nanofiber. Therefore, gelatin and AAc grafted BC scaffolds have been possible to tissue scaffold that accelerate the cell behavior for biomedical applications. Keywords: Tissue Engineering, biomaterial, Biocompatibility, 3D scaffold Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomimetic materials Citation: Lim Y, Jeong J, Ahn S, Jeong S, Gwon H, Park J and Lee J (2016). Immobilization of gelatin onto acrylic acid grafted bacterial cellulose for regulating cell behaviors using gamma-irradiation. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.01743 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. * Correspondence: Dr. Jin-Oh Jeong, Korea Atomic Energy Research Institute, Research Division for Industry & Environment, Jeongeup-si, Jeollabuk-do, Korea, nanjinoh@gmail.com Dr. Sung-Jun Ahn, Korea Atomic Energy Research Institute, Research Division for Industry & Environment, Jeongeup-si, Jeollabuk-do, Korea, Email1 Dr. Sung In Jeong, Korea Atomic Energy Research Institute, Research Division for Industry & Environment, Jeongeup-si, Jeollabuk-do, Korea, Email2 Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Youn-Mook Lim Jin-Oh Jeong Sung-Jun Ahn Sung In Jeong Hui-Jeong Gwon Jong-Seok Park Jae Young Lee Google Youn-Mook Lim Jin-Oh Jeong Sung-Jun Ahn Sung In Jeong Hui-Jeong Gwon Jong-Seok Park Jae Young Lee Google Scholar Youn-Mook Lim Jin-Oh Jeong Sung-Jun Ahn Sung In Jeong Hui-Jeong Gwon Jong-Seok Park Jae Young Lee PubMed Youn-Mook Lim Jin-Oh Jeong Sung-Jun Ahn Sung In Jeong Hui-Jeong Gwon Jong-Seok Park Jae Young Lee Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Bacterial Cellulose Supported Gold Nanoparticles with Excellent Catalytic Properties

Amidoxime surface functionalized bacterial cellulose (AOBC) has been successfully prepared by a simple two-step method without obviously changing the morphology of bacterial cellulose. AOBC has been used as the reducing agent and carrier for the synthesis of gold nanoparticles (AuNPs) that distributed homogeneously on bacterial cellulose surface. Higher content in amidoxime groups in AOBC is beneficial for the synthesis of AuNPs with smaller and more uniform size. The AuNPs/AOBC nanohybrids have excellent catalytic activity for reduction of 4-nitrophenol (4-NP) by using NaBH4. It was found that catalytic activity of AuNPs/AOBC first increases with increasing NaBH4 concentration and temperature, and then leveled off at NaBH4 concentration above 238 mM and temperature above 50 °C. Moreover, AuNPs with smaller size have higher catalytic activity. The highest apparent turnover frequency of AuNPs/AOBC is 1190 h(-1). The high catalytic activity is due to the high affinity of 4-NP with AuNPs/AOBC and the reduced product 4-aminophenol has good solubility in water in the presence of AuNPs/AOBC. The catalytic stability of the AuNPs/AOBC was estimated by filling a fluid column contained AuNPs/AOBC and used for continuously catalysis of the reduction of 4-NP by using NaBH4. The column works well without detection of 4-NP in the eluent after running for more than two months, and it is still running. This work provides an excellent catalyst based on bacterial cellulose stabilized AuNPs and has promising applications in industry.

Physicochemical characterization of gelatin-immobilized, acrylic acid-bacterial cellulose nanofibers as cell scaffolds using gamma-irradiation

Bacterial cellulose (BC) has been shown to have a high-burst pressure, high-water contact, and ultrafine highly nanofibrous structure similar with that in a natural extracellular matrix (ECM). In the present study, we developed a BC-based functional scaffold for tissue engineering using radiation technology. BC was generated by Gluconacetobacter hansenii TL-2C. Acrylic acid (AAc) was grafted onto BC surfaces under aqueous conditions using gamma-ray irradiation. The characterization of the scaffold was performed by scanning electron microscopy, ATR-FTIR spectroscopy, a toluidine blue O assay, and 2,4,6,-trinitro-benzensulfonic acid assay. AAc was grafted on the BC under gamma-ray irradiation. Gelatin was chemically conjugated on the AAc-BC scaffolds through EDC chemistry. The morphology of the modified BC nanofibers did not change, while representative features of AAc and gelatin were maintained. The adhesion and spreading of human mesenchymal stem cells was improved on the gelatin-AAc-BC nanofibers compared to unmodified BC and AAc-BC nanofibers. Our results suggest that gelatin-immobilized BC nanofiber scaffolds can be a promising way to fabricate three-dimentional, nanofibrous scaffolds that accelerate cell behavior for biomedical applications.

Nitrogen-Doped Carbon Nanofiber/Molybdenum Disulfide Nanocomposites Derived from Bacterial Cellulose for High-Efficiency Electrocatalytic Hydrogen Evolution Reaction.

To remit energy crisis and environmental deterioration, non-noble metal nanocomposites have attracted extensive attention, acting as a fresh kind of cost-effective electrocatalysts for hydrogen evolution reaction (HER). In this work, hierarchically organized nitrogen-doped carbon nanofiber/molybdenum disulfide (pBC-N/MoS2) nanocomposites were successfully prepared via the combination of in situ polymerization, high-temperature carbonization process, and hydrothermal reaction. Attributing to the uniform coating of polyaniline on the surface of bacterial cellulose, the nitrogen-doped carbon nanofiber network acts as an excellent three-dimensional template for hydrothermal growth of MoS2 nanosheets. The obtained hierarchical pBC-N/MoS2 nanocomposites exhibit excellent electrocatalytic activity for HER with small overpotential of 108 mV, high current density of 8.7 mA cm(-2) at η = 200 mV, low Tafel slope of 61 mV dec(-1), and even excellent stability. The greatly improved performance is benefiting from the highly exposed active edge sites of MoS2 nanosheets, the intimate connection between MoS2 nanosheets and the highly conductive nitrogen-doped carbon nanofibers and the three-dimensional networks thus formed. Therefore, this work provides a novel strategy for design and application of bacterial cellulose and MoS2-based nanocomposites as cost-effective HER eletrocatalysts.

Production of hydroxyapatite–bacterial cellulose nanocomposites from agroindustrial wastes

In the present work, bionanocomposites based on bacterial cellulose (BC) obtained from alternative sources (cashew juice and sisal liquid waste) and hydroxyapatite (HA) were developed. BC–HA composites were prepared through alternate immersion in CaCl2 and Na2HPO4 solutions. Cellulose was successfully produced from the alternative sources of media without the need for additional supplementation and HA crystals that homogeneously precipitated onto the BC surface. The Ca/P ratio ranged from 1.53 to 1.58, indicating the presence of calcium-deficient HA in the composites; this is a phase similar to biological apatite. After immersion into synthetic body fluid, the HA layer formed on the surface of pure BC and the composites, attesting the material’s bioactivity. Moreover, apatite deposition on the composites was up to three times higher than observed on pure cellulose with no significant desorption of apatite from the composites. These results support that the BC derived from agroindustrial wastes have potential to produce nanocomposites of cellulose/HA for use in bone tissue regeneration.

Immobilization of lecithin on bacterial cellulose nanofibers for improved biological functions

In an attempt to improve the biological behavior of pristine bacterial cellulose (BC), lecithin (LEC) has been immobilized on the surface of BC nanofibers by solution immersion and subsequent chemical crosslinking with proanthocyanidin (PA). The as-prepared LEC-immobilized BCs (denoted as BC/LECs) were characterized by SEM, FTIR, and XRD, and their dynamic mechanical properties, thermal stability, and hydrophilicity were assessed. The presence of LEC on BC surface was confirmed by SEM and FTIR analyses. It has been found that BC/LECs retain the three-dimensional (3D) porous network structure of pristine BC. The BC/LECs still demonstrate favorable mechanical properties, surface hydrophilicity, and thermal stability. More importantly, preliminary cell studies suggest that the BC/LECs show improved cell behavior over pristine BC.

Optimization of Cell Growth on Bacterial Cellulose by Adsorption of Collagen and Poly-L-Lysine

Poly-L-lysine and collagen were separately added to bacterial cellulose (BC) nanofibers. The ionic surface charge had been previously modified in order to promote the adsorption of poly-L-lysine and collagen. Cell adhesion of Chinese hamster ovary (CHO) cells on BC surfaces was confirmed by removing unattached cells from the BC substrates. Cell viability was calculated and it was determined that both poly-L-lysine-BC and collagen-BC substrates are viable for cell growth. The results showed that the cell viability in poly-L-lysine modified BC substrate is similar to the one observed in polystyrene tissue culture plates.

Flexible conductive polypyrrole nanocomposite membranes based on bacterial cellulose with amphiphobicity

Flexible conductive polypyrrole nanocomposite membranes based on bacterial cellulose (BC) with amphiphobicity have been successfully prepared through in situ chemical synthesis and then infiltrated with polysiloxane solution. The results suggested that polypyrrole (PPy) nanoparticles deposited on the surface of BC formed a continuous core–shell structure by taking along the BC template. After modification with polysiloxane, the surface characteristics of the conductive BC membranes changed from highly hydrophilic to hydrophobic. The AFM images revealed that the roughness of samples after polysiloxane treatment increased along with the increase of pyrrole concentration. The contact angles (CAs) data revealed that the highest water contact angle and highest oil contact angle are 160.3° and 136.7°, respectively. The conductivity of the amphiphobic membranes with excellent flexibility reached 0.32S/cm and demonstrated a good electromagnetic shielding effectiveness with an SE of 15dB which could be applied in electromagnetic shielding materials with self-cleaning properties. It opened a new field of potential applications of BC materials.

β2 integrins (CD11/18) are essential for the chemosensory adhesion and migration of polymorphonuclear leukocytes on bacterial cellulose.

Bacterial cellulose (BC) has been studied widely for applications in biomedical materials such as prosthetic artificial blood vessels owing to its unique characteristics, which include nontoxicity and nonimmunogenicity as compared with synthetic biopolymers such as expanded polytetrafluorethylene (ePTFE). However, to date, studies on the relative effect of leukocytes on BC as a prosthetic vascular graft are insufficient. Polymorphonuclear leukocytes (PMN) play a pivotal role in early-phase immune response to bacterial or periprosthetic infection. PMN recruitment at sites of infection or inflammation mediated by various integrins such as β2 integrin family (CD11/CD18 family). Therefore, we discuss our investigations into the mechanisms by which β2 integrins-mediated chemosensory adhesion and migration of PMN on the vascular graft surface, BC. Our results show that CD11b/CD18 components mainly mediate PMN adherence on BC. CD11b/CD18 displays weak coordination with the other two α subunits (CD11a and CD11c). Furthermore, it was found that the β subunit (CD18) plays a critical role in both the adhesion and migration of N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated PMN on BC. The activity of CD18 contrasts with that of the individual α subunits. Among these, only CD11b displayed inhibition of PMN migration on BC surfaces.

MWCNTs-like protection layer formation on bacterial cellulose bundles as a potential material for suspended resonator.

Suspended carbon naotubes (CNTs) resonator is a sensitive detector for chemical and biological applications. Small sizes of CNTs can enhance sensitivity, but increase complexity for fabrication. In order to overcome the challenges, a novel technique has been developed to produce a long, sensitive and high tensile strength carbon nanotubes (CNT) coated bacterial cellulose (BC) bundle. This study demonstrates the use of ultrasonication to perform carboxyl functionalized multi-walled carbon nanotubes (MWCNTs-COOH) self-assembling on the surface of BC bundles (BC/MWCNTs) via hydrogen bonds. Ultrasonication can disrupt dense cellulose network and produce the long BC/MWCNTs bundles ranging from 30 to 100 μm. Raman spectroscopy shows a drop at peak of hydroxyl (-OH, 3700 m(-1)) and carbonyl (C=O, 1600 cm(-1)). This indicates the formation of the continuous MWCNTs-like protection layer on BC surface. Electrical properties of the BC/MWCNTs bundles showed linearity from -6 V to +6 V. Composites with BC treated by higher ultrasonic powers, 100 W, show higher conductivity comparing to 80 W. Sensitivity from 10(-7) to 10(-9) A of long BC/MWCNTs composite bundles is reported in this paper. This technique may be competitive to the current state of carbon nanotubes resonator.

감마선 조사에 의한 헤파린이 도입된 박테리아 셀룰로오스의 골조 직공학용 지지체로서의 개발 및 특성분석

Bacterial cellulose(BC) scaffolds are generated from gel by gluconacetobacter hansenii TL-2C. BC has good properties such as high-burst pressure and the ultrafine highly nanofibrous structure of mimic natural extra celluar matrix(ECM) for tissue engineering. In this study, 2-aminoethyl methacrylate(AEMA) was grafted onto BC surface using gamma-irradiation and then heparin immobilized it using EDC/NHS reaction. The surface morphology of scaffolds were confirmed BC membranes by SEM for heparin and AEMA grafted it, so that it was not changed surface morphology. The result of TBO, fluorescamine staining, ATR-FTIR confirmed that heparin and AEMA immobilized it. Also result of in vitro test, heparin immobilized AEMA-BC proliferation of hMSC to higher than unmodified BC by CCK-8 and ALP activity then heparin immobilized AEMA-BC cumulative of BMP-2 was confirmed decrease by release test. Therefore, heparin and AEMA grafted BC scaffolds have been possible to tissue scaffold in bone tissue engineering.

Bacterial cellulose-reinforced hydroxyapatite functionalized graphene oxide: a potential osteoinductive composite

Bacterial cellulose (BC) is a nanofibrous biocompatible scaffold used in bone tissue engineering. Graphene oxide/hydroxyapatite (GOHA) composite supports the adhesion of osteoblast cells with good viability. In the present study, GOHA was prepared by the wet chemical precipitation method, and BC obtained from Acetobacter aceti was added to the aqueous suspension of GOHA to prepare GOHABC. The scanning electron microscopic image of GOHABC showed uniform adsorption of GOHA on the surface of BC. The osteoinductive potential of the GOHABC scaffold was analyzed by alkaline phosphatase (ALP) activity assay using MG-63 cells, and its biocompatibility nature was studied by using both MG-63 and NIH-3T3 cells. The ALP activity and biocompatibility studies showed that GOHABC is a potential osteoinductive material in vitro and may be tried in the future for in vivo studies.

Surface characterization of TEMPO‐oxidized bacterial cellulose

In this study, we focused on the surface character of bacterial cellulose (BC) before and after oxidation mediated by 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO).Solid‐state 13C NMR, XPS, SEM, contact angle and surface free energy analyses were performed to investigate the effects of various parameters (reaction time and oxidant and catalyst concentrations) on the surface composition, morphology and polarity of the BC. The results provided by the combined use of these techniques showed that hydrogen bonds were disrupted on the BC surface after carboxylation occurred; therefore, the surface of oxidized BC was rougher than that of the original BC, and the surface free energy, especially the polar components, increased after oxidation. Copyright © 2013 John Wiley & Sons, Ltd.