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Rui L. Reis - One of the best experts on this subject based on the ideXlab platform.
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Differentiation of osteoclast precursors on Gellan gum-based spongy-like hydrogels for bone tissue engineering
Biomedical Materials, 2018Co-Authors: F. Raquel Maia, Rui L. Reis, Joaquim M. Oliveira, David S. Musson, Dorit Naot, Lucília P. Da Silva, Ana Raquel Fernandes Bastos, João B. Costa, Vitor M. Correlo, Jillian CornishAbstract:Bone tissue engineering with cell-scaffold constructs has been attracting a lot of attention, in particular as a tool for the efficient guiding of new tissue formation. However, the majority of the current strategies used to evaluate novel biomaterials focus on osteoblasts and bone formation, while osteoclasts are often overlooked. Consequently, there is limited knowledge on the interaction between osteoclasts and biomaterials. In this study, the ability of spongy-like Gellan gum and hydroxyapatite-reinforced Gellan gum hydrogels to support osteoclastogenesis was investigated in vitro. First, the spongy-like Gellan gum and hydroxyapatite-reinforced Gellan gum hydrogels were characterized in terms of microstructure, water uptake and mechanical properties. Then, bone marrow cells isolated from the long bones of mice and cultured in spongy-like hydrogels were treated with 1,25-dihydroxyvitamin D3 to promote osteoclastogenesis. It was shown that the addition of HAp to spongy-like Gellan gum hydrogels enables the formation of larger pores and thicker walls, promoting an increase in stiffness. Hydroxyapatite-reinforced spongy-like Gellan gum hydrogels support the formation of the aggregates of tartrate-resistant acid phosphatase-stained cells and the expression of genes encoding DC-STAMP and Cathepsin K, suggesting the differentiation of bone marrow cells into pre-osteoclasts. The hydroxyapatite-reinforced spongy-like Gellan gum hydrogels developed in this work show promise for future use in bone tissue scaffolding applications.
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Recent progress in Gellan gum hydrogels provided by functionalization strategies
Journal of Materials Chemistry B, 2016Co-Authors: Ana Helena Dias Bacelar, Joana Silva-correia, Joaquim M. Oliveira, Rui L. ReisAbstract:Gellan gum, a microbial exopolysaccharide fermentation product of Pseudomonas elodea, is a natural biomaterial that has shown promise for tissue engineering and regenerative medicine applications. Although this exopolysaccharide possesses many advantages, such as interesting physicochemical properties and non-cytotoxicity, the mechanical properties and processability of Gellan gum are not totally satisfactory in different tissue engineering contexts, i.e. Gellan gum hydrogels are mechanically weak and the high gelling temperature is also unfavourable. An additional critical limitation is the lack of specific attachment sites for anchorage-dependent cells. However, the multiple hydroxyl groups and the free carboxyl per repeating unit of Gellan gum can be used for chemical modification and functionalization in order to optimize its physicochemical and biological properties. A number of physical modification approaches have also been employed. This review outlines the recent progress in Gellan gum hydrogels and their derivatives, and identifies the new challenges in tissue engineering, provided by blending and/or chemical modification.
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Injectable Gellan gum hydrogels with autologous cells for the treatment of rabbit articular cartilage defects.
Journal of Orthopaedic Research, 2010Co-Authors: João Tiago Oliveira, Leandro S. Gardel, Tommaso Rada, Luís Martins, Manuela E. Gomes, Rui L. ReisAbstract:In this work, the ability of Gellan gum hydrogels coupled with autologous cells to regenerate rabbit full-thickness articular cartilage defects was tested. Five study groups were defined: (a) Gellan gum with encapsulated chondrogenic predifferentiated rabbit adipose stem cells (ASC + GF); (b) Gellan gum with encapsulated nonchondrogenic predifferentiated rabbit adipose stem cells (ASC); (c) Gellan gum with encapsulated rabbit articular chondrocytes (AC) (standard control); (d) Gellan gum alone (control); (e) empty defect (control). Full-thickness articular cartilage defects were created and the Gellan gum constructs were injected and left for 8 weeks. The macroscopic aspect of the explants showed a progressive increase of similarity with the lateral native cartilage, stable integration at the defect site, more pronouncedly in the cell-loaded constructs. Tissue scoring showed that ASC + GF exhibited the best results regarding tissue quality progression. Alcian blue retrieved similar results with a better outcome for the cell-loaded constructs. Regarding real-time PCR analyses, ASC + GF had the best progression with an upregulation of collagen type II and aggrecan, and a downregulation of collagen type I. Gellan gum hydrogels combined with autologous cells constitute a promising approach for the treatment of articular cartilage defects, and adipose derived cells may constitute a valid alternative to currently used articular chondrocytes.
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Gellan gum injectable hydrogels for cartilage tissue engineering applications in vitro studies and preliminary in vivo evaluation
Tissue Engineering Part A, 2010Co-Authors: J T De Oliveira, R. Picciochi, João Filipe Mano, Nuno M. Neves, Luís Martins, Tircia C Santos, Alexandra P Marques, Antonio G Castro, Rui L. ReisAbstract:Gellan gum is a polysaccharide that we have previously proposed for applications in the cartilage tissue engineering field. In this work, Gellan gum hydrogels were tested for their ability to be us...
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Gellan gum: A new biomaterial for cartilage tissue engineering applications
Journal of Biomedical Materials Research Part A, 2009Co-Authors: J T De Oliveira, P B Malafaya, R. Picciochi, João Filipe Mano, L. Martins, Nuno M. Neves, R. A. Sousa, Rui L. ReisAbstract:Gellan gum is a polysaccharide manufactured by microbial fermentation of the Sphingomonas paucimobilis microorganism, being commonly used in the food and pharmaceutical industry. It can be dissolved in water, and when heated and mixed with mono or divalent cations, forms a gel upon lowering the temperature under mild conditions. In this work, Gellan gum hydrogels were analyzed as cells supports in the context of cartilage regeneration. Gellan gum hydrogel discs were characterized in terms of mechanical and structural properties. Transmissionelectron microscopy revealed a quite homogeneous chain arrangement within the hydrogels matrix, and dynamic mechanical analysis allowed to characterize the hydrogels discs viscoelastic properties upon compression solicitation, being the compressive storage and loss modulus of approximately 40 kPa and 3 kPa, respectively, at a frequency of 1 Hz. Rheological measurements determined the sol-gel transition started to occur at approximately 36 degrees C, exhibiting a gelation time of approximately 11 s. Evaluation of the Gellan gum hydrogels biological performance was performed using a standard MTS cytotoxicity test, which showed that the leachables released are not deleterious to the cells and hence were noncytotoxic. Gellan gum hydrogels were afterwards used to encapsulate human nasal chondrocytes (1 x 10(6) cells/mL) and culture them for total periods of 2 weeks. Cells viability was confirmed using confocal calcein AM staining. Histological observations revealed normal chondrocytes morphology and the obtained data supports the claim that this new biomaterial has the potential to serve as a cell support in the field of cartilage regeneration.
Gye-chun Cho - One of the best experts on this subject based on the ideXlab platform.
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Shear strength behavior and parameters of microbial Gellan gum-treated soils: from sand to clay
Acta Geotechnica, 2018Co-Authors: Ilhan Chang, Gye-chun ChoAbstract:Microbial biopolymers have recently been introduced as a new material for soil treatment and improvement. Biopolymers provide significant strengthening to soil, even in small quantities (i.e., at 1/10th or less of the required amount of conventional binders, such as cement). In particular, thermo-gelating biopolymers, including agar gum, Gellan gum, and xanthan gum, are known to strengthen soils noticeably, even under water-saturated conditions. However, an explicitly detailed examination of the microscopic interactions and strengthening characteristics between Gellan gum and soil particles has not yet been performed. In this study, a series of laboratory experiments were performed to evaluate the effect of soil–Gellan gum interactions on the strengthening behavior of Gellan gum-treated soil mixtures (from sand to clay). The experimental results showed that the strengths of sand–clay mixtures were effectively increased by Gellan gum treatment over those of pure sand or clay. The strengthening behavior is attributed to the conglomeration of fine particles as well as to the interconnection of fine and coarse particles, by Gellan gum. Gellan gum treatment significantly improved not only inter-particle cohesion but also the friction angle of clay-containing soils.
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strength durability of Gellan gum biopolymer treated korean sand with cyclic wetting and drying
Construction and Building Materials, 2017Co-Authors: Ilhan Chang, Seokwon Lee, Gye-chun ChoAbstract:Abstract Various biological approaches recently have been explored as alternative environmentally-friendly soil improvement strategies in the fields of construction and geotechnical engineering, with the aim of reducing the use of high greenhouse gas emitting construction binders such as cement. Previous studies have shown the effectiveness of microbial biopolymers in soil improvement. However, there are still concerns about the durability and serviceability of biopolymer treated soils, resulting from the biodegradation and hydrolysis behaviors of the biologically produced compounds. In this study, the strength and durability of Gellan gum biopolymer treated Jumunjin sand (standard sand of the Republic of Korea) was evaluated under cyclic wetting and drying. The results obtained indicate that the cyclic wetting and drying of Gellan gum-treated sands results in a gradual degradation of strength, due to the dissociation of the Gellan gum monomers under wetting and imperfect recomposition during re-drying, with an approximately 30% strength reduction over 10 cycles. However, a certain degree of strength recovery and resistance was observed even after numerous cycles, indicating that Gellan gum-treated soils can potentially be applied for temporary or medium-term purposes in practical construction.
Ashok Pandey - One of the best experts on this subject based on the ideXlab platform.
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statistical approach to optimization of fermentative production of Gellan gum from sphingomonas paucimobilis atcc 31461
Journal of Bioscience and Bioengineering, 2006Co-Authors: Ishwar B. Bajaj, Parag S. Saudagar, Rekha S. Singhal, Ashok PandeyAbstract:Gellan gum, a high-molecular-weight anionic linear polysaccharide produced by pure-culture fermentation from Sphingomonas paucimobilis ATCC 31461, has elicited industrial interest in recent years as a high-viscosity biogum, a suspending agent, a gelling agent, and an agar substitute in microbial media. In this paper we report on the optimization of Gellan gum production using a statistical approach. In the first step, the one factor-at-a-time method was used to investigate the effect of medium constituents such as carbon and nitrogen sources; subsequently, the intuitive analysis based on statistical calculations carried out using the L16 -orthogonal array method. The design for the L16 -orthogonal array was developed and analyzed using MINITAB 13.30 software. All the fermentation runs were carried out at 30+/-2 degrees C on a rotary orbital shaker at 180 rpm for 48 h. In the second step, the effects of amino acids and Gellan precursors such as uridine-5'-diphospate (UDP) and adenosine-5'-diphospate (ADP) on the fermentative production of Gellan gum were studied. Media containing 4% soluble starch, 0.025% yeast extract, 1.0 mM ADP and 0.05% tryptophan gave a maximum yield of 43.6 g l(-1) starch-free Gellan gum, which was significantly higher than reported values in the literature.
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fermentative production of Gellan using sphingomonas paucimobilis
Process Biochemistry, 2003Co-Authors: Madhavan K Nampoothiri, Reeta Rani Singhania, C Sabarinath, Ashok PandeyAbstract:Abstract The biopolymer Gellan belongs to the family of microbial polysaccharides having a wide range of industrial applications. Attempts were made to produce Gellan gum in submerged fermentation (SmF) using Sphingomonas paucimobilis ATCC 31461. Studies on the nutritional requirements for optimal exopolysaccharide production in a salt based synthetic medium revealed soluble starch (20 g/l) as the best carbon source and tryptone (0.5 w/v%) as the best nitrogen source. Supplementation of l -threonine (5 g/l) to the production medium slightly enhanced the formation of Gellan. A maximum of 35.7 g/l Gellan was produced under optimized conditions, which included 20-h old inoculum of 10% (v/v) size. Deacetylated Gellan was also recovered successfully from the fermentation broth.
R M Banik - One of the best experts on this subject based on the ideXlab platform.
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optimization of Gellan gum production by sphingomonas paucimobilis atcc 31461 with nonionic surfactants using central composite design
Journal of Bioscience and Bioengineering, 2008Co-Authors: Santhiagu Arockiasamy, R M BanikAbstract:The effect of nonionic surfactants on Gellan production by Sphingomonas paucimobilis was studied by the addition of 0.5, 0.75, 1.0, 1.25 and 1.5 g/l surfactants to shake flask culture. The nonionic surfactants Tween 80, Tween 40 and Triton X-100 improved Gellan production by S. paucimobilis, and the maximum yield (10.44 g/l) was obtained with Triton X-100 at 0.75 g/l compared with that of the control fermentation (8.63 g/l) without surfactant. The DO profiles associated with Gellan production in a 5-l laboratory fermentor showed higher oxygen and mass transfers during fermentation with surfactant than during control fermentation without surfactant. The addition of surfactant also resulted in a polymer with high viscosity as manifested by its lower acetyl content, than that obtained by control fermentation. A central composite design (CCD) was used to determine the maximum Gellan production at optimum values for three process parameters (Triton X-100 concentration, pH, and temperature) each at five levels in a laboratory fermentor. The maximum Gellan yield (14.62 g/l) was obtained in a 5-l laboratory fermentor with 1.0 g/l Triton X-100 and at pH 6.0 and temperature 29.6°C. Further studies on the effects of agitation and DOT level demonstrated that the surfactants enhanced oxygen transfer resulting in higher Gellan production (27.86 g/l) at higher agitation speed (1000 rpm) and 100% DOT level.
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improvement in production and quality of Gellan gum by sphingomonas paucimobilis under high dissolved oxygen tension levels
Biotechnology Letters, 2006Co-Authors: R M Banik, A SanthiaguAbstract:The effect of agitation rate and dissolved oxygen tension (DOT) on growth and Gellan production by Sphingomonas paucimobilis was studied. Higher cell growth of 5.4 g l−1 was␣obtained at 700 rpm but maximum Gellan (15 g l−1) was produced at 500 rpm. DOT levels above 20% had no effect on cell growth but Gellan yield was increased to 23 g l−1 with increase in DOT level to 100%. Higher DOT levels improved the viscosity and molecular weight of the polymer with change in acetate and glycerate content of the polymer.
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Optimization of nutrients for Gellan gum production by Sphingomonas paucimobilis ATCC-31461 in molasses based medium using response surface methodology.
Bioresource technology, 2006Co-Authors: R M Banik, A Santhiagu, S.n. UpadhyayAbstract:A molasses based medium for the production of Gellan by Sphingomonas paucimobilis ATCC-31461 was developed. Placket-Burman design criterion was applied to study the effect of various nutrient supplements on Gellan production using molasses. Among the 20 variables tested, molasses, tryptone, casaminoacid, disodium hydrogen orthophosphate and manganese chloride showed significant effect on Gellan production. A central composite design was applied to determine the optimum concentrations of the significant variables obtained from Placket-Burman design. Most suitable medium composition for production of Gellan was (g/l): molasses-112.5; tryptone-1; casaminoacid-1; disodium hydrogen orthophosphate-1; manganese chloride-0.947 and the optimum Gellan production was 13.814 g/l.
Marc In Het Panhuis - One of the best experts on this subject based on the ideXlab platform.
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Tissue engineering with Gellan gum
Biomaterials Science, 2016Co-Authors: Leo Stevens, Kerry J. Gilmore, Gordon G. Wallace, Marc In Het PanhuisAbstract:Engineering complex tissues for research and clinical applications relies on high-performance biomaterials that are amenable to biofabrication, maintain mechanical integrity, support specific cell behaviours, and, ultimately, biodegrade. In most cases, complex tissues will need to be fabricated from not one, but many biomaterials, which collectively fulfill these demanding requirements. Gellan gum is an anionic polysaccharide with potential to fill several key roles in engineered tissues, particularly after modification and blending. This review focuses on the present state of research into Gellan gum, from its origins, purification and modification, through processing and biofabrication options, to its performance as a cell scaffold for both soft tissue and load bearing applications. Overall, we find Gellan gum to be a highly versatile backbone material for tissue engineering research, upon which a broad array of form and functionality can be built.
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Modified Gellan gum hydrogels for tissue engineering applications
Soft Matter, 2013Co-Authors: Cameron J. Ferris, Gordon G. Wallace, Kerry J. Gilmore, Marc In Het PanhuisAbstract:Gellan gum is an anionic linear polysaccharide well known for its use as a multi-functional gelling, stabilising and suspending agent in a variety of foods and personal care products. In this Highlight, we explore the recently established directions for Gellan gum hydrogels as materials for applications in tissue engineering. We highlight that modified Gellan gum will be well suited for this purpose, providing that a number of remaining challenges are addressed.
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recovery from applied strain in interpenetrating polymer network hydrogels with ionic and covalent cross links
Soft Matter, 2012Co-Authors: Shannon E Bakarich, Geoffrey C Pidcock, Paul Balding, Leo Stevens, Paul Calvert, Marc In Het PanhuisAbstract:We have prepared an interpenetrating polymer network hydrogel based on the simultaneous formation of two polymer networks, Gellan gum and poly(acrylamide). The Gellan gum network is ionically cross-linked, while poly(acrylamide) network is covalently cross-linked. These gels can recover 53 ± 4% of the hysteresis of the first compressive cycle and 90 ± 9% of subsequent cycles.