Mechanical Analysis of Bacterial Nanocellulose for Biomedical Applications

2012 ◽  
Author(s):  
Joseph M. Schwertz ◽  
Paul Gatenholm ◽  
Alan W. Eberhardt
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Chemical Structure ◽  
Mechanical Analysis ◽  
Gluconacetobacter Xylinus ◽  
Bacterial Nanocellulose

Bacterial nanocellulose (BNC) is a biopolymer that has been used in a variety of applications ranging from speaker diaphragms to biomedical products. With the exact chemical structure as that produced by plants, BNC is created by microbes like Gluconacetobacter xylinus. One of the unique aspects of BNC is its ability to have a wide variety of mechanical properties while in hydrogel form.

Structure, Microstructure, and Selected Mechanical Properties of Ti-Zr-Mo Alloys for Biomedical Applications

2014 ◽  
Vol 922 ◽  
pp. 75-80 ◽  
Author(s):  
Diego Rafael Nespeque Correa ◽  
Pedro Akira Bazaglia Kuroda ◽  
Carlos Roberto Grandini
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Young's Modulus ◽  
Microstructural Analysis ◽  
Melting Furnace ◽  
High Hardness ◽  
Mechanical Analysis ◽  
Β Phase

New titanium alloys for biomedical applications have been developed primarily with the addition of Nb, Ta, Mo, and Zr, because those elements stabilize the β phase and they don’t cause cytotoxicity in the organism. The objective of this paper is to analyze the effect of molybdenum on the structure, microstructure, and selected mechanical properties of Ti-15Zr-xMo (x = 5, 10, 15, and 20 wt%) alloys. The samples were produced in an arc-melting furnace with inert argon atmosphere, and they were hot-rolled and homogenized. The samples were characterized using chemical, structural, and microstructural analysis. The mechanical analysis was made using Vickers microhardness and Young’s modulus measurements. The compositions of the alloys were sensitive to the molybdenum concentration, indicating the presence of α’+α”+β phases in the Ti-15Zr-5Mo alloy, α”+β in the Ti-15Zr-10Mo alloy, and β phase in the Ti-15Zr-15Mo and Ti-15Zr-20Mo alloys. The mechanical properties showed favorable values for biomedical application in the alloys presenting high hardness and low Young’s modulus compared with CP-Ti.

scholarly journals The Role of Two-Step Blending in the Properties of Starch/Chitin/Polylactic Acid Biodegradable Composites for Biomedical Applications

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 592 ◽  
Author(s):  
Niyi Gideon Olaiya ◽  
Arif Nuryawan ◽  
Peter Kayode Oke ◽  
H. P. S. Abdul Khalil ◽  
Samsul Rizal ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polylactic Acid ◽  
Biomedical Applications ◽  
Loss Modulus ◽  
Starch Content ◽  
Mechanical Analysis ◽  
Research Trend ◽  
Toxicity Tests ◽  
Distinct Peak ◽  
Peak Value

The current research trend for excellent miscibility in polymer mixing is the use of plasticizers. The use of most plasticizers usually has some negative effects on the mechanical properties of the resulting composite and can sometimes make it toxic, which makes such polymers unsuitable for biomedical applications. This research focuses on the improvement of the miscibility of polymer composites using two-step mixing with a rheomixer and a mix extruder. Polylactic acid (PLA), chitin, and starch were produced after two-step mixing, using a compression molding method with decreasing composition variation (between 8% to 2%) of chitin and increasing starch content. A dynamic mechanical analysis (DMA) was used to study the mechanical behavior of the composite at various temperatures. The tensile strength, yield, elastic modulus, impact, morphology, and compatibility properties were also studied. The DMA results showed a glass transition temperature range of 50 °C to 100 °C for all samples, with a distinct peak value for the loss modulus and factor. The single distinct peak value meant the polymer blend was compatible. The storage and loss modulus increased with an increase in blending, while the loss factor decreased, indicating excellent compatibility and miscibility of the composite components. The mechanical properties of the samples improved compared to neat PLA. Small voids and immiscibility were noticed in the scanning electron microscopy images, and this was corroborated by X-ray diffraction graphs that showed an improvement in the crystalline nature of PLA with starch. Bioabsorption and toxicity tests showed compatibility with the rat system, which is similar to the human system.

scholarly journals Effect of Glass Fibers Thermal Treatment on the Mechanical and Thermal Behavior of Polysulfone Based Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 902 ◽  
Author(s):  
Galal Sherif ◽  
Dilyus I. Chukov ◽  
Victor V. Tcherdyntsev ◽  
Valerii G. Torokhov ◽  
Dmitry D. Zherebtsov
Keyword(s):  
Mechanical Properties ◽  
Thermal Treatment ◽  
Interfacial Adhesion ◽  
Chemical Structure ◽  
Glass Fibers ◽  
Mechanical Analysis ◽  
Shear Tests ◽  
Sem Images ◽  
Polymer Ratio ◽  
Properties Of Composites

The effect of thermal treatment of glass fibers (GF) on the mechanical and thermo-mechanical properties of polysulfone (PSU) based composites reinforced with GF was investigated. Flexural and shear tests were used to study the composites’ mechanical properties. A dynamic mechanical analysis (DMA) and a heat deflection temperature (HDT) test were used to study the thermo-mechanical properties of composites. The chemical structure of the composites was studied using IR-spectroscopy, and scanning electron microscopy (SEM) was used to illustrate the microstructure of the fracture surface. Three fiber to polymer ratios of initial and preheated GF composites (50/50, 60/40, 70/30 (wt.%)) were studied. The results showed that the mechanical and thermo-mechanical properties improved with an increase in the fiber to polymer ratio. The interfacial adhesion in the preheated composites enhanced as a result of removing the sizing coating during the thermal treatment of GF, which improved the properties of the preheated composites compared with the composites reinforced with initial untreated fibers. The SEM images showed a good distribution of the polymer on the GF surface in the preheated GF composites.

scholarly journals Bacterial Nanocellulose-Enhanced Alginate Double-Network Hydrogels Cross-Linked with Six Metal Cations for Antibacterial Wound Dressing

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2683
Author(s):  
Mina Shahriari-Khalaji ◽  
Siyi Hong ◽  
Gaoquan Hu ◽  
Ying Ji ◽  
Feng F. Hong
Keyword(s):  
Mechanical Properties ◽  
Antibacterial Activity ◽  
Wound Dressing ◽  
Biomedical Applications ◽  
Antibacterial Activities ◽  
Ph Responsive ◽  
Time Saving ◽  
Bacterial Nanocellulose ◽  
Vacuum Suction ◽  
Copper Zinc

Alginate (Alg) and bacterial nanocellulose (BNC) have exhibited great potential in biomedical applications, especially wound dressing. Non-toxicity and a moisture-maintaining nature are common features making them favorable for functional dressing fabrication. BNC is a natural biopolymer that promotes major advances to the current and future biomedical materials, especially in a flat or tubular membrane form with excellent mechanical strength at hydrated state. The main drawback limiting wide applications of both BNC and Alg is the lack of antibacterial activity, furthermore, the inherent poor mechanical property of Alg leads to the requirement of a secondary dressing in clinical treatment. To fabricate composite dressings with antibacterial activity and better mechanical properties, sodium alginate was efficiently incorporated into the BNC matrix using a time-saving vacuum suction method followed by cross-linking through immersion in separate solutions of six cations (manganese, cobalt, copper, zinc, silver, and cerium). The results showed the fabricated composites had not only pH-responsive antibacterial activities but also improved mechanical properties, which are capable of acting as smart dressings. All composites showed non-toxicity toward fibroblast cells. Rat model evaluation showed the skin wounds covered by the dressings healed faster than by BNC.

Bacterial Nanocellulose as a Renewable Material for Biomedical Applications

MRS Bulletin ◽  
2010 ◽  
Vol 35 (3) ◽  
pp. 208-213 ◽  
Author(s):  
Paul Gatenholm ◽  
Dieter Klemm
Keyword(s):  
Tissue Regeneration ◽  
Biomedical Applications ◽  
Foreign Body Reaction ◽  
Cell Immobilization ◽  
Gluconacetobacter Xylinus ◽  
Bacterial Nanocellulose ◽  
Renewable Material ◽  
Biomedical Field ◽  
Water Holding ◽  
Cell Support

AbstractNanocellulose, such as that produced by the bacteria Gluconacetobacter xylinus (bacterial cellulose, BC), is an emerging biomaterial with great potential as a biological implant, wound and burn dressing material, and scaffolds for tissue regeneration. BC has remarkable mechanical properties despite the fact that it contains up to 99% water. The water-holding ability is the most probable reason why BC implants do not elicit any foreign body reaction. Moreover, the nanostructure and morphological similarities with collagen make BC attractive for cell immobilization and cell support. The architecture of BC materials can be engineered over length scales ranging from nano to macro by controlling the biofabrication process. This article describes current and future applications of BC in the biomedical field.

scholarly journals Smart hydrogels based on itaconic acid for biomedical application

2009 ◽  
Vol 63 (6) ◽  
pp. 603-610
Author(s):  
Simonida Tomic ◽  
Maja Micic ◽  
Bojana Krezovic ◽  
Sava Dobic ◽  
Edin Suljovrujic ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Itaconic Acid ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
In Vitro Study ◽  
Mechanical Analysis ◽  
Wound Dressings ◽  
Temperature Sensitive ◽  
Stimuli Responsive

pH and temperature sensitive hydrogels, based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) copolymers, were prepared by gamma irradiation and characterized in order to examine their potential use in biomedical applications. The influence of comonomer ratio in these smart copolymers on their morphology, mechanical properties, biocompatibility and microbe penetration capability was investigated. The mechanical properties of copolymers were investigated using the dynamic mechanical analysis (DMA), while their morphology was examined by scanning electron microscopy (SEM). The morphology and mechanical properties of these hydrogels were found to be suitable for most requirements of biomedical applications. The in vitro study of P(HEMA/IA) biocompatibility showed no evidence of cell toxicity nor any considerable hemolytic activity. Furthermore, the microbe penetration test showed that neither Staphylococcus aureus nor Escherichia coli passed through the hydogel dressing; thus the P(HEMA/IA) dressing could be considered a good barrier against microbes. All results indicate that stimuli-responsive P(HEMA/IA) hydrogels have great potential for biomedical applications, especially for skin treatment and wound dressings.

scholarly journals Highly Tough, Biocompatible, and Magneto-Responsive Fe3O4/Laponite/PDMAAm Nanocomposite Hydrogels

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jin Hyun Lee ◽  
Wen Jiao Han ◽  
Hyo Seon Jang ◽  
Hyoung Jin Choi
Keyword(s):  
Mechanical Properties ◽  
Biomedical Applications ◽  
Chemical Structure ◽  
Tensile Tests ◽  
Thermal And Mechanical Properties ◽  
Soft Actuator ◽  
Nanocomposite Hydrogels ◽  
Good Biocompatibility ◽  
Responsive Hydrogels

Abstract Magneto-responsive hydrogels (MRHs) have attracted considerable attention in various applications owing to their smart response to an externally applied magnetic field. However, their practical uses in biomedical fields are limited by their weak mechanical properties and possible toxicity to the human body. In this study, tough, biocompatible, and magneto-responsive nanocomposite hydrogels (MR_NCHs) were developed by the in-situ free-radical polymerization of N, N-dimethylacrylamide (DMAAm) and laponite and Fe3O4 nanoparticles. The effects of the concentrations of DMAAm, water, and laponite and Fe3O4 nanoparticles in the pre-gel solutions or mixtures on the viscoelastic and mechanical properties of the corresponding hydrogels were examined by performing rheological and tensile tests, through which the mixture composition producing the best MR_NCH system was optimized. The effects were also explained by the possible network structures of the MR_NCHs. Moreover, the morphology, chemical structure, and thermal and mechanical properties of the MR_NCHs were analyzed, while comparing with those of the poly(DMAAm) (PDMAAm) hydrogels and laponite/PDMAAm NCHs. The obtained optimal MR_NCH exhibited noticeable magnetorheological (MR) behavior, excellent mechanical properties, and good biocompatibility. This study demonstrates how to optimize the best Fe3O4/laponite/PDMAAm MR_NCH system and its potential as a soft actuator for the pharmaceutical and biomedical applications.

scholarly journals Engineering bioactive synthetic polymers for biomedical applications: A review with emphasis on tissue engineering and controlled release

2021 ◽  
Author(s):  
Edna Johana Bolívar-Monsalve ◽  
Mario Moises Álvarez ◽  
Samira Hosseini ◽  
Michelle Alejandra Espinosa-Hernandez ◽  
Carlos Fernando Ceballos-González ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Controlled Release ◽  
Biomedical Engineering ◽  
Biomedical Applications ◽  
Chemical Structure ◽  
Synthetic Polymers

Synthetic polymers (SyPs) have found many relevant applications niches in biomedical engineering. Their mechanical properties, defined chemical structure, batch to batch consistency are attractive features that render them superior (at...

Cellulose Nanofibrils-based Hydrogels for Biomedical Applications: Progresses and Challenges

2020 ◽  
Vol 27 (28) ◽  
pp. 4622-4646 ◽  
Author(s):  
Huayu Liu ◽  
Kun Liu ◽  
Xiao Han ◽  
Hongxiang Xie ◽  
Chuanling Si ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metal Ion ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Cellulose Nanofibrils ◽  
Wound Dressings ◽  
Preparation Methods ◽  
Tissue Scaffold ◽  
Surface Areas ◽  
Mechanical Methods

Background: Cellulose Nanofibrils (CNFs) are natural nanomaterials with nanometer dimensions. Compared with ordinary cellulose, CNFs own good mechanical properties, large specific surface areas, high Young's modulus, strong hydrophilicity and other distinguishing characteristics, which make them widely used in many fields. This review aims to introduce the preparation of CNFs-based hydrogels and their recent biomedical application advances. Methods: By searching the recent literatures, we have summarized the preparation methods of CNFs, including mechanical methods and chemical mechanical methods, and also introduced the fabrication methods of CNFs-based hydrogels, including CNFs cross-linked with metal ion and with polymers. In addition, we have summarized the biomedical applications of CNFs-based hydrogels, including scaffold materials and wound dressings. Results: CNFs-based hydrogels are new types of materials that are non-toxic and display a certain mechanical strength. In the tissue scaffold application, they can provide a micro-environment for the damaged tissue to repair and regenerate it. In wound dressing applications, it can fit the wound surface and protect the wound from the external environment, thereby effectively promoting the healing of skin tissue. Conclusion: By summarizing the preparation and application of CNFs-based hydrogels, we have analyzed and forecasted their development trends. At present, the research of CNFs-based hydrogels is still in the laboratory stage. It needs further exploration to be applied in practice. The development of medical hydrogels with high mechanical properties and biocompatibility still poses significant challenges.

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