Bacterial cellulose (BC) is a unique and promising material for use as implants and scaffolds in tissue engineering. It is composed of a pure cellulose nanofiber mesh spun by bacteria. It is ...remarkable for its strength and its ability to be engineered structurally and chemically at nano-, micro-, and macroscales. Its high water content and purity make the material biocompatible for multiple medical applications. Its biocompatibility, mechanical strength, chemical and morphologic controllability make it a natural choice for use in the body in biomedical devices with broader application than has yet been utilized. This paper reviews the current state of understanding of bacterial cellulose, known methods for controlling its physical and chemical structure (e.g., porosity, fiber alignment, etc.), biomedical applications for which it is currently being used, or investigated for use, challenges yet to be overcome, and future possibilities for BC.
Celotno besedilo
Dostopno za:
CEKLJ, DOBA, EMUNI, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK
The first book dedicated to the potential applications and unique properties of bacterial cellulose (BC), this seminal work covers the basic science, technology, and economic impact of this bulk ...chemical as well as the companies and patents that are driving the field. It reviews the biosynthesis and properties of BC, including genetics and characterization; discusses the advancing technology as it relates to product development, bioreactors, and production; and analyzes the economic impact of BC on a diverse range of industry applications, including materials and biomaterials, biological and polymer sciences, and electromechanical engineering.
Cartilage lesions can progress into secondary osteoarthritis and cause severe clinical problems in numerous patients. As a prospective treatment of such lesions, human-derived induced pluripotent ...stem cells (iPSCs) were shown to be 3D bioprinted into cartilage mimics using a nanofibrillated cellulose (NFC) composite bioink when co-printed with irradiated human chondrocytes. Two bioinks were investigated: NFC with alginate (NFC/A) or hyaluronic acid (NFC/HA). Low proliferation and phenotypic changes away from pluripotency were seen in the case of NFC/HA. However, in the case of the 3D-bioprinted NFC/A (60/40, dry weight % ratio) constructs, pluripotency was initially maintained, and after five weeks, hyaline-like cartilaginous tissue with collagen type II expression and lacking tumorigenic Oct4 expression was observed in 3D -bioprinted NFC/A (60/40, dry weight % relation) constructs. Moreover, a marked increase in cell number within the cartilaginous tissue was detected by 2-photon fluorescence microscopy, indicating the importance of high cell densities in the pursuit of achieving good survival after printing. We conclude that NFC/A bioink is suitable for bioprinting iPSCs to support cartilage production in co-cultures with irradiated chondrocytes.
Cartilage repair and replacement is a major challenge in plastic reconstructive surgery. The development of a process capable of creating a patient-specific cartilage framework would be a major ...breakthrough. Here, we described methods for creating human cartilage in vivo and quantitatively assessing the proliferative capacity and cartilage-formation ability in mono- and co-cultures of human chondrocytes and human mesenchymal stem cells in a three-dimensional (3D)-bioprinted hydrogel scaffold. The 3D-bioprinted constructs (5 × 5 × 1.2 mm) were produced using nanofibrillated cellulose and alginate in combination with human chondrocytes and human mesenchymal stem cells using a 3D-extrusion bioprinter. Immediately following bioprinting, the constructs were implanted subcutaneously on the back of 48 nude mice and explanted after 30 and 60 days, respectively, for morphological and immunohistochemical examination. During explantation, the constructs were easy to handle, and the majority had retained their macroscopic grid appearance. Constructs consisting of human nasal chondrocytes showed good proliferation ability, with 17.2% of the surface areas covered with proliferating chondrocytes after 60 days. In constructs comprising a mixture of chondrocytes and stem cells, an additional proliferative effect was observed involving chondrocyte production of glycosaminoglycans and type 2 collagen. This clinically highly relevant study revealed 3D bioprinting as a promising technology for the creation of human cartilage.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This study presents a novel, green, and efficient way of preparing crosslinked aerogels from cellulose nanofibers (CNFs) and alginate using non‐covalent chemistry. This new process can ultimately ...facilitate the fast, continuous, and large‐scale production of porous, light‐weight materials as it does not require freeze‐drying, supercritical CO2 drying, or any environmentally harmful crosslinking chemistries. The reported preparation procedure relies solely on the successive freezing, solvent‐exchange, and ambient drying of composite CNF‐alginate gels. The presented findings suggest that a highly‐porous structure can be preserved throughout the process by simply controlling the ionic strength of the gel. Aerogels with tunable densities (23–38 kg m−3) and compressive moduli (97–275 kPa) can be prepared by using different CNF concentrations. These low‐density networks have a unique combination of formability (using molding or 3D‐printing) and wet‐stability (when ion exchanged to calcium ions). To demonstrate their use in advanced wet applications, the printed aerogels are functionalized with very high loadings of conducting poly(3,4‐ethylenedioxythiophene):tosylate (PEDOT:TOS) polymer by using a novel in situ polymerization approach. In‐depth material characterization reveals that these aerogels have the potential to be used in not only energy storage applications (specific capacitance of 78 F g−1), but also as mechanical‐strain and humidity sensors.
This study presents a novel, fast, and green way of preparing cross‐linked, ambient‐dried aerogels made from cellulose nanofibers and alginate. It further demonstrates the preparation of 3D‐printed aerogels with tailorable shapes, structures, and mechanical properties. The aerogels are herein functionalized with electrically conducting poly(3,4‐ethylenedioxythiophene) to demonstrate their potential use in the fields of energy storage and sensing.
Cellulose nanofibril hydrogel mixed with an aqueous solution of sodium alginate is a novel bio-based material suitable for 3D printing of lightweight membranes with exquisite properties and ...sustainable traits. However, fun- damental knowledge enabling its applications in architectural design is still missing. Hence, this study examines the macro-scale features of lightweight membranes from cellulose nanofibril-alginate hydrogel, relevant for the design of various interior architectural products, such as wall claddings, ceiling tiles, room partitions, tapestries, and window screens. Through iterative prototyping experiments involving robotic 3D printing of lightweight membranes, their upscaling potential is demonstrated. Correlations between toolpath designs and shrinkages are also characterized, alongside an in-depth analysis of coloration changes upon ambient drying. Further, the tunability potential of various architectural features, enabled by bespoke 3D printing toolpath design, is discussed and exemplified. The aim is to expose the wide palette of design possibilities for cellulose nanofibril-alginate membranes, encompassing variations in curvature, porosity, translucency, texture, patterning, pliability, and feature sizes. The results comprise an important knowledge foundation for the design and manufacturing of custom lightweight architectural products from cellulose nanofibril-alginate hydrogel. These products could be applied in a variety of new bio-based, sustainable interior building systems, replacing environmentally harmful, fossil-based solutions.
Electrospinning of cellulose acetate (CA) was studied in relation to factors of solvent composition, polymer concentration, and flow rate to elucidate how the processing parameters impact electrospun ...CA structure. Fibrous cellulose-based mats were produced from electrospinning cellulose acetate (CA, Mn = 30,000, DS = 2.45) in acetone, acetone/isopropanol (2:1), and acetone/dimethylacetamide (DMAc) (2:1) solutions. The effect of CA concentration and flow rate was evaluated in acetone/DMAc (2:1) solution. The morphology of electrospun CA mats was impacted by solvent system, polymer concentration, and solution flow rate. Fibers produced from acetone and the mixture of acetone/isopropanol (2:1) exhibited a ribbon structure, while acetone/DMAc (2:1) system produced the common cylindrical fiber shape. It was determined that the electrospinning of 17 % CA solution in acetone/DMAc (2:1, w/w) produced fibers with an average fiber diameter in the submicron range and the lowest size distribution among the solvents tested. The solution flow rate had a power law relationship of 0.26 with the CA fiber size for 17 % CA in acetone/DMAc (2:1). Solvent composition and flow rate also impacted the stability of the network structure of the electrospun fibers. Only samples from acetone/DMAc (2:1) at solution flow rates equal or higher than 1 mL/h produced fibrous meshes that were able to preserve their original network structure after deacetylation. These samples after regeneration showed no residual DMAc and exhibited no cytotoxic effects on mammalian cells.
This study presents a new innovative method where electrospinning is used to coat single microfibers with nanofibers. The nanofiber-coated microfibers can be formed into scaffolds with the combined ...benefits of tailored porosity for cellular infiltration and nanostructured surface morphology for cell growth. The nanofiber coating is obtained by using a grounded collector rotating around the microfiber, to establish an electrical field yet allow collection of nanofibers on the microfiber. A Teflon tube surrounding the fibers and collector is used to force the nanofibers to the microfiber. Polycaprolactone nanofibers were electrospun onto polylactic acid microfibers and scaffolds of 95 and 97% porosities were made. Human chondrocytes were seeded on these scaffolds and on reference scaffolds of purely nanofibers and microfibers. Thereafter, cellular infiltration was investigated. The results indicated that scaffold porosity had great effects on cellular infiltration, with higher porosity resulting in increased infiltration, thereby confirming the advantage of the presented method.
In vivo biocompatibility of bacterial cellulose Helenius, Gisela; Bäckdahl, Henrik; Bodin, Aase ...
Journal of biomedical materials research. Part A,
February 2006, Letnik:
76A, Številka:
2
Journal Article
We prepared cellulose nanofibrils-based (CNF), alginate-based and single-walled carbon nanotubes (SWCNT)-based inks for freeform reversible embedding hydrogel (FRESH) 3D bioprinting of conductive ...scaffolds. The 3D printability of conductive inks was evaluated in terms of their rheological properties. The differentiation of human neuroblastoma cells (SH-SY5Y cell line) was visualized by the confocal microscopy and the scanning electron microscopy techniques. The expression of TUBB3 and Nestin genes was monitored by the RT-qPCR technique. We have demonstrated that the conductive guidelines promote the cell differentiation, regardless of using differentiation factors. It was also shown that the electrical conductivity of the 3D printed scaffolds could be tuned by calcium-induced crosslinking of alginate, and this plays a significant role on neural cell differentiation. Our work provides a protocol for the generation of a realistic in vitro 3D neural model and allows for a better understanding of the pathological mechanisms of neurodegenerative diseases.
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