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| 5. |
- Apelgren, Peter, et al.
(författare)
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In Vivo Human Cartilage Formation in Three-Dimensional Bioprinted Constructs with a Novel Bacterial Nanocellulose Bioink
- 2019
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Ingår i: Acs Biomaterials Science & Engineering. - : American Chemical Society (ACS). - 2373-9878. ; 5:5, s. 2482-2490
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Tidskriftsartikel (refereegranskat)abstract
- Bacterial nanocellulose (BNC) is a 3D network of nanofibrils exhibiting excellent biocompatibility. Here, we present the aqueous counter collision (ACC) method of BNC disassembly to create bioink with suitable properties for cartilage-specific 3D-bioprinting. BNC was disentangled by ACC, and fibril characteristics were analyzed. Bioink printing fidelity and shear-thinning properties were evaluated. Cell-laden bioprinted grid constructs (5 X 5 X 1 mm(3)) containing human nasal chondrocytes (10 M mL(-1)) were implanted in nude mice and explanted after 30 and 60 days. Both ACC and hydrolysis resulted in significantly reduced fiber lengths, with ACC resulting in longer fibrils and fewer negative charges relative to hydrolysis. Moreover, ACC-BNC bioink showed outstanding printability, postprinting mechanical stability, and structural integrity. In vivo, cell-laden structures were rapidly integrated, maintained structural integrity, and showed chondrocyte proliferation, with 32.8 +/- 13.8 cells per mm(2) observed after 30 days and 85.6 +/- 30.0 cells per mm(2) at day 60 (p = 0.002). Furthermore, a full-thickness skin graft was attached and integrated completely on top of the 3D-bioprinted construct. The novel ACC disentanglement technique makes BNC biomaterial highly suitable for 3D-bioprinting and clinical translation, suggesting cell-laden 3D-bioprinted ACC-BNC as a promising solution for cartilage repair.
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- Bordoni, Matteo, et al.
(författare)
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3D Printed Conductive Nanocellulose Scaffolds for the Differentiation of Human Neuroblastoma Cells
- 2020
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Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- 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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- Hu, Liangbing, et al.
(författare)
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Transparent and conductive paper from nanocellulose fibers
- 2013
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Ingår i: Energy & Environmental Science. - 1754-5692 .- 1754-5706. ; 6:2, s. 513-518
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Tidskriftsartikel (refereegranskat)abstract
- Here we report on a novel substrate, nanopaper, made of cellulose nanofibrils, an earth abundant material. Compared with regular paper substrates, nanopaper shows superior optical properties. We have carried out the first study on the optical properties of nanopaper substrates. Since the size of the nanofibrils is much less than the wavelength of visible light, nanopaper is highly transparent with large light scattering in the forward direction. Successful depositions of transparent and conductive materials including tin-doped indium oxide, carbon nanotubes and silver nanowires have been achieved on nanopaper substrates, opening up a wide range of applications in optoelectronics such as displays, touch screens and interactive paper. We have also successfully demonstrated an organic solar cell on the novel substrate.
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| 13. |
- Karabulut, Erdem, 1983-, et al.
(författare)
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Adhesive Layer-by-Layer Films of Carboxymethylated Cellulose Nanofibril Dopamine Covalent Bioconjugates Inspired by Marine Mussel Threads
- 2012
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 6:6, s. 4731-4739
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Tidskriftsartikel (refereegranskat)abstract
- The preparation of multifunctional films and coatings from sustainable, low-cost raw materials has attracted considerable interest during the past decade. In this respect, cellulose-based products possess great promise due not only to the availability of large amounts of cellulose in nature but also to the new classes of nanosized and well-characterized building blocks of cellulose being prepared from trees or annual plants. However, to fully utilize the inherent properties of these nanomaterials, facile and also sustainable preparation routes are needed. In this work, bioinspired hybrid conjugates of carboxymethylated cellulose nanofibrils (CNFC) and dopamine (DOPA) have been prepared and layer-by-layer (LbL) films of these modified nanofibrils have been built up in combination with a branched polyelectrolyte, polyethyleneimine (PEI), to obtain robust, adhesive, and wet-stable nanocoatings on solid surfaces. It is shown that the chemical functionalization of CNFCs with DOPA molecules alters their conventional properties both in liquid dispersion and at the interface and also influences the LbL. film formation by reducing the electrostatic interaction. Although the CNFC-DOPA conjugates show a lower colloidal stability in aqueous dispersions due to charge suppression, it was possible to prepare the LbL films through the consecutive deposition of the building blocks. Adhesive forces between muttilayer films prepared using chemically functionalized CNFCs and a silica probe are much stronger in the presence of Fe3+ than those between a multilayer film prepared from unmodified nanofibrils and a silica probe. The present work demonstrates a facile way to prepare chemically functionalized cellulose nanofibrils whereby more extended applications can produce novel cellulose-based materials with different functionalities.
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| 14. |
- Karabulut, Erdem, 1983-
(författare)
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Functional Layer-by-Layer films and aerogels of cellulose nanofibrils
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the preparation of functional Layer-by-Layer (LbL) films of cellulose nanofibrils (CNFs) and polyelectrolytes. LbL films ranging in thickness from 10 nm to 5 μm were deposited onto both solid surfaces and porous nanocellulose aerogels in order to prepare functional surfaces and materials.The LbL deposition technique relies on the consecutive deposition from aqueous solution of macromolecules, in many cases polyelectrolytes, nano-particles, carbon nanotubes (CNTs) and biological molecules such as peptides and proteins, containing complementary charged groups to form complex thin films with a thickness from a few nanometers to a few micrometers. Unless otherwise stated, the LbL films described in the present thesis were assembled either by dipping a solid support into the dispersions/solutions or by filtering the dispersions through the porous support.In Paper I, freestanding layer-by-layer (LbL) films of anionic CNFs and a branched cationic polyelectrolyte, polyethyleneimine (PEI), were prepared and characterized in terms of their structural and mechanical properties. The consecutive build-up of PEI and CNFs on a hydroxylated and trifunctional organosilane-coated silicon substrate was monitored with X-ray photoelectron spectroscopy, a quartz crystal microbalance with dissipation and a dual polarization interferometry technique. Modification of the supporting substrate with hydrophobic molecules to form a thin precursor layer made it possible to peel the films from the substrate and perform tensile tests using a dynamic mechanical analysis method.In Paper II, a bio-mimetic surface modification approach was applied to prepare of adhesive LbL films of CNFs and PEI. Dopamine molecules bearing catechol groups were attached covalently to the fibril surface using carbodiimide-chemistry. The fibrils were cross-linked through the catechol groups to form organometallic complexes. The colloidal, interfacial and adhesive properties of the modified CNF differed considerably from those of their non-modified analogs. The degree of chemical modification had a significant influence on the LbL film deposition as well as on the colloidal properties of the CNF in aqueous dispersion. Metal-ion-induced complexation of the catechol groups with Fe3+ led to a strong adhesion of the thin films prepared with modified CNF to hydrophobic surfaces such as polystyrene.In Paper III, we report a robust and rapid LbL film deposition method for the preparation of a supercapacitor. The porous electrodes of single-wall CNTs and PEI were prepared by the filter-deposition technique onto a wet-resilient CNF aerogel. It has been shown that the cross-linked aerogels have an elasticity that eliminates the structural deformation over the filtration process. The charge density of the fibrils increased significantly due to the chemical structure of the cross-linker (BTCA). We demonstrate that the enhanced compressive strength, super elasticity in water and high charge density create a novel porous electrode structure for electrical charge storage devices.In papers IV and V, the light-weight, flexible and conductive thin papers and aerogels of cellulose nanofibrils were used for the preparation of energy storage devices. It has been shown that the strong interaction of CNF with electronically active hydrophilic nanomaterials such as functionalized carbon nanotubes makes it possible to prepare efficient energy storage devices. The unique properties of CNF-based materials such as high mechanical stiffness, elasticity in water and high porosity eliminate the common mechanical issues upon cycling of supercapacitors and improve the overall device performance.
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| 15. |
- Karabulut, Erdem, 1983-
(författare)
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Tailored layer-by-layer films of nanofibrillated cellulose
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The preparation of multifunctional films, coatings and membranes from natural, sustainable and low-cost raw materials has attracted considerable interest during the last decade. In this respect, cellulose-based products possess a great promise for research and industry due both to the availability of large amounts of material in nature and to the preparation of new classes of nano-sized and well-characterized building-blocks of cellulose from trees or annual plants. This thesis deals with the preparation of nanofibrillated cellulose (NFC)-based layer-by-layer (LbL) films. The LbL deposition technique relies on the consecutive deposition of charged materials, in many cases polyelectrolytes, nano-particles and biological macromolecules, containing complementary charged groups from aqueous solution to form complex thin films with a thickness from nanometers to a few micrometers. The negatively charged carboxymethylated cellulose nanofibrils with a diameter of 3-5 nm and a length of 2-3 μm have been combined with a positively charged and hyperbranched polyelectrolyte, polyethyleneimine (PEI), to build-up multilayer films on solid substrates. In the first study, self-supporting layer-by-layer (LbL) films of anionic carboxymethylated cellulose nanofibrils (NFC) and a cationic branched polyelectrolyte, polyethyleneimine (PEI), have been prepared and characterized in terms of their structural and mechanical properties. The consecutive build-up of PEI and NFC on a hydroxylated and trifunctional organosilanecoated silicon substrate was monitored with X-ray photoelectron spectroscopy (XPS), quartz crystal microbalance with dissipation (QCM-D) and dual polarization interferometry (DPI) techniques. The hydrophobic functionalization of the supporting substrate with trichlorosilanes made it possible to easily peel off the films from the substrate and perform tensile tests using a dynamic mechanical analysis (DMA) method. The need to overcome some critical features of the cellulose-based materials such as weak wet-stability and high hydrophilicity was the basis of a study on nanofibril functionalization. In this respect, a biomimetic approach inspired by marine mussel threads was adopted by chemical modification of the nanofibrils with dopamine (DOPA) molecules, as shown in the second study. As expected, the colloidal, interfacial and adhesion properties of the modified NFC differed considerably from those of their non-modified analogs. The degree of chemical modification had a significant effect on the LbL film deposition as well as on the colloidal properties of the NFC in aqueous dispersions. Moreover, metal-ion-induced complexation of the catecholic groups with Fe3+ led to a strong adhesion of the thin films prepared with modified NFC to hydrophobic surfaces such as polyethylene.
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| 17. |
- Kuzmenko, Volodymyr, 1987, et al.
(författare)
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Tailor-made conductive inks from cellulose nanofibrils for 3D printing of neural guidelines
- 2018
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Ingår i: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617. ; 189, s. 22-30
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Tidskriftsartikel (refereegranskat)abstract
- Neural tissue engineering (TE), an innovative biomedical method of brain study, is very dependent on scaffolds that support cell development into a functional tissue. Recently, 3D patterned scaffolds for neural TE have shown significant positive effects on cells by a more realistic mimicking of actual neural tissue. In this work, we present a conductive nanocellulose-based ink for 3D printing of neural TE scaffolds. It is demonstrated that by using cellulose nanofibrils and carbon nanotubes as ink constituents, it is possible to print guidelines with a diameter below 1 mm and electrical conductivity of 3.8 × 10 −1 S cm −1 . The cell culture studies reveal that neural cells prefer to attach, proliferate, and differentiate on the 3D printed conductive guidelines. To our knowledge, this is the first research effort devoted to using cost-effective cellulosic 3D printed structures in neural TE, and we suppose that much more will arise in the near future.
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- Nagarajan, Neerajha, et al.
(författare)
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Enabling personalized implant and controllable biosystem development through 3D printing
- 2018
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Ingår i: Biotechnology Advances. - : Elsevier BV. - 0734-9750. ; 36:2, s. 521-533
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Forskningsöversikt (refereegranskat)abstract
- The impact of additive manufacturing in our lives has been increasing constantly. One of the frontiers in this change is the medical devices. 3D printing technologies not only enable the personalization of implantable devices with respect to patient-specific anatomy, pathology and biomechanical properties but they also provide new opportunities in related areas such as surgical education, minimally invasive diagnosis, medical research and disease models. In this review, we cover the recent clinical applications of 3D printing with a particular focus on implantable devices. The current technical bottlenecks in 3D printing in view of the needs in clinical applications are explained and recent advances to overcome these challenges are presented. 3D printing with cells (bioprinting); an exciting subfield of 3D printing, is covered in the context of tissue engineering and regenerative medicine and current developments in bioinks are discussed. Also emerging applications of bioprinting beyond health, such as biorobotics and soft robotics, are introduced. As the technical challenges related to printing rate, precision and cost are steadily being solved, it can be envisioned that 3D printers will become common on-site instruments in medical practice with the possibility of custom-made, on-demand implants and, eventually, tissue engineered organs with active parts developed with biorobotics techniques.
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| 20. |
- Pedrotty, Dawn M., et al.
(författare)
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Three-Dimensional Printed Biopatches With Conductive Ink Facilitate Cardiac Conduction When Applied to Disrupted Myocardium
- 2019
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Ingår i: Circulation: Arrhythmia and Electrophysiology. - 1941-3149 .- 1941-3084. ; 12:3
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reentrant ventricular arrhythmias are a major cause of sudden death in patients with structural heart disease. Current treatments focus on electrically homogenizing regions of scar contributing to ventricular arrhythmia with ablation or altering conductive properties using antiarrhythmic drugs. The high conductivity of carbon nanotubes may allow restoration of conduction in regions where impaired electrical conduction results in functional abnormalities. We propose a new concept for arrhythmia treatment using a stretchable, flexible biopatch with conductive properties to attempt to restore conduction across regions in which activation is disrupted. METHODS: Carbon nanotube patches composed of nanofibrillated cellulose/single-walled carbon nanotube ink 3-dimensionally printed in conductive patterns onto bacterial nanocellulose were developed and evaluated for conductivity, flexibility, and mechanical properties. The patches were applied on 6 canines to epicardium before and after surgical disruption. Electroanatomic mapping was performed on normal epicardium, then repeated over surgically disrupted epicardium, and then finally with the patch applied passively. RESULTS: We developed a 3-dimensional printable carbon nanotube ink complexed on bacterial nanocellulose that was (1) expressable through 3-dimensional printer nozzles, (2) electrically conductive, (3) flexible, and (4) stretchable. Six canines underwent thoracotomy, and, during epicardial ventricular pacing, mapping was performed. We demonstrated disruption of conduction after surgical incision in all 6 canines based on activation mapping. The patch resulted in restored conduction based on mapping and assessment of conduction direction and velocities in all canines. CONCLUSIONS: We have demonstrated 3-dimensional custom-printed electrically conductive carbon nanotube patches can be surgically manipulated to improve cardiac conduction when passively applied to surgically disrupted epicardial myocardium in canines.
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| 21. |
- van Zyl, Martin, et al.
(författare)
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Injectable conductive hydrogel restores conduction through ablated myocardium
- 2020
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Ingår i: Journal of Cardiovascular Electrophysiology. - : Wiley. - 1045-3873 .- 1540-8167. ; 31:12, s. 3293-3301
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Therapies for substrate-related arrhythmias include ablation or drugs targeted at altering conductive properties or disruption of slow zones in heterogeneous myocardium. Conductive compounds such as carbon nanotubes may provide a novel personalizable therapy for arrhythmia treatment by allowing tissue homogenization. Methods A nanocellulose carbon nanotube-conductive hydrogel was developed to have conduction properties similar to normal myocardium. Ex vivo perfused canine hearts were studied. Electroanatomic activation mapping of the epicardial surface was performed at baseline, after radiofrequency ablation, and after uniform needle injections of the conductive hydrogel through the injured tissue. Gross histology was used to assess distribution of conductive hydrogel in the tissue. Results The conductive hydrogel viscosity was optimized to decrease with increasing shear rate to allow expression through a syringe. The direct current conductivity under aqueous conduction was 4.3 x 10(-1) S/cm. In four canine hearts, when compared with the homogeneous baseline conduction, isochronal maps demonstrated sequential myocardial activation with a shift in direction of activation to surround the edges of the ablated region. After injection of the conductive hydrogel, isochrones demonstrated conduction through the ablated tissue with activation restored through the ablated tissue. Gross specimen examination demonstrated retention of the hydrogel within the tissue. Conclusions This proof-of-concept study demonstrates that conductive hydrogel can be injected into acutely disrupted myocardium to restore conduction. Future experiments should focus on evaluating long-term retention and biocompatibility of the hydrogel through in vivo experimentation.
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