| 1. |
- Bergman, Kristoffer, et al.
(författare)
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Injectable cell-free template for bone-tissue formation
- 2009
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Ingår i: Journal of Biomedical Materials Research-Part A. - : Wiley Periodicals, Inc. - 1549-3296 .- 1552-4965. ; 91A:4, s. 1111-1118
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Tidskriftsartikel (refereegranskat)abstract
- Here we present a novel injectable hydrogel which forms a template for de novo formation of bone tissue. Hydrogel formation takes place in situ in less than 1 min by the cross-linking of multifunctional hyaluronic acid and polyvinyl alcohol derivatives. Endogenous cells are recruited in vivo by incorporating bone morphogenetic protein-2 (BMP-2), a powerful promoter for osteogenic differentiation. The hydrogel was evaluated in vitro by performing a cell viability test and a release study and in vivo by a rat ectopic model. Examination by X-ray, microcomputed tomography, and histology revealed a significant bone formation at the target site for gels containing BMP-2, and a complete degradation was observed for gels without BMP-2 four weeks after injection. There were no signs of inflammation or foreign body response in either group and we believe that this system has the potential as an off-the-shelf injectable to be used where bone tissue is needed.
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| 2. |
- Bermejo-Velasco, Daniel, 1985-, et al.
(författare)
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Injectable hyaluronic acid hydrogels with the capacity for magnetic resonance imaging
- 2018
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Ingår i: Carbohydrate Polymers. - : Elsevier. - 0144-8617 .- 1879-1344. ; 197, s. 641-648
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Tidskriftsartikel (refereegranskat)abstract
- Monitoring hydrogel degradation in real time using noninvasive imaging techniques is of great interest for designing a scaffold in tissue engineering. We report the preparation of gadolinium (Gd)-labeled and injectable hyaluronic acid (HA) hydrogels that can be visualized using T-1- and T-2-weighted magnetic resonance imaging (MRI). An HA derivative functionalized with thiol and hydrazide was labeled using a diethylenetriaminepentaacetate complex modified with "clickable" dithiopyridyl functionalities (degree of modification was 3.77% with respect to HA repeat units). The HA derivative modified with cross-linkable groups and Gd complex exhibited relaxivities r(1) = 3.78 mM(-1)s(-1) and r(2) = 56.3 mM(-1)s(-1). A hydrazone hydrogel network was obtained by mixing Gd-labeled HA-hydrazide and HA-aldehyde derivatives. Enzymatic hydrogel degradation could be followed using MRI because the MR images showed great correlation with the hydrogel mass loss. Ex vivo MRI of injected Gd-labeled hydrogels demonstrated that they show a significant contrast difference (SNRcoronal = 456; SNRaxial = 459) from the surrounding tissues. These results indicate that our Gd-labeled HA hydrogel has great potential as an injectable biocompatible hydrogel that can be used for longitudinal tracking in vivo using MRI.
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| 3. |
- Berts, Ida, et al.
(författare)
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Polymeric Smart Coating Strategy for Titanium Implants
- 2014
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Ingår i: Advanced Engineering Materials. - : Wiley. - 1438-1656 .- 1527-2648. ; 16:11, s. 1340-1350
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Tidskriftsartikel (refereegranskat)abstract
- Hyaluronan based hydrogel coatings can mimic extracellular matrix components and incorporate growth factors that can be released during a progressive degradation while new tissue regenerates. This paper describes a structural characterization of a hydrogel coating made of modified hyaluronan polymers and how these coatings interact with bone morphogenetic protein-2 (BMP-2). Quartz crystal microbalance and neutron reflectivity measurements were used for in-situ, real-time measurements of the adsorption properties of polymers and proteins on smooth titanium oxide surfaces that mimic implant products in orthopedics. The adsorption of BMP-2 on a bare titanium oxide surface is compared to that on titanium oxide coated with different chemically modified hyaluronan, the most important being hyaluronan with bisphosphonate groups (HA-BP). The subsequent release of the BMP-2 from these hydrogel coatings could be triggered by calcium ions. The amount of adsorbed protein on the surfaces as well as the amount of released protein both depend on the type of hyaluronan coating. We conclude that HA-BP coated titanium oxide surfaces provide an excellent material for growth factor delivery in-vivo.
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| 4. |
- Diba, Mani, et al.
(författare)
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Exploiting Bisphosphonate-Bioactive-Glass Interactions for the Development of Self-Healing and Bioactive Composite Hydrogels
- 2016
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Ingår i: Macromolecular rapid communications. - : Wiley. - 1022-1336 .- 1521-3927. ; 37:23, s. 1952-1959
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Tidskriftsartikel (refereegranskat)abstract
- Hydrogels are widely recognized as promising candidates for various biomedical applications, such as tissue engineering. Recently, extensive research efforts have been devoted to the improvement of the biological and mechanical performance of hydrogel systems by incorporation of functional groups and/or inorganic particles in their composition. Bisphosphonates are a class of drugs, commonly used for treatment of osteoporosis, which exhibit a strong binding affinity for hydroxyapatite. In this study, the binding affinity of a bisphosphonate-functionalized polymer, hyaluronan, toward a bioactive glass (i.e., 45S5 Bioglass) is evaluated using force-distance measurements with atomic force microscopy. The strong interaction between bisphosphonate and bioactive glass is then exploited to develop organic-inorganic composite hydrogels and the viscoelastic and self-healing ability of these materials are investigated. Finally, the stability and mineralization behavior of these hydrogels are evaluated in simulated body fluid. Following this approach, injectable, bioactive and self-healing organic-inorganic composite hydrogels are produced, which mineralize abundantly and rapidly in simulated body fluid. These properties render these composite gels suitable for applications in bone-tissue engineering.
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| 5. |
- Han, Yuanyuan, et al.
(författare)
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Graphene Based Mechanical Biosensor by Employing Non-covalent Stacking Functionalization
- 2019
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Herein we demonstrate a novel methodology to achieve mechanical biosensor by employing the distinguished interaction forces between the atomic force microscope (AFM) probe and sensor surfaces as the response signal. This mechanical biosensor is fabricated by utilizing the non-covalent π-π stacking of pyrene-maltose onto graphene surfaces with Concanavalin A (Con A) as a target protein. The atomic resolution scanning tunneling microscopy (STM) images indicate the successful formation of the self-assembled and densely packed pyrene-maltose layer on the sensor surface, which gives distinct atomic lattice structure as compared to pristine graphene. This mechanical biosensor exhibits detection of Con A with the sensitivity down to nanomolar level. Therefore, this proposed mechanical biosensor has the potential to be employed in a variety of bio-sensing applications.
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| 6. |
- Han, Yuanyuan, et al.
(författare)
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Optimization and analysis of pyrene-maltose functionalized graphene surfaces for Con A detection
- 2020
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Ingår i: Applied Surface Science. - : ELSEVIER. - 0169-4332 .- 1873-5584. ; 510
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Tidskriftsartikel (refereegranskat)abstract
- Utilizing the non-covalent pi-pi stacking of pyrene functionalized molecules onto graphene surfaces has achieved great success in the detection of various bio-objects, while the fundamental investigations on surface modifications stills remain rarely exploited. Here, we report the nano and atomic scale analysis of the pi-pi stacking functionalized graphene surface regarding to its surface topography, molecular self-assembly as well as process optimizations. The 'amphipathic' molecule, pyrene-maltose, is used for the non-covalent functionalization of graphene and systematical analysis is performed to understand the influence of different solvents on the molecular surface arrangement. Atomic force microscopy (AFM) and spectroscopy analysis indicate the successful formation of pyrene-maltose layer on graphene surface and it is further confirmed by scanning tunneling microscopy, depicting the self-assembled and densely packed pyrene-maltose layer that give distinguished and ordered diamond-shape lattice as compared to triangular lattice in pristine graphene. We also demonstrated that the interfacial adhesion forces between the AFM probe and the functionalized surfaces allow the detection of the lectin protein Concavalin A through selective absorption. This work provides essential evidence of the pi-pi interactions between pyrene molecules and graphene, and the AFM based adhesion measurement also has the potential to be employed in a variety of bio-detection applications.
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| 7. |
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| 8. |
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| 9. |
- Hilborn, Jöns, et al.
(författare)
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Preparing Bone Using an Injectable Hydrogel Scaffold
- 2008
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Ingår i: TERMIS EU 2008 Porto Meeting June 22–26, 2008 Porto Congress Center–Alfândega Portugal. - : Mary Ann Liebert Inc.. ; , s. 769-770
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Hulsart-Billström, Gry, et al.
(författare)
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Bisphosphonate-Linked Hyaluronic Acid Hydrogel Sequesters and Enzymatically Releases Active Bone Morphogenetic Protein-2 for Induction of Osteogenic Differentiation
- 2013
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 14:9, s. 3055-3063
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Tidskriftsartikel (refereegranskat)abstract
- Regeneration of bone by delivery of bone morphogenetic proteins (BMPs) from implantable scaffolds is a promising alternative to the existing autologous bone grafting procedures. Hydrogels are used extensively in biomaterials as delivery systems for different growth factors. However, a controlled release of the growth factors is necessary to induce bone formation, which can be accomplished by various chemical functionalities. Herein we demonstrate that functionalization of a hyaluronan (HA) hydrogel with covalently linked bisphosphonate (BP) ligands provides efficient sequestering of BMP-2 in the resulting HA-BP hydrogel. The HA-BP hydrogel was investigated in comparison with its analogue lacking BP groups (HA hydrogel). While HA hydrogel released 100% of BMP-2 over two weeks, less than 10% of BMP-2 was released from the HA-BP hydrogel for the same time. We demonstrate that the sequestered growth factor can still be released by enzymatic degradation of the HA-BP hydrogel. Most importantly, entrapment of BMP-2 in HA-BP hydrogel preserves the growth factor bioactivity, which was confirmed by induction of osteogenic differentiation of mesenchymal stem cells (MSCs) after the cells incubation with the enzymatic digest of the hydrogel. At the same time, the hydrogels degradation products were not toxic to MSCs and osteoblasts. Furthermore, BP-functionalization of HA hydrogels promotes adhesion of the cells to the surface of HA hydrogel. Altogether, the present findings indicate that covalent grafting of HA hydrogel with BP groups can alter the clinical effects of BMPs in bone tissue regeneration.
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