| 1. |
- Chen, Song, et al.
(författare)
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Novel Fast-Setting Mineral Trioxide Aggregate : Its Formulation, Chemical-Physical Properties, and Cytocompatibility
- 2018
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 10:24, s. 20334-20341
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Tidskriftsartikel (refereegranskat)abstract
- One of the main drawbacks that limits the application of mineral trioxide aggregate (MTA) in dental field is its long setting time. Mineral trioxide aggregate with accelerated setting properties and excellent chemical-physical and biological properties is still required. In this study, an innovative mineral trioxide aggregate, which consists of calcium silicates, calcium aluminates, and zirconium oxide, was designed to obtain fast-setting property. The optimized formulation can achieve initial setting in 10 min and final setting in 15 min, which are much faster than commercial mineral trioxide aggregate. In addition, the optimized fast-setting MTA showed adequate radiopacity and good biocompatibility. The ion concentrations after storage in water for 1 day were 52.3 mg/L Ca, 67.7 mg/L Al, 48.8 mg/L Si, and 11.7 mg/L Mg. The hydration products of hardened cements were investigated by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared, showing the accelerated setting time was due to the formation of honeycomb-like calcium silicate hydrate gel. The novel MTA could be a promising material for dental applications.
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| 2. |
- Han, Yuanyuan, et al.
(författare)
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Flexible conductive silk-PPy hydrogel toward wearable electronic strain sensors
- 2022
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Ingår i: Biomedical Materials. - : IOP Publishing Ltd. - 1748-6041 .- 1748-605X. ; 17:2
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Tidskriftsartikel (refereegranskat)abstract
- Conductive hydrogels have been studied as promising materials for the flexible and wearable bioelectronics, because of their unique electrical and mechanical properties. Addition of conducting polymers in biomaterial-based hydrogel matrix is a simple yet effective way to construct hydrogels with good conductivity and flexibility. In this work, a conductive hydrogel composed by a silk hydrogel and a conducting polymer, polypyrrole (PPy), is developed via in situ polymerization of pyrrole into the silk fibroin network. The silk-PPy hydrogel shows high conductivity (26 S m(-1)), as well as sensitive and fast responses to corresponding conformation changes. Taking advantages of these properties, flexible and wearable strain sensors are proposed for the monitoring of various body movements, which can detect both the large and subtle human motions with good sensitivity, reproducibility and stability. The hybridization of biomaterials and conducting polymers endows the multifunctions of the conductive hydrogels, thus showing considerable potentials in the advancement of the wearable electronics.
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| 3. |
- Kheirabadi, Malihe, et al.
(författare)
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In situ forming interpenetrating hydrogels of hyaluronic acid hybridized with iron oxide nanoparticles
- 2015
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Ingår i: Biomaterials Science. - : Royal Society of Chemistry (RSC). - 2047-4830 .- 2047-4849. ; 3:11, s. 1466-1474
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Tidskriftsartikel (refereegranskat)abstract
- Four derivatives of hyaluronic acid (HA) bearing thiol (HA-SH), hydrazide (HA-hy), 2-dithiopyridyl (HA-SSPy), and aldehyde groups (HA-al) respectively were synthesized. Thiol and 2-dithiopyridyl as well as hydrazide and aldehyde make up two chemically orthogonal pairs of chemo-selective functionalities that allow in situ formation of interpenetrating (IPN) disulfide and hydrazone networks simultaneously upon the mixing of the above derivatives at once. The formation of IPN was demonstrated by comparing it with the formulations of the same total HA concentration but lacking one of the reactive components. The hydrogel composed of all four components was characterized by a larger elastic modulus than those of the control single networks (either disulfide or hydrazone) and the three component formulations gave the softest hydrogels. Moreover, a hydrazone cross-linkage was designed to contain a 1,2-diol fragment. This allowed us to partially disassemble one type of network in the IPN leaving another one unaffected. In particular, treatment of the IPN with either sodium periodate or dithiothreitol resulted in disassembly of the hydrazone and disulfide networks respectively and thus softening of the hydrogel. Contrarily, the single network hydrogels completely dissolved under the corresponding conditions. In corroboration with this, enzymatic degradation of the IPN by hyaluronidase was also substantially slower than the degradation of the single networks. In order to further improve the mechanical properties of the elaborated injectable IPN, it has been in situ hybridized with iron oxide nanoparticles (IONPs). The mesh size of the IPN was smaller than the size of the IONPs resulting in the retention of nanoparticles in the matrix under equilibrium swelling conditions. However, these nanoparticles were released upon enzymatic degradation suggesting their use as MRI tags for non-invasive tracking of the hydrogel material in vivo. Additionally, this injectable hybridized hydrogel with encapsulated IONPs can be used in hyperthermia cancer therapy.
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| 4. |
- Kim, Yang-Hee, et al.
(författare)
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Bisphosphonate nanoclay edge-site interactions facilitate hydrogel self-assembly and sustained growth factor localization
- 2020
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Nanoclays have generated interest in biomaterial design for their ability to enhance the mechanics of polymeric materials and impart biological function. As well as their utility as physical cross-linkers, clays have been explored for sustained localization of biomolecules to promote in vivo tissue regeneration. To date, both biomolecule-clay and polymer-clay nanocomposite strategies have utilised the negatively charged clay particle surface. As such, biomolecule-clay and polymer-clay interactions are set in competition, potentially limiting the functional enhancements achieved. Here, we apply specific bisphosphonate interactions with the positively charged clay particle edge to develop self-assembling hydrogels and functionalized clay nanoparticles with preserved surface exchange capacity. Low concentrations of nanoclay are applied to cross-link hyaluronic acid polymers derivatised with a pendant bisphosphonate to generate hydrogels with enhanced mechanical properties and preserved protein binding able to sustain, for over six weeks in vivo, the localized activity of the clinically licensed growth factor BMP-2.
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| 5. |
- Li, Ya, et al.
(författare)
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Click chemistry-based biopolymeric hydrogels for regenerative medicine
- 2021
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Ingår i: Biomedical Materials. - : Institute of Physics Publishing (IOPP). - 1748-6041 .- 1748-605X. ; 16:2
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Forskningsöversikt (refereegranskat)abstract
- Click chemistry is not a single specific reaction, but describes ways of generating products which emulate examples in nature. Click reactions occur in one pot, are not disturbed by water, generate minimal and inoffensive byproducts, and are characterized by a high thermodynamic driving force, driving the reaction quickly and irreversibly towards a high yield of a single reaction product. As a result, over the past 15 years it has become a very useful bio-orthogonal method for the preparation of chemical cross-linked biopolymer-based hydrogel, in the presence of e.g. growth factors and live cells, or in-vivo. Biopolymers are renewable and non-toxic, providing a myriad of potential backbone toolboxes for hydrogel design. The goal of this review is to summarize recent advances in the development of click chemistry-based biopolymeric hydrogels, and their applications in regenerative medicine. In particular, various click chemistry approaches, including copper-catalyzed azide-alkyne cycloaddition reactions, copper-free click reactions (e.g. the Diels-Alder reactions, the strain-promoted azide-alkyne cycloaddition reactions, the radical mediated thiol-ene reactions, and the oxime-forming reactions), and pseudo-click reactions (e.g. the thiol-Michael addition reactions and the Schiff base reactions) are highlighted in the first section. In addition, numerous biopolymers, including proteins (e.g. collagen, gelatin, silk, and mucin), polysaccharides (e.g. hyaluronic acid, alginate, dextran, and chitosan) and polynucleotides (e.g. deoxyribonucleic acid), are discussed. Finally, we discuss biopolymeric hydrogels, cross-linked by click chemistry, intended for the regeneration of skin, bone, spinal cord, cartilage, and cornea. This article provides new insights for readers in terms of the design of regenerative medicine, and the use of biopolymeric hydrogels based on click chemistry reactions.
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| 6. |
- Lunzer, Markus, et al.
(författare)
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A Modular Approach to Sensitized Two-Photon Patterning of Photodegradable Hydrogels
- 2018
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Ingår i: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773. ; 57:46, s. 15122-15127
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Tidskriftsartikel (refereegranskat)abstract
- Photodegradable hydrogels have emerged as useful platforms for research on cell function, tissue engineering, and cell delivery as their physical and chemical properties can be dynamically controlled by the use of light. The photo-induced degradation of such hydrogel systems is commonly based on the integration of photolabile o-nitrobenzyl derivatives to the hydrogel backbone, because such linkers can be cleaved by means of one-and two-photon absorption. Herein we describe a cytocompatible click-based hydrogel containing o-nitrobenzyl ester linkages between a hyaluronic acid backbone, which is photodegradable in the presence of cells. It is demonstrated for the first time that by using a cyclic benzylidene ketone-based small molecule as photosensitizer the efficiency of the two-photon degradation process can be improved significantly. Biocompatibility of both the improved two-photon micropatterning process as well as the hydrogel itself is confirmed by cell culture studies.
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| 7. |
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| 8. |
- Porras, Ana Maria, et al.
(författare)
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Chemical micropatterning of hyaluronic acid hydrogels for controlled cell adhesion
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The blood brain barrier is constituted by endothelial cells, astrocytes and pericytes; and are organized into well structured units [1]. Standard cell culture techniques cannot recapitulate this organized structure. Hydrogels are an attractive scaffold due to their mechanical and chemical properties similar to those in body tissue[2] We propose the use of a photo-crosslinkable hyaluronic acid hydrogel as cell culture scaffold. Furthermore, chemical cues can be added into the hydrogel matrix to promote and control cell adhesion using UV lithography.
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| 9. |
- Porras, Ana Maria, et al.
(författare)
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Photopatterning of hyaluronic acid hydrogels for cell culture scaffolds
- 2016
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Konferensbidrag (refereegranskat)abstract
- Organs-on-chips technologies require the development of micro engineered devices to represent functional units of human organs. These devices use cell culture scaffolds to give support and structure for the cultured cells. Hydrogels are attractive scaffold materials, due to their high water content and because they are derived from natural polymers found in the extracellular matrix of different tissues in the human body. Hyaluronic acid can form hydrogels when functionalized with chemo-selective groups. These chemically cross-linked hydrogels can be modified with adhesion motifs, such as RGD peptides, to increase their biocompatibility and promote cell adhesion. In this work we use a photolithographic method to pattern the RGD peptide into distinct areas of the hyaluronic acid hydrogel with the aim to spatially control the cell attachment on the HA hydrogel scaffolds
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| 10. |
- Porras Hernandez, Ana Maria, et al.
(författare)
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A simplified approach to control cell adherence on biologically derived in vitro cell culture scaffolds by direct UV-mediated RGD linkage
- 2020
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Nature. - 0957-4530 .- 1573-4838. ; 31:10
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we present a method to fabricate a hyaluronic acid hydrogel with spatially controlled cell-adhesion properties based on photo-polymerisation cross-linking and functionalisation. The approach utilises the same reaction pathway for both steps meaning that it is user-friendly and allows for adaptation at any stage during the fabrication process. Moreover, the process does not require any additional cross-linkers. The hydrogel is formed by UV initiated radical addition reaction between acrylamide groups on the hyaluronic acid backbone. Cell adhesion is modulated by functionalising the adhesion peptide sequence RGD (arginine-glycine-aspartate) onto the hydrogel surface via radical mediated thiol-ene reaction using the non-reacted acrylamide groups. We show that 10 x 10 µm2 squares could be patterned with sharp features and a good resolution. The smallest area that could be patterned resulting in good cell adhesion was 25 x 25 µm2 squares, showing single-cell adhesion. Mouse brain endothelial cells adhered and remained in culture for up to 7 days on 100 x 100 µm2 square patterns. We see potential for this material combination for future use in novel organ-on-chip models and tissue engineering where the location of the cells is of importance and to further study endothelial cell biology.
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