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Publications (10 of 122) Show all publications
Oroujeni, M., Kaboudin, B., Xia, W., Jönsson, P. & Ossipov, D. A. (2018). Conjugation of cyclodextrin to magnetic Fe3O4 nanoparticles via polydopamine coating for drug delivery. Progress in organic coatings, 114, 154-161
Open this publication in new window or tab >>Conjugation of cyclodextrin to magnetic Fe3O4 nanoparticles via polydopamine coating for drug delivery
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2018 (English)In: Progress in organic coatings, ISSN 0300-9440, E-ISSN 1873-331X, Vol. 114, p. 154-161Article in journal (Refereed) Published
Abstract [en]

In this study, a novel magnetic nanocarrier for hydrophobic drugs (β-CD–PDA–MNPs) was fabricated using surface coating of Fe3O4 nanoparticles with polydopamine (PDA) followed by functionalization with 6-thio-β-cyclodextrin (6-thio-β-CD). The obtained magnetic nanoparticles were employed to investigate their interactions with diclofenac (DCF) as a model hydrophobic drug. The resulting β-CD–PDA–MNPs were characterized by various methods including transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM). The newly fabricated magnetic nanocarrier exhibited considerably higher drug loading capacity as compared for its analogue lacking CD ligands. Moreover, the release profile of DCF from β-CD–PDA–MNPs showed a burst release during the initial 8 h followed by the drug sustained release. Facile coating of magnetic nanoparticles with PDA was therefore a robust synthetic procedure for the conversion of the nanoparticles into a drug vehicle.

Keyword
Magnetic nanoparticles, β Cyclodextrin, Host-guest interactions, Diclofenac, Drug delivery
National Category
Medical Materials
Identifiers
urn:nbn:se:uu:diva-330899 (URN)10.1016/j.porgcoat.2017.10.007 (DOI)000417661100017 ()
Available from: 2017-10-06 Created: 2017-10-06 Last updated: 2018-02-02Bibliographically approved
Cui, S., Wang, X., Zhang, X., Xia, W., Tang, X., Lin, B., . . . Shen, X. (2018). Preparation of magnetic MnFe2O4-Cellulose aerogel composite and its kinetics and thermodynamics of Cu(II) adsorption. Cellulose (London), 25(1), 735-751
Open this publication in new window or tab >>Preparation of magnetic MnFe2O4-Cellulose aerogel composite and its kinetics and thermodynamics of Cu(II) adsorption
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2018 (English)In: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, no 1, p. 735-751Article in journal (Refereed) Published
Abstract [en]

In this paper, a MnFe2O4-Cellulose magnetic composite aerogel (MnCA) with high adsorption capacity was fabricated by in situ incorporating MnFe2O4 to regenerated cellulose hydrogel matrix, followed by CO2 supercritical drying. A green synthetic strategy was performed by using renewable cellulose materials, environmentally benign cellulose solvents and facile synthetic conditions. The results showed that the obtained magnetic cellulose aerogel had a continuous and tiered three dimensional network with interconnected fibrils of about 30 nm in width, which was similar to those of cellulose aerogel prepared from NaOH/urea solution via CO2 supercritical drying. Meanwhile, they had high specific surface areas of 236-288 m(2)/g and total pore volume of 0.55-0.88 cm(3)/g. In addition, the hybrid aerogel showed superparamagnetism with maximum saturation magnetization reaching up to 18.53 emu/g. The magnetic nanocomposite aerogel could be used for biological and environmental applications. The adsorption test showed that MnCA had rapid adsorption rate and excellent adsorption ability of removing heavy metal ions in aqueous solution which could attain to 63.3 mg/g within 100 min. Moreover, all the composite aerogels exhibited good reusability and could be easily reused from the water after adsorption.

Place, publisher, year, edition, pages
SPRINGER, 2018
Keyword
Magnetic aerogel, MnFe2O4-Cellulose, Composites, Copper ion, Adsorption
National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-342464 (URN)10.1007/s10570-017-1598-x (DOI)000419902600059 ()
Available from: 2018-02-26 Created: 2018-02-26 Last updated: 2018-02-26Bibliographically approved
Fu, L., Engqvist, H. & Xia, W. (2018). Spark plasma sintering of biodegradable Si3N4 bioceramic with Sr, Mg and Si as sintering additives for spinal fusion. Journal of the European Ceramic Society, 38(4), 2110-2119
Open this publication in new window or tab >>Spark plasma sintering of biodegradable Si3N4 bioceramic with Sr, Mg and Si as sintering additives for spinal fusion
2018 (English)In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 38, no 4, p. 2110-2119Article in journal (Refereed) Published
Abstract [en]

Silicon nitride (Si3N4) bioceramics with standard sintering additives (Al2O3 and Y2O3) are used in spinal fusion. Alternative Si3N4 bioceramics with biologically beneficial sintering additives could lead to improved osseoin- tegrative properties. The aim of this study is to obtain dense and strong Si3N4 bioceramics by using SrO, MgO and SiO2 as sintering additives, and evaluate the effect of these sintering additives on microstructures and properties of Si3N4 bioceramics. Raw powders with 10 wt% and 18 wt% sintering additives were sintered by spark plasma sintering. Samples sintered at 1750 °C, with an applied pressure of 60 MPa and a holding time of 3 min, showed the highest content of β-Si3N4 (94.9%). The mechanical properties of the developed Si3N4 bio- ceramics are comparable to the mechanical properties of currently used structural Si3N4 ceramics sintered with standard sintering additives (Al2O3 and Y2O3). The highest flexural strength of the developed Si3N4 bioceramics reached 1079 MPa. Ion release results showed that Sr2+,Mg2+ and Si4+ ions kept leaching out within 10 days’ immersion. The degradable Si3N4 bioceramics with adequate strength and biologically beneficial sintering ad- ditives show the promise for load bearing biomedical applications, such as spinal fusion.

National Category
Natural Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-331879 (URN)10.1016/j.jeurceramsoc.2017.10.003 (DOI)000424716700136 ()
Funder
Carl Tryggers foundation
Available from: 2017-10-19 Created: 2017-10-19 Last updated: 2018-04-06Bibliographically approved
Garbani, M., Xia, W., Rhyner, C., Prati, M., Scheynius, A., Malissen, B., . . . Terhorst-Molawi, D. (2017). Allergen-loaded strontium-doped hydroxyapatite spheres improve allergen-specific immunotherapy in mice. Allergy. European Journal of Allergy and Clinical Immunology, 72(4), 570-578
Open this publication in new window or tab >>Allergen-loaded strontium-doped hydroxyapatite spheres improve allergen-specific immunotherapy in mice
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2017 (English)In: Allergy. European Journal of Allergy and Clinical Immunology, ISSN 0105-4538, E-ISSN 1398-9995, Vol. 72, no 4, p. 570-578Article in journal (Refereed) Published
Abstract [en]

Background

Immunomodulatory interventions play a key role in the treatment of infections and cancer as well as allergic diseases. Adjuvants such as micro- and nanoparticles are often added to immunomodulatory therapies to enhance the triggered immune response. Here, we report the immunological assessment of novel and economically manufactured microparticle adjuvants, namely strontium-doped hydroxyapatite porous spheres (SHAS), which we suggest for the use as adjuvant and carrier in allergen-specific immunotherapy (ASIT).

Methods and Results

Scanning electron microscopy revealed that the synthesis procedure developed for the production of SHAS results in a highly homogeneous population of spheres. SHAS bound and released proteins such as ovalbumin (OVA) or the major cat allergen Fel d 1. SHAS-OVA were taken up by human monocyte-derived dendritic cells (mdDCs) and murine DCs and did not have any necrotic or apoptotic effects even at high densities. In a murine model of ASIT for allergic asthmatic inflammation we found that OVA released from subcutaneously injected SHAS-OVA led to a sustained stimulation of both CD4+ and CD8+ T-cells. ASIT with SHAS-OVA as compared to soluble OVA resulted in similar humoral responses but in a higher efficacy as assessed by symptom scoring.

Conclusion

We conclude that SHAS may constitute a suitable carrier and adjuvant for ASIT with great potential due to its unique protein-binding properties.

National Category
Medical Materials
Identifiers
urn:nbn:se:uu:diva-310479 (URN)10.1111/all.13041 (DOI)000397489400007 ()27590538 (PubMedID)
Funder
Swedish Research Council, 2013-5419
Available from: 2016-12-16 Created: 2016-12-16 Last updated: 2017-05-15Bibliographically approved
Ting, M., Jefferies, S. R., Xia, W., Engqvist, H. & Suzuki, J. B. (2017). Classification and Effects of Implant Surface Modification on the Bone: Human Cell-Based In Vitro Studies. Journal of Oral Implantology, 43(1), 58-83
Open this publication in new window or tab >>Classification and Effects of Implant Surface Modification on the Bone: Human Cell-Based In Vitro Studies
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2017 (English)In: Journal of Oral Implantology, ISSN 0160-6972, E-ISSN 1548-1336, Vol. 43, no 1, p. 58-83Article, review/survey (Refereed) Published
Abstract [en]

Implant surfaces are continuously being improved to achieve faster osseointegration and a stronger bone to implant interface. This review will present the various implant surfaces, the parameters for implant surface characterization, and the corresponding in vitro human cell-based studies determining the strength and quality of the bone-implant contact. These in vitro cell-based studies are the basis for animal and clinical studies and are the prelude to further reviews on how these surfaces would perform when subjected to the oral environment and functional loading.

Place, publisher, year, edition, pages
ALLEN PRESS INC, 2017
Keyword
titanium, dental implant, implant surface morphology, osseointegration, surface topography
National Category
Medical and Health Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-320997 (URN)10.1563/aaid-joi-D-16-00079 (DOI)000395366200011 ()27897464 (PubMedID)
Available from: 2017-04-28 Created: 2017-04-28 Last updated: 2017-04-28Bibliographically approved
Xia, W., Fu, L. & Engqvist, H. (2017). Critical cracking thickness of calcium phosphates biomimetic coating: Verification via a Singh-Tirumkudulu model. Ceramics International, 43, 15729-15734
Open this publication in new window or tab >>Critical cracking thickness of calcium phosphates biomimetic coating: Verification via a Singh-Tirumkudulu model
2017 (English)In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 43, p. 15729-15734Article in journal (Refereed) Published
Abstract [en]

Despite the many advantages of biomimetic calcium phosphates (CaPs) coatings, there is a troublesome problem of low cohesion in the coatings. The low cohesion originates from the absence of bonding between CaP crystals, leading to cracks during drying of the coatings. In this study, based on a simplified Singh-Tirumkudulu model, the critical cracking thickness (CCT) of biomimetic CaPs coatings has been calculated. CaPs crystal size is the key factor influencing the CCT, except for the particle's shear modulus. Biomimetic CaPs coatings with different thickness have been prepared by soaking Ti substrates with a transition layer of TiO2 (rutile) in Dulbecco's phosphate buffer saline solution (DPBS) for 1, 2, 4 and 6 weeks. The morphology, thickness, and whether cracks formed or not were evaluated by SEM. The simplified Singh and Tirumkudulu model has been verified in terms of our experimental results and data obtained from previous literatures. Via dedicated experiments and calculations it is concluded that a thickness of about approximately 2 gm is the critical value for a crack-free CaPs coating given that the CaPs crystal size is smaller than 100 nm. The model could be used in the future design of crack-free biomimetic coatings.

National Category
Medical Materials
Identifiers
urn:nbn:se:uu:diva-330143 (URN)10.1016/j.ceramint.2017.08.134 (DOI)000413175300158 ()
Available from: 2017-09-26 Created: 2017-09-26 Last updated: 2018-02-05Bibliographically approved
Li, H., Edin, F., Hayashi, H., Gudjonsson, O., Danckwardt-Lillieström, N., Engqvist, H., . . . Xia, W. (2017). Guided Growth of Auditory Neurons: Bioactive Particles Towards Gapless Neural - Electrode Interface. Biomaterials, 122, 1-9
Open this publication in new window or tab >>Guided Growth of Auditory Neurons: Bioactive Particles Towards Gapless Neural - Electrode Interface
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2017 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 122, p. 1-9Article in journal (Refereed) Published
Abstract [en]

Cochlear implant (CI) is a successful device to restore hearing. Despite continuous development, frequency discrimination is poor in CI users due to an anatomical gap between the auditory neurons and CI electrode causing current spread and unspecific neural stimulation. One strategy to close this anatomical gap is guiding the growth of neuron dendrites closer to CI electrodes through targeted slow release of neurotrophins. Biodegradable calcium phosphate hollow nanospheres (CPHSs) were produced and their capacity for uptake and release of neurotrophins investigated using I-125-conjugated glia cell line-derived neurotrophic factor (GDNF). The CPHSs were coated onto CI electrodes and loaded with neurotrophins. Axon guidance effect of slow-released neurotrophins from the CPHSs was studied in an in vitro 3D culture model. CPHS coating bound and released GDNF with an association rate constant 6.3 x 10(3) M(-1)s(-1) and dissociation rate 2.6 x 10(-5) s(-1), respectively. Neurites from human vestibulocochlear ganglion explants found and established physical contact with the GDNF-loaded CPHS coating on the CI electrodes placed 0.7 mm away. Our results suggest that neurotrophin delivery through CPHS coating is a plausible way to close the anatomical gap between auditory neurons and electrodes. By overcoming this gap, selective neural activation and the fine hearing for CI users become possible.

National Category
Medical and Health Sciences Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-276334 (URN)10.1016/j.biomaterials.2016.12.020 (DOI)000394472500001 ()28107660 (PubMedID)
Funder
Swedish Research Council, 2013-5419
Available from: 2016-03-07 Created: 2016-02-11 Last updated: 2018-02-08Bibliographically approved
Luo, J., Martinez-Casado, F. J., Balmes, O., Yang, J., Persson, C., Engqvist, H. & Xia, W. (2017). In-situ Synchrotron X-ray Diffraction Analysis of the Setting Process of Brushite Cement: Reaction and Crystal Growth. ACS Applied Materials and Interfaces, 9(41), 36392-36399
Open this publication in new window or tab >>In-situ Synchrotron X-ray Diffraction Analysis of the Setting Process of Brushite Cement: Reaction and Crystal Growth
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2017 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 41, p. 36392-36399Article in journal (Refereed) Published
Abstract [en]

Brushite cements are fast self-setting materials that can be used as bone substitute materials. Although tracing their fast setting process is a challenge, it is important for the understanding of the same, which in turn is important for the material’s further development and use in the clinics. In this study, the setting rate, phase formation, and crystal growth of brushite cements were quantitatively studied by in situ synchrotron powder X-ray diffraction (SXRD) on a time scale of seconds. The influence of reactant ratios and a retardant (citric acid) on the setting reaction were analyzed. To complement the in situ investigations, scanning electron microscopy was carried out for ex situ morphological evolution of crystals. The initial reaction followed a four-step process, including a fast nucleation induction period, nucleation, crystal growth, and completion of the setting. The brushite crystal size grew up to the micro scale within 1 min, and the brushite content increased linearly after the nucleation until all monocalcium phosphate monohydrate (MCPM; Ca(H2PO4)2·H2O) had dissolved within minutes, followed by a slow increase until the end of the monitoring. By adjusting the MCPM to the β-tricalcium phosphate (β-TCP, β-Ca3(PO4)2) ratio in the starting powders, the brushite/monetite ratio in the cements could be modified. In the presence of citric acid, the formation of brushite nuclei was not significantly retarded, whereas the increase in brushite content and the growth of crystal size were effectively hindered. The amount of monetite also increased by adding citric acid. This is the first time that the brushite setting process has been characterized in the first seconds and minutes of the reaction by SXRD.

Keyword
synchrotron X-ray diffraction, setting reaction process, brushite cement, crystal size, citric acid, MCPM/β-TCP ratio
National Category
Engineering and Technology Medical Materials Biomaterials Science
Research subject
Engineering Science with specialization in Materials Science
Identifiers
urn:nbn:se:uu:diva-330146 (URN)10.1021/acsami.7b10159 (DOI)000413503700092 ()
Available from: 2017-09-26 Created: 2017-09-26 Last updated: 2018-02-08Bibliographically approved
Yang, X., Xu, S., Chen, X., He, D., Ke, X., Zhang, L., . . . Gou, Z. (2017). Intra-bone marrow injection of trace elements co-doped calcium phosphate microparticles for the treatment of osteoporotic rat. Journal of Biomedical Materials Research. Part A, 105(5), 1422-1432
Open this publication in new window or tab >>Intra-bone marrow injection of trace elements co-doped calcium phosphate microparticles for the treatment of osteoporotic rat
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2017 (English)In: Journal of Biomedical Materials Research. Part A, ISSN 1549-3296, E-ISSN 1552-4965, Vol. 105, no 5, p. 1422-1432Article in journal (Refereed) Published
Abstract [en]

Osteoporotic femur fractures are the most common fragility fracture and account for approximately one million injuries per year. Local intervention by intra-marrow injection is potentially a good choice for preventing osteoporotic bone loss when the osteoporotic femoral fracture was treated. Previously, it was shown that trace element co-doped calcium phosphate (teCaP) implants could stimulate osteoporotic bone marrow mesenchymal stem cell activity in vitro and bone regeneration in femoral bone defects in osteoporotic animal models. They hypothesized that local intra-marrow injection of teCaP particles could improve bone function because the teCaP can sustain release of biologically essential inorganic minerals and improve bone remodeling in osteoporosis. The teCaP and CaP particles were synthesized in simulated body fluid with and without adding silicon, zinc and strontium ions. Female rats (8 months) were ovariectomized (OVX) or sham-operated, and then intervened in the femoral marrow space at 12 months old. Groups include: (1) saline water; (2) CaP particles; and (3) teCaP particles. After 2-3 months of intervention, the sham groups showed higher bone mineral density (MBD) in the femur, and teCaP group increased the BMD in the OVX groups. The compressive strength of the OVX-teCaP group was significantly higher than that in the OVX-CaP group. Significant differences between OVX-teCaP and OVX-CaP groups were found for bone mineral microarchitecture, bone mineral density, and trace mineral content, but not for feces composition. These results confirm the teCaP particles could suppress osteoporotic bone loss by local intramarrow injection. Therefore, this biomaterial could be used as a next-generation combination treatment for osteoporotic trauma and osteoporosis itself.

Keyword
antiosteoporosis, trace element, calcium phosphate, local intramarrow injection, osteoporotic fracture
National Category
Biomaterials Science Materials Engineering Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:uu:diva-321173 (URN)10.1002/jbm.a.36027 (DOI)000398211300019 ()28233417 (PubMedID)
Available from: 2017-05-12 Created: 2017-05-12 Last updated: 2017-05-12Bibliographically approved
Ingrassia, D., Sladkova, M., Pujari-Palmer, M., Xia, W., Engqvist, H. & de Peppo, G. M. (2017). Stem cell-mediated functionalization of titanium implants. Journal of materials science. Materials in medicine, 28(9), Article ID 133.
Open this publication in new window or tab >>Stem cell-mediated functionalization of titanium implants
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2017 (English)In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 28, no 9, article id 133Article in journal (Refereed) Published
Abstract [en]

Prosthetic implants are used daily to treat edentulous people and to restore mobility in patients affected by skeletal defects. Titanium (Ti) is the material of choice in prosthetics, because it can form a stable bond with the surrounding bone following implantation-a process known as osseointegration. Yet, full integration of prosthetic implants takes time, and fails in clinical situations characterized by limited bone quantity and/or compromised regenerative capacity, and in at-risk patients. Intense research efforts are thus made to develop new implants that are cost-effective, safe, and suited to every patient in each clinical situation. In this study, we tested the possibility to functionalize Ti implants using stem cells. Human induced pluripotent stem cell-derived mesenchymal progenitor (iPSC-MP) cells were cultured on Ti model disks for 2 weeks in osteogenic conditions. Samples were then treated using four different decellularization methods to wash off the cells and expose the matrix. The functionalized disks were finally sterilized and seeded with fresh human iPSC-MP cells to study the effect of stem cell-mediated surface functionalization on cell behavior. The results show that different decellularization methods produce diverse surface modifications, and that these modifications promote proliferation of human iPSC-MP cells, affect the expression of genes involved in development and differentiation, and stimulate the release of alkaline phosphatase. Cell-mediated functionalization represents an attractive strategy to modify the surface of prosthetic implants with cues of biological relevance, and opens unprecedented possibilities for development of new devices with enhanced therapeutic potential.

National Category
Materials Engineering
Identifiers
urn:nbn:se:uu:diva-333953 (URN)10.1007/s10856-017-5944-1 (DOI)000407947900004 ()28744615 (PubMedID)
Available from: 2017-12-13 Created: 2017-12-13 Last updated: 2018-02-08Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-7356-3002

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