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Müller WE, Neufurth M, Tolba E, Wang S, Geurtsen W, Feng Q, Schröder HC, Wang X. A biomimetic approach to ameliorate dental hypersensitivity by amorphous polyphosphate microparticles. Dent Mater 2016; 32:775-83. [DOI: 10.1016/j.dental.2016.03.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 02/10/2016] [Accepted: 03/22/2016] [Indexed: 12/30/2022]
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Wang X, Ackermann M, Wang S, Tolba E, Neufurth M, Feng Q, Schröder HC, Müller WEG. Amorphous polyphosphate/amorphous calcium carbonate implant material with enhanced bone healing efficacy in a critical-size defect in rats. ACTA ACUST UNITED AC 2016; 11:035005. [PMID: 27147677 DOI: 10.1088/1748-6041/11/3/035005] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In this study the effect of amorphous calcium carbonate (ACC) microparticles and amorphous calcium polyphosphate (polyP) microparticles (termed aCa-polyP-MP) on bone mineral forming cells/tissue was investigated in vitro and in vivo. The ACC particles (termed ACC-P10-MP) were prepared in the presence of Na-polyP. Only the combinations of polyP and ACC microparticles enhanced the proliferation rate of human mesenchymal stem cells (MSCs). Gene expression studies revealed that ACC causes an upregulation of the expression of the cell membrane-associated carbonic anhydrase IX (CA IX; formation of ACC), while the transcript level of the alkaline phosphatase (ALP; liberation of orthophosphate from polyP) changes only relatively little. In contrast, aCa-polyP-MP primarily induces ALP expression. If both components are applied together a strong stimulation of expression of both marker genes is observed. In order to investigate whether ACC also enhances bone regeneration induced by polyP in vivo, the particles were encapsulated into PLGA (poly(d,l-lactide-co-glycolide)) microspheres (diameter ~800 μm) and implanted into rat critical-size calvarial defects. The studies revealed that animals that received aCa-polyP-MP microspheres showed an increased rate of regeneration compared to β-tri-calcium phosphate (β-TCP) controls. This effect is even accelerated if microspheres with both aCa-polyP-MP and ACC-P10-MP (1 : 1 weight ratio) are applied, resulting in an almost complete restoration of the defect area after 12 weeks. qRT-PCR analyses of tissue sections through the regeneration zone with microspheres containing both aCa-polyP-MP and ACC-P10-MP revealed a significantly higher upregulation of expression of the marker genes compared to each of the components alone. The Young's moduli for microspheres containing aCa-polyP-MP (1.74 MPa) and aCa-polyP-MP/ACC-P10-MP (2.38 MPa) were markedly higher compared to β-TCP-controls (0.63 mPa). Our results show that the combined application of ACC and Ca-polyP (both in the amorphous state) opens new strategies for the development of regenerative implants for the reconstruction of bone defects.
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Müller WE, Neufurth M, Wang S, Tolba E, Schröder HC, Wang X, Wang X. Morphogenetically active scaffold for osteochondral repair (polyphosphate/alginate/N,O-carboxymethyl chitosan). Eur Cell Mater 2016; 31:174-90. [PMID: 26898843 DOI: 10.22203/ecm.v031a12] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Here we describe a novel bioinspired hydrogel material that can be hardened with calcium ions to yield a scaffold material with viscoelastic properties matching those of cartilage. This material consists of a negatively charged biopolymer triplet, composed of morphogenetically active natural inorganic polyphosphate (polyP), along with the likewise biocompatible natural polymers N,O-carboxymethyl chitosan (N,O-CMC) and alginate. The porosity of the hardened scaffold material obtained after calcium exposure can be adjusted by varying the pre-processing conditions. Various compression tests were applied to determine the local (nanoindentation) and bulk mechanical properties (tensile/compression test system for force measurements) of the N,O-CMC-polyP-alginate material. Determinations of the Young's modulus revealed that the stiffness of this comparably water rich (and mouldable) material increases during successive compression cycles to values measured for native cartilage. The material not only comprises viscoelastic properties suitable for a cartilage substitute material, but also displays morphogenetic activity. It upregulates the expression of genes encoding for collagen type II and aggrecan, the major proteoglycan within the articular cartilage, in human chondrocytes, and the expression of alkaline phosphatase in human bone-like SaOS-2 cells, as revealed in RT qPCR experiments. Further, we demonstrate that the new polyP-based material can be applied for manufacturing 3D solid models of cartilage bone such as of the tibial epiphyseal plate and the superior articular cartilage surface. Since the material is resorbable and enhances the activity of cells involved in regeneration of cartilage tissue, this material has the potential to be used for artificial articular cartilage implants.
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Müller WE, Tolba E, Schröder HC, Muñoz-Espí R, Diehl-Seifert B, Wang X. Amorphous polyphosphate-hydroxyapatite: A morphogenetically active substrate for bone-related SaOS-2 cells in vitro. Acta Biomater 2016; 31:358-367. [PMID: 26654764 DOI: 10.1016/j.actbio.2015.11.060] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/24/2015] [Accepted: 11/29/2015] [Indexed: 12/22/2022]
Abstract
There is increasing evidence that inorganic calcium-polyphosphates (polyP) are involved in human bone hydroxyapatite (HA) formation. Here we investigated the morphology of the particles, containing calcium phosphate (CaP) with different concentrations of various Na-polyP concentrations, as well as their effects in cell culture. We used both SaOS-2 cells and human mesenchymal stem cells. The polymeric phosphate readily binds calcium ions under formation of insoluble precipitates. We found that addition of low concentrations of polyP (<10wt.%, referred to the CaP deposits) results in an increased size of the HA crystals. Surprisingly, at higher polyP concentrations (>10wt.%) the formation of crystalline HA is prevented and amorphous polyP/HA hybrid particles with a size of ≈50nm are formed, most likely consisting of polyP molecules linked via Ca(2+) bridges to the surface of the CaP deposits. Further studies revealed that the polyP-CaP particles cause a strong upregulation of the expression of the genes encoding for two marker proteins of bone formation, collagen type I and alkaline phosphatase. Based on their morphogenetic activity the amorphous polyP-CaP particles offer a promising material for the development of bone implants, formed from physiological inorganic precursors/polymers. STATEMENT OF SIGNIFICANCE Hydroxyapatite (HA) is a naturally occurring mineral of vertebrate bone. Natural HA, a bio-ceramic material which is crystalline to different scale, has been used as a biomaterial to fabricate scaffolds for in situ bone regeneration and other tissue engineering purposes. In contrast to natural HA, synthetic apatite is much less effective. In general, while HA is bioactive, its interaction and biocompatibility with existing bone tissue is low. These properties have been attributed to a minimal degradability in the physiological environment. In the present study we introduce a new Ca-phosphate (CaP) fabrication technology, starting from calcium chloride and dibasic ammonium phosphate with the HA characteristic Ca/P molar ratio of 10:6 and report that after addition >10% (by weight) of polyphosphate (polyP) amorphous CaP/HA samples were obtained. Those samples elicits strong morphogenetic activity let us to conclude that polyP/HA-based material might be beneficial for application as bone substitute implant.
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Wang X, Huang J, Wang K, Neufurth M, Schröder HC, Wang S, Müller WE. The morphogenetically active polymer, inorganic polyphosphate complexed with GdCl 3 , as an inducer of hydroxyapatite formation in vitro. Biochem Pharmacol 2016; 102:97-106. [DOI: 10.1016/j.bcp.2015.12.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 12/14/2015] [Indexed: 12/30/2022]
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Heller M, Bauer HK, Goetze E, Gielisch M, Roth KE, Drees P, Maier GS, Dorweiler B, Ghazy A, Neufurth M, Müller WEG, Schröder HC, Wang X, Vahl CF, Al-Nawas B. Applications of patient-specific 3D printing in medicine. INTERNATIONAL JOURNAL OF COMPUTERIZED DENTISTRY 2016; 19:323-339. [PMID: 28008429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Already three decades ago, the potential of medical 3D printing (3DP) or rapid prototyping for improved patient treatment began to be recognized. Since then, more and more medical indications in different surgical disciplines have been improved by using this new technique. Numerous examples have demonstrated the enormous benefit of 3DP in the medical care of patients by, for example, planning complex surgical interventions preoperatively, reducing implantation steps and anesthesia times, and helping with intraoperative orientation. At the beginning of every individual 3D model, patient-specific data on the basis of computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound data is generated, which is then digitalized and processed using computer-aided design/computer-aided manufacturing (CAD/CAM) software. Finally, the resulting data sets are used to generate 3D-printed models or even implants. There are a variety of different application areas in the various medical fields, eg, drill or positioning templates, or surgical guides in maxillofacial surgery, or patient-specific implants in orthopedics. Furthermore, in vascular surgery it is possible to visualize pathologies such as aortic aneurysms so as to improve the planning of surgical treatment. Although rapid prototyping of individual models and implants is already applied very successfully in regenerative medicine, most of the materials used for 3DP are not yet suitable for implantation in the body. Therefore, it will be necessary in future to develop novel therapy approaches and design new materials in order to completely reconstruct natural tissue.
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Müller WEG, Ackermann M, Tolba E, Neufurth M, Wang S, Schröder HC, Wang X. A bio-imitating approach to fabricate an artificial matrix for cartilage tissue engineering using magnesium-polyphosphate and hyaluronic acid. RSC Adv 2016. [DOI: 10.1039/c6ra17043a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Here we describe an cartilage-like material based on a hyaluronic acid-Mg/Ca-polyphosphate that is fabricated from a water-soluble Na-salt of energy-rich inorganic polyphosphate and soluble hyaluronic acid in the presence of water-insoluble CaCO3.
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Heller M, Bauer HK, Goetze E, Gielisch M, Ozbolat IT, Moncal KK, Rizk E, Seitz H, Gelinsky M, Schröder HC, Wang XH, Müller WEG, Al-Nawas B. Materials and scaffolds in medical 3D printing and bioprinting in the context of bone regeneration. INTERNATIONAL JOURNAL OF COMPUTERIZED DENTISTRY 2016; 19:301-321. [PMID: 28008428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The structural and functional repair of lost bone is still one of the biggest challenges in regenerative medicine. In many cases, autologous bone is used for the reconstruction of bone tissue; however, the availability of autologous material is limited, which always means additional stress to the patient. Due to this, more and more frequently various biocompatible materials are being used instead for bone augmentation. In this context, in order to ensure the structural function of the bone, scaffolds are implanted and fixed into the bone defect, depending on the medical indication. Nevertheless, for the surgeon, every individual clinical condition in which standardized scaffolds have to be aligned is challenging, and in many cases the alignment is not possible without limitations. Therefore, in the last decades, 3D printing (3DP) or additive manufacturing (AM) of scaffolds has become one of the most innovative approaches in surgery to individualize and improve the treatment of patients. Numerous biocompatible materials are available for 3DP, and various printing techniques can be applied, depending on the process conditions of these materials. Besides these conventional printing techniques, another promising approach in the context of medical AM is 3D bioprinting, a technique which makes it possible to print human cells embedded in special carrier substances to generate functional tissues. Even the direct printing into bone defects or lesions becomes possible. 3DP is already improving the treatment of patients, and has the potential to revolutionize regenerative medicine in future.
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Tolba E, Müller WEG, Abd El-Hady BM, Neufurth M, Wurm F, Wang S, Schröder HC, Wang X. High biocompatibility and improved osteogenic potential of amorphous calcium carbonate/vaterite. J Mater Chem B 2015; 4:376-386. [PMID: 32263204 DOI: 10.1039/c5tb02228b] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In human bone, amorphous calcium carbonate (ACC) is formed as a precursor of the crystalline carbonated apatite/hydroxyapatite (HA). Here we describe that the metastable ACC phase can be stabilized by inorganic polyphosphate (polyP) that is also used as a phosphate source for the non-enzymatic carbonate/phosphate exchange during HA formation. This polymer was found to suppress the transformation of ACC into crystalline CaCO3 at a percentage of 5% [w/w] ("CCP5") with respect to CaCO3 and almost completely at 10% [w/w] ("CCP10"). Both preparations (CaCO3/polyP) are amorphous, but also contain small amounts of vaterite, as revealed by XRD, FTIR and SEM analyses. They did not affect the growth/viability of SaOS-2 cells. Cell culture and Ca2+ release experiments revealed that the CaCO3 particles formed in the presence of polyP (CaCO3/polyP) are degradable and, unlike calcite, become disintegrated with time during the cell culture incubation. Again in contrast to calcite, "CCP5" and "CCP10" were found to exhibit osteogenic activity and induce the expression of alkaline phosphatase gene in SaOS-2 cells as well as in human mesenchymal stem cells (MSC). In vivo studies in rats, using PLGA microspheres inserted in the muscles of the back of the animals, revealed that the encapsulated "CCP10" is not only biocompatible but also supports the regeneration at the implant region. We conclude that ACC containing small amounts of vaterite has osteogenic potential and offers superior properties compared to the biologically inert calcite with respect to a potential application as a scaffold material for bone implants.
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Müller WEG, Schröder HC, Tolba E, Diehl-Seifert B, Wang X. Mineralization of bone-related SaOS-2 cells under physiological hypoxic conditions. FEBS J 2015; 283:74-87. [PMID: 26453899 DOI: 10.1111/febs.13552] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 10/01/2015] [Accepted: 10/05/2015] [Indexed: 12/18/2022]
Abstract
Inorganic polyphosphate (polyP) is a physiological energy-rich polymer with multiple phosphoric anhydride bonds. In cells such as bone-forming osteoblasts, glycolysis is the main pathway generating metabolic energy in the form of ATP. In the present study, we show that, under hypoxic culture conditions, the growth/viability of osteoblast-like SaOS-2 cells is not impaired. The addition of polyP to those cells, administered as amorphous calcium polyP nanoparticles (aCa-polyP-NP; approximate size 100 nm), significantly increased the proliferation of the cells. In the presence of polyP, the cells produce significant levels of lactate, the end product of anaerobic glycolysis. Under those conditions, an eight-fold increase in the steady-state level of the membrane-associated carbonic anhydrase IX is found, as well as a six-fold induction of the hypoxia-inducible factor 1. Consequently, biomineral formation onto the SaOS-2 cells decreases under low oxygen tension. If the polyP nanoparticles are added to the cells, the degree of mineralization is enhanced. These changes had been measured also in human mesenchymal stem cells. The assumption that the bicarbonate, generated by the carbonic anhydrase in the presence of polyP under low oxygen, is deposited as a constituent of the bioseeds formed during initial hydroxyapatite formation is corroborated by the identification of carbon besides of calcium, oxygen and phosphorus in the initial biomineral deposit onto the cells using the sensitive technology of high-resolution energy dispersive spectrometry mapping. Based on these data, we conclude that polyP is required for the supply of metabolic energy during bone mineral formation under physiological, hypoxic conditions, acting as a 'metabolic fuel' for the cells to grow.
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Wang X, Schröder HC, Müller WEG. Polyphosphate as a metabolic fuel in Metazoa: A foundational breakthrough invention for biomedical applications. Biotechnol J 2015; 11:11-30. [PMID: 26356505 DOI: 10.1002/biot.201500168] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Revised: 07/24/2015] [Accepted: 08/19/2015] [Indexed: 12/17/2022]
Abstract
In animals, energy-rich molecules like ATP are generated in the intracellular compartment from metabolites, e.g. glucose, taken up by the cells. Recent results revealed that inorganic polyphosphates (polyP) can provide an extracellular system for energy transport and delivery. These polymers of multiple phosphate units, linked by high-energy phosphoanhydride bonds, use blood platelets as transport vehicles to reach their target cells. In this review it is outlined how polyP affects cell metabolism. It is discussed that polyP influences cell activity in a dual way: (i) as a metabolic fuel transferring metabolic energy through the extracellular space; and (ii) as a signaling molecule that amplifies energy/ATP production in mitochondria. Several metabolic pathways are triggered by polyP, among them biomineralization/hydroxyapatite formation onto bone cells. The accumulation of polyP in the platelets allows long-distance transport of the polymer in the extracellular space. The discovery of polyP as metabolic fuel and signaling molecule initiated the development of novel techniques for encapsulation of polyP into nanoparticles. They facilitate cellular uptake of the polymer by receptor-mediated endocytosis and allow the development of novel strategies for therapy of metabolic diseases associated with deviations in energy metabolism or mitochondrial dysfunctions.
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Müller WEG, Tolba E, Schröder HC, Wang X. Back Cover: Macromol. Biosci. 9/2015. Macromol Biosci 2015. [DOI: 10.1002/mabi.201570033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Müller WEG, Tolba E, Schröder HC, Wang X. Polyphosphate: A Morphogenetically Active Implant Material Serving as Metabolic Fuel for Bone Regeneration. Macromol Biosci 2015; 15:1182-1197. [DOI: 10.1002/mabi.201500100] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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Müller WE, Tolba E, Dorweiler B, Schröder HC, Diehl-Seifert B, Wang X. Electrospun bioactive mats enriched with Ca-polyphosphate/retinol nanospheres as potential wound dressing. Biochem Biophys Rep 2015; 3:150-160. [PMID: 29124179 PMCID: PMC5668879 DOI: 10.1016/j.bbrep.2015.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 07/24/2015] [Accepted: 08/07/2015] [Indexed: 11/18/2022] Open
Abstract
Background While electrospun materials have been frequently used in tissue engineering no wound dressings exist that significantly improved wound healing effectively. Methods We succeeded to fabricate three-dimensional (3D) electrospun poly(D,l-lactide) (PLA) fiber mats into which nanospheres, formed from amorphous calcium polyphosphate (polyP) nanoparticles (NP) and encapsulated retinol (“retinol/aCa-polyP-NS” nanospheres [NS]), had been incorporated. Results Experiments with MC3T3-E1 cells revealed that co-incubation of the cells with Ca-polyP together with retinol (or incubation with retinol/aCa-polyP-NS) resulted in a significant synergistic effect on cell growth compared with particle-free polyP complexed with Ca2+ or amorphous Ca-polyP NPs and retinol alone. Incubation of the cells in the presence of the retinol/aCa-polyP NSs also caused a significant increase of the expression levels of the genes encoding for the fatty acid binding protein 4 (FABP4), as well as of the genes encoding for leptin and the leptin receptor. In contrast, the single components, soluble Na-polyP, complexed to Ca2+, or retinol-free aCa-polyP NPs, and retinol, had no significant effect on the expression of these genes. Conclusions These results indicate that the PLA fibers, supplemented with aCa-polyP-NP or retinol/aCa-polyP-NS, elicit morphogenetic activity, suggesting that these fiber mats, along with the antibacterial effect of polyP, have a beneficial potential as wound dressings combining antimicrobial and regenerative (wound healing) properties. General significance The PLA-based fiber mats, containing retinol and polyP nanoparticles, provide promising bioactive meshes that are urgently needed as dressings for chronic wounds. • Effect of PLA fiber mats with polyphosphate/retinol nanospheres on gene expression. • Increased expression of FABP4, leptin and leptin receptor in MC3T3-E1 cells. • Application as wound dressings, combining antimicrobial and regenerative properties.
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Gardères J, Bourguet-Kondracki ML, Hamer B, Batel R, Schröder HC, Müller WEG. Porifera Lectins: Diversity, Physiological Roles and Biotechnological Potential. Mar Drugs 2015; 13:5059-101. [PMID: 26262628 PMCID: PMC4557014 DOI: 10.3390/md13085059] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 07/09/2015] [Accepted: 07/27/2015] [Indexed: 12/29/2022] Open
Abstract
An overview on the diversity of 39 lectins from the phylum Porifera is presented, including 38 lectins, which were identified from the class of demosponges, and one lectin from the class of hexactinellida. Their purification from crude extracts was mainly performed by using affinity chromatography and gel filtration techniques. Other protocols were also developed in order to collect and study sponge lectins, including screening of sponge genomes and expression in heterologous bacterial systems. The characterization of the lectins was performed by Edman degradation or mass spectrometry. Regarding their physiological roles, sponge lectins showed to be involved in morphogenesis and cell interaction, biomineralization and spiculogenesis, as well as host defense mechanisms and potentially in the association between the sponge and its microorganisms. In addition, these lectins exhibited a broad range of bioactivities, including modulation of inflammatory response, antimicrobial and cytotoxic activities, as well as anticancer and neuromodulatory activity. In view of their potential pharmacological applications, sponge lectins constitute promising molecules of biotechnological interest.
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Neufurth M, Wang X, Tolba E, Dorweiler B, Schröder HC, Link T, Diehl-Seifert B, Müller WEG. Modular Small Diameter Vascular Grafts with Bioactive Functionalities. PLoS One 2015; 10:e0133632. [PMID: 26204529 PMCID: PMC4512703 DOI: 10.1371/journal.pone.0133632] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/29/2015] [Indexed: 11/19/2022] Open
Abstract
We report the fabrication of a novel type of artificial small diameter blood vessels, termed biomimetic tissue-engineered blood vessels (bTEBV), with a modular composition. They are composed of a hydrogel scaffold consisting of two negatively charged natural polymers, alginate and a modified chitosan, N,O-carboxymethyl chitosan (N,O-CMC). Into this biologically inert scaffold two biofunctionally active biopolymers are embedded, inorganic polyphosphate (polyP) and silica, as well as gelatin which exposes the cell recognition signal, Arg-Gly-Asp (RGD). These materials can be hardened by exposure to Ca(2+) through formation of Ca(2+) bridges between the polyanions, alginate, N,O-CMC, and polyP (alginate-Ca(2+)-N,O-CMC-polyP). The bTEBV are formed by pressing the hydrogel through an extruder into a hardening solution, containing Ca(2+). In this universal scaffold of the bTEBV biomaterial, polycations such as poly(L-Lys), poly(D-Lys) or a His/Gly-tagged RGD peptide (three RGD units) were incorporated, which promote the adhesion of endothelial cells to the vessel surface. The mechanical properties of the biopolymer material (alginate-Ca(2+)-N,O-CMC-polyP-silica) revealed a hardness (elastic modulus) of 475 kPa even after a short incubation period in CaCl2 solution. The material of the artificial vascular grafts (bTEBVs with an outer size 6 mm and 1.8 mm, and an inner diameter 4 mm and 0.8 mm, respectively) turned out to be durable in 4-week pulsatile flow experiments at an alternating pressure between 25 and 100 mbar (18.7 and 75.0 mm Hg). The burst pressure of the larger (smaller) vessels was 850 mbar (145 mbar). Incorporation of polycationic poly(L-Lys), poly(D-Lys), and especially the His/Gly-tagged RGD peptide, markedly increased the adhesion of human, umbilical vein/vascular endothelial cells, EA.HY926 cells, to the surface of the hydrogel. No significant effect of the polyP samples on the clotting of human plasma is measured. We propose that the metabolically degradable polymeric scaffold bTEBV is a promising biomaterial for future prosthetic vascular grafts.
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Müller WEG, Neufurth M, Huang J, Wang K, Feng Q, Schröder HC, Diehl-Seifert B, Muñoz-Espí R, Wang X. Nonenzymatic Transformation of Amorphous CaCO3into Calcium Phosphate Mineral after Exposure to Sodium Phosphate in Vitro: Implications for in Vivo Hydroxyapatite Bone Formation. Chembiochem 2015; 16:1323-32. [DOI: 10.1002/cbic.201500057] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Indexed: 11/11/2022]
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Müller WEG, Tolba E, Feng Q, Schröder HC, Markl JS, Kokkinopoulou M, Wang X. Amorphous Ca²⁺ polyphosphate nanoparticles regulate the ATP level in bone-like SaOS-2 cells. J Cell Sci 2015; 128:2202-7. [PMID: 25908856 DOI: 10.1242/jcs.170605] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 04/16/2015] [Indexed: 01/08/2023] Open
Abstract
Polyphosphate (polyP) is a physiologically occurring polyanion that is synthesized especially in bone-forming osteoblast cells and blood platelets. We used amorphous polyP nanoparticles, complexed with Ca(2+), that have a globular size of ∼100 nm. Because polyP comprises inorganic orthophosphate units that are linked together through high-energy phosphoanhydride bonds, we questioned whether the observed morphogenetic effect, elicited by polyP, is correlated with the energy-generating machinery within the cells. We show that exposure of SaOS-2 osteoblast-like cells to polyP results in a strong accumulation of mitochondria and a parallel translocation of the polyP-degrading enzyme alkaline phosphatase to the cell surface. If SaOS-2 cells are activated by the mineralization activation cocktail (comprising β-glycerophosphate, ascorbic acid and dexamethasone) and additionally incubated with polyP, a tenfold intracellular increase of the ATP level occurs. Even more, in those cells, an intensified release of ATP into the extracellular space is also seen. We propose and conclude that polyP acts as metabolic fuel after the hydrolytic cleavage of the phosphoanhydride linkages, which contributes to hydroxyapatite formation on the plasma membranes of osteoblasts.
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Müller WEG, Tolba E, Schröder HC, Diehl-Seifert B, Wang X. Retinol encapsulated into amorphous Ca(2+) polyphosphate nanospheres acts synergistically in MC3T3-E1 cells. Eur J Pharm Biopharm 2015; 93:214-23. [PMID: 25900862 DOI: 10.1016/j.ejpb.2015.04.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/06/2015] [Accepted: 04/10/2015] [Indexed: 11/19/2022]
Abstract
Both the quality and quantity of collagen, the major structural component of the skin, decrease in aging skin. We succeeded to encapsulate retinol into amorphous inorganic polyphosphate (polyP) nanoparticles together with calcium ions ("aCa-polyP-NP"), under formation of amorphous Ca-polyP/retinol nanospheres ("retinol/aCa-polyP-NS"). The globular nanospheres are not cytotoxic, show an almost uniform size of ≈ 45 nm and have a retinol content of around 25%. Both components of those nanospheres, retinol and the aCa-polyP-NP, if administered together, caused a strong increase in proliferation of mouse calvaria MC3T3 cells. The expressions of collagen types I, II and III genes, but not the expression of collagen type V gene, were significantly enhanced if retinol is added together with aCa-polyP-NP. This synergistic effect was especially pronounced for the expression of the collagen type III gene. We propose that the synergistic effect of the retinol/aCa-polyP-NS on cell growth and collagen type III expression is induced via two routes, first through cellular uptake of the 45 nm nanospheres by clathrin-mediated endocytosis and second through extracellular disintegration of the nanospheres resulting in the release of retinol which is then taken up into the cells after binding to the retinal binding protein receptor.
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Müller WEG, Tolba E, Schröder HC, Wang S, Glasser G, Diehl-Seifert B, Wang X. Biologizing titanium alloy implant material with morphogenetically active polyphosphate. RSC Adv 2015. [DOI: 10.1039/c5ra14240g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
As a further step towards a new generation of bone implant materials, we developed a procedure for biological functionalization of titanium alloy surfaces with inorganic calcium polyphosphate (Ca-polyP).
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Li Q, Wang X, Korzhev M, Schröder HC, Link T, Tahir MN, Diehl-Seifert B, Müller WE. Potential biological role of laccase from the sponge Suberites domuncula as an antibacterial defense component. Biochim Biophys Acta Gen Subj 2015; 1850:118-28. [DOI: 10.1016/j.bbagen.2014.10.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 10/07/2014] [Accepted: 10/08/2014] [Indexed: 02/08/2023]
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Müller WEG, Tolba E, Schröder HC, Neufurth M, Wang S, Link T, Al-Nawas B, Wang X. A new printable and durable N,O-carboxymethyl chitosan–Ca2+–polyphosphate complex with morphogenetic activity. J Mater Chem B 2015; 3:1722-1730. [DOI: 10.1039/c4tb01586j] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In the absence of Ca2+ the polymers N,O-carboxymethyl chitosan, together with Na-polyphosphate and alginate, form random-coiled structures. Addition of Ca2+ transforms these polymers to durable implants.
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Wang X, Tolba E, Schröder HC, Neufurth M, Feng Q, Diehl-Seifert B, Müller WEG. Effect of bioglass on growth and biomineralization of SaOS-2 cells in hydrogel after 3D cell bioprinting. PLoS One 2014; 9:e112497. [PMID: 25383549 PMCID: PMC4226565 DOI: 10.1371/journal.pone.0112497] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 10/15/2014] [Indexed: 12/16/2022] Open
Abstract
We investigated the effect of bioglass (bioactive glass) on growth and mineralization of bone-related SaOS-2 cells, encapsulated into a printable and biodegradable alginate/gelatine hydrogel. The hydrogel was supplemented either with polyphosphate (polyP), administered as polyP • Ca2+-complex, or silica, or as biosilica that had been enzymatically prepared from ortho-silicate by silicatein. These hydrogels, together with SaOS-2 cells, were bioprinted to computer-designed scaffolds. The results revealed that bioglass (nano)particles, with a size of 55 nm and a molar ratio of SiO2 : CaO : P2O5 of 55 : 40 : 5, did not affect the growth of the encapsulated cells. If silica, biosilica, or polyP • Ca2+-complex is co-added to the cell-containing alginate/gelatin hydrogel the growth behavior of the cells is not changed. Addition of 5 mg/ml of bioglass particles to this hydrogel significantly enhanced the potency of the entrapped SaOS-2 cells to mineralize. If compared with the extent of the cells to form mineral deposits in the absence of bioglass, the cells exposed to bioglass together with 100 µmoles/L polyP • Ca2+-complex increased their mineralization activity from 2.1- to 3.9-fold, or with 50 µmoles/L silica from 1.8- to 2.9-fold, or with 50 µmoles/L biosilica from 2.7- to 4.8-fold or with the two components together (100 µmoles/L polyP • Ca2+-complex and 50 µmoles/L biosilica) from 4.1- to 6.8-fold. Element analysis by EDX spectrometry of the mineral nodules formed by SaOS-2 revealed an accumulation of O, P, Ca and C, indicating that the mineral deposits contain, besides Ca-phosphate also Ca-carbonate. The results show that bioglass added to alginate/gelatin hydrogel increases the proliferation and mineralization of bioprinted SaOS-2 cells. We conclude that the development of cell-containing scaffolds consisting of a bioprintable, solid and cell-compatible inner matrix surrounded by a printable hard and flexible outer matrix containing bioglass, provide a suitable strategy for the fabrication of morphogenetically active and biodegradable implants.
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Wang S, Wang X, Draenert FG, Albert O, Schröder HC, Mailänder V, Mitov G, Müller WEG. Bioactive and biodegradable silica biomaterial for bone regeneration. Bone 2014; 67:292-304. [PMID: 25088401 DOI: 10.1016/j.bone.2014.07.025] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/19/2014] [Accepted: 07/22/2014] [Indexed: 02/01/2023]
Abstract
Biosilica, a biocompatible, natural inorganic polymer that is formed by an enzymatic, silicatein-mediated reaction in siliceous sponges to build up their inorganic skeleton, has been shown to be morphogenetically active and to induce mineralization of human osteoblast-like cells (SaOS-2) in vitro. In the present study, we prepared beads (microspheres) by encapsulation of β-tricalcium phosphate [β-TCP], either alone (control) or supplemented with silica or silicatein, into the biodegradable copolymer poly(d,l-lactide-co-glycolide) [PLGA]. Under the conditions used, ≈5% β-TCP, ≈9% silica, and 0.32μg/mg of silicatein were entrapped into the PLGA microspheres (diameter≈800μm). Determination of the biocompatibility of the β-TCP microspheres, supplemented with silica or silicatein, revealed no toxicity in the MTT based cell viability assay using SaOS-2 cells. The adherence of SaOS-2 cells to the surface of silica-containing microspheres was higher than for microspheres, containing only β-TCP. In addition, the silica-containing β-TCP microspheres and even more pronounced, a 1:1 mixture of microspheres containing β-TCP and silica, and β-TCP and silicatein, were found to strongly enhance the mineral deposition by SaOS-2 cells. Using these microspheres, first animal experiments with silica/biosilica were performed in female, adult New Zealand White rabbits to study the effect of the inorganic polymer on bone regeneration in vivo. The microspheres were implanted into 5mm thick holes, drilled into the femur of the animals, applying a bilateral comparison study design (3 test groups with 4-8 animals each). The control implant on one of the two hind legs contained microspheres with only β-TCP, while the test implant on the corresponding leg consisted either of microspheres containing β-TCP and silica, or a 1:1 mixture of microspheres, supplemented with β-TCP and silica, and β-TCP and silicatein. The results revealed that tissue/bone sections of silica containing implants and implants, composed of a 1:1 mixture of silica-containing microspheres and silicatein-containing microspheres, show an enhanced regeneration of bone tissue around the microspheres, compared to the control implants containing only β-TCP. The formation of new bone induced by the microspheres is also evident from measurements of the stiffness/reduced Young's modulus of the regenerated bone tissue. The reduced Young's modulus of the regenerating bone tissue around the implants was markedly higher for the silica-containing microspheres (1.1MPa), and even more for the 1:1 mixture of the silica- and silicatein-containing microspheres (1.4MPa), compared to the β-TCP microsphere controls (0.4MPa). We propose that based on their morphogenetic activity on bone-forming cells in vitro and the results of the animal experiments presented here, silica/biosilica-based scaffolds are promising materials for bone repair/regeneration.
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Müller WE, Tolba E, Schröder HC, Diehl-Seifert B, Link T, Wang X. Biosilica-loaded poly(ϵ-caprolactone) nanofibers mats provide a morphogenetically active surface scaffold for the growth and mineralization of the osteoclast-related SaOS-2 cells. Biotechnol J 2014; 9:1312-21. [DOI: 10.1002/biot.201400277] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 05/31/2014] [Accepted: 06/30/2014] [Indexed: 11/07/2022]
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