Combined Hydrothermal Conversion and Vapor Transport Sintering of Ag‐Modified Calcium Phosphate Scaffolds

Schlosser, Margarete; Fröls, Sabrina; Hauf, U.; Sethmann, Ingo; Schultheiss, Sigrid; Pfeifer, Felicitas; Kleebe, Hans‐Joachim

doi:10.1111/jace.12137

Cited by 10 publications

(19 citation statements)

References 51 publications

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“…2 Moreover, the absorption peaks at 873, 1420, and 1460 cm À1 are also detected that indicate incorporation of CO 3 2À groups into HAp lattice structure through the B-type substitution. 13 The substitution maybe come from small amount of carbonate impurities in the raw materials. Figure 2 exhibits the SEM images of the HAp microspherical material.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of Hydroxyapatite Hollow Microspheres by the Composite‐Hydroxide Approach

Chen

et al. 2014

J. Am. Ceram. Soc.

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Hydroxyapatite (HAp) hollow microspheres with hierarchically porous structure and nanorice‐like architecture units were synthesized by the composite‐hydroxide approach. NH4H2PO4 was first reacted with hydroxides to form a hydroxide‐insoluble M3PO4 (the term M represents either Na or K). The diffusing M3PO4 at the liquid–solid interface then reacted with the Ca(OH)2, forming insoluble HAp hollow spheres by Kirkendall process. Results show that when reaction time is increased from 3 to 12 h, the average diameter of the microspheres increased from 2.64 to 4.16 μm. In addition, the size homogeneity of the hollow microspheres was improved gradually due to Ostwald ripening. The prepared hollow microspheres were treated by ultrasound, and nanorice‐like component units with a large mass of mesopores (<10 nm) were displayed. These prepared HAp hollow microspheres might be expected to apply to ion adsorption and drug delivery.

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Section: Resultsmentioning

confidence: 99%

Fabrication of Hydroxyapatite Hollow Microspheres by the Composite‐Hydroxide Approach

Chen

et al. 2014

J. Am. Ceram. Soc.

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“…The zone of inhibition was measured as the maximum distance from the PAA-silver nanofiber scaffold in a number of directions at which an inhibition of bacterial growth was observed. This approach was already chosen in earlier studies [32,33]. These results showed that Silver NPs had multiple inhibitory actions for the interruption and blockage of activity against fungal and bacterial strains, which will minimize expenses required for disease control.…”

Section: Antimicrobial Activitymentioning

confidence: 94%

Antimicrobial Activity of Silver Containing Crosslinked Poly(Acrylic Acid) Fibers

et al. 2019

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Bacterial and fungal pathogens have caused serious problems to the human health. This is particularly true for untreatable infectious diseases and clinical situations where there is no reliable treatment for infected patients. To increase the antimicrobial activity of materials, we introduce silver nanoparticle (NP) patches in which the NPs are incorporated to the surface of smooth and uniform poly(acrylic acid) (PAA) nanofibers. The PAA nanofibers were thermally crosslinked with ethylene glycol via heat treatment through a mild method. The characterization of the resulting PAA-silver NP patches was done using scanning electron microscopy (SEM), UV spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). To demonstrate the antimicrobial activity of PAA, we incorporated the patches containing the silver NPs into strains of fungi such as Candida albicans (C. albican) and bacteria such as Methicillin-resistant Staphylococcus aureus (MRSA). The PAA-silver fibers achieved zones of inhibition against C. albicans and MRSA indicating their antimicrobial activity against both fungi and bacteria. We conclude that silver NP patches exhibited multiple inhibitory actions for the interruption and blockage of activity fungal and bacterial strains, which has the potential as an antimicrobial agent in infectious diseases. Moreover, the proposed material has the potential to be used in antimicrobial textile fabrics, food packaging films, and wound dressings.

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“…Pseudomorphic conversion of biocarbonate in contact with phosphate-bearing solutions takes place via interface coupled dissolution-recrystallization [16,22,33,34]. The conversion mechanism involves the dissolution of primary aragonite and the precipitation of secondary apatite [35][36][37][38][39][40].…”

Section: The Phase Conversion Mechanismmentioning

confidence: 99%

“…Consequently, the newly formed product layer commonly contains a certain amount of intrinsic intergranular porosity and does not seal completely the parent phase from further interaction with the solution [46,47]. In addition, the molar volume change associated with the aragonite-AP conversion is negative (−6%) [16,22,34]. As the external shape of the sample is preserved during conversion, porosity has to be generated to compensate the molar volume loss [35][36][37][38][39][40].…”

Section: The Conversion Of Geologic Aragonitementioning

confidence: 99%

Biomineral Reactivity: The Kinetics of the Replacement Reaction of Biological Aragonite to Apatite

et al. 2018

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Abstract:We present results of bioaragonite to apatite conversion in bivalve, coral and cuttlebone skeletons, biological hard materials distinguished by specific microstructures, skeletal densities, original porosities and biopolymer contents. The most profound conversion occurs in the cuttlebone of the cephalopod Sepia officinalis, the least effect is observed for the nacreous shell portion of the bivalve Hyriopsis cumingii. The shell of the bivalve Arctica islandica consists of cross-lamellar aragonite, is dense at its innermost and porous at the seaward pointing shell layers. Increased porosity facilitates infiltration of the reaction fluid and renders large surface areas for the dissolution of aragonite and conversion to apatite. Skeletal microstructures of the coral Porites sp. and prismatic H. cumingii allow considerable conversion to apatite. Even though the surface area in Porites sp. is significantly larger in comparison to that of prismatic H. cumingii, the coral skeleton consists of clusters of dense, acicular aragonite. Conversion in the latter is sluggish at first as most apatite precipitates only onto its surface area. However, the process is accelerated when, in addition, fluids enter the hard tissue at centers of calcification. The prismatic shell portion of H. cumingii is readily transformed to apatite as we find here an increased porosity between prisms as well as within the membranes encasing the prisms. In conclusion, we observe distinct differences in bioaragonite to apatite conversion rates and kinetics depending on the feasibility of the reaction fluid to access aragonite crystallites. The latter is dependent on the content of biopolymers within the hard tissue, their feasibility to be decomposed, the extent of newly formed mineral surface area and the specific biogenic ultra-and microstructures.

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Combined Hydrothermal Conversion and Vapor Transport Sintering of Ag‐Modified Calcium Phosphate Scaffolds

Cited by 10 publications

References 51 publications

Fabrication of Hydroxyapatite Hollow Microspheres by the Composite‐Hydroxide Approach

Fabrication of Hydroxyapatite Hollow Microspheres by the Composite‐Hydroxide Approach

Antimicrobial Activity of Silver Containing Crosslinked Poly(Acrylic Acid) Fibers

Biomineral Reactivity: The Kinetics of the Replacement Reaction of Biological Aragonite to Apatite

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