Crystallization of calcium phosphate in polyacrylamide hydrogels containing phosphate ions

Yokoi, Taishi; Kawashita, Masakazu; Kikuta, Koichi; Ohtsuki, Chikara

doi:10.1016/j.jcrysgro.2010.05.028

Cited by 21 publications

(12 citation statements)

References 18 publications

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“…10 Adding an inorganic phase, such as HAp, to a hydrogel is one approach to improve mechanical properties of the biomaterial, although so far the level required for load-bearing applications has not been reached. [11][12][13][14][15][16] However, cell response to mechanical stimuli has gained attention lately and tuning the mechanical properties of a scaffold may hold great potential. 17 It has also been shown that alginate mineralised with HAp improves cell adhesion, and the mineral itself can act as an osteoconductive surface.…”

Section: Introductionmentioning

confidence: 99%

Controlled mineralisation and recrystallisation of brushite within alginate hydrogels

Bjørnøy¹,

Bassett²,

Ucar³

et al. 2016

Biomed. Mater.

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Abstract. Due to high solubility and resorption behaviour under physiological conditions, brushite (CaHPO 4 ·2H 2 O, calcium monohydrogen phosphate dihydrate, dicalcium phosphate dihydrate) has great potential in bone regeneration applications, both in combination with scaffolds or as component of calcium phosphate cements. The use of brushite in combination with hydrogels opens possibilities for new cell based tissue engineering applications of this promising material. However, published preparation methods of brushite composites, in which the mineral phase is precipitated within the hydrogel network, fail to offer the necessary degree of control over mineral phase, content and distribution within the hydrogel matrix. The main focus of this study was to address these shortcomings by determining precise fabrication parameters needed to prepare composites with controlled composition and properties. Composite alginate microbeads were prepared using a counter-diffusion technique which allows for simultaneous crosslinking of the hydrogel and precipitation of an inorganic mineral phase. Reliable nucleation of a desired mineral phase within the alginate network proved more challenging than simple aqueous precipitation. This was largely due to ion transport within the hydrogel producing concentration gradients that modified levels of supersaturation and favoured the nucleation of other phases such as hydroxyapatite and octacalcium phosphate which would otherwise not form. To overcome this, incorporation of brushite seed crystals resulted in good control over the mineral phase and by adjusting the amount of seeds and precursor concentration, the amount of mineral could be tuned. The material has been characterized with a range of physical techniques, including scanning electron microscopy, powder X-ray diffraction and Rietveld refinement, Fourier transform infrared spectroscopy and thermogravimetric analysis, in order to assess mineral morphology, phase and amount within the organic matrix. The mineral content of the composite material converted from brushite into hydroxyapatite when submerged in simulated body fluid, indicating possible bioactivity. Additionally, initial cell culture studies revealed that both the material and the synthesis procedure is compatible with cells relevant to bone tissue engineering.

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Section: Introductionmentioning

confidence: 99%

Controlled mineralisation and recrystallisation of brushite within alginate hydrogels

Bjørnøy¹,

Bassett²,

Ucar³

et al. 2016

Biomed. Mater.

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“…A clear shifting of object distance in focus from around 25-30 to 40 mm can be observed. For IOL applications, it is important to conduct a standard calcification evaluation experiment, typically performed by immersing the PNIPAM gels in a solution of 0.05 -5 mM of calcium nitrate solutions for up to 30 days as reported by Yokoi et al [20].…”

Section: Resultsmentioning

confidence: 99%

A Tunable Morphing Polyelectrolyte System for Smart Ocular Applications

Sun

Sridhar

Chen

et al. 2021

2021 21st International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers)

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For the first time, a focal-length tunable intra-ocular lens (IOL) device has been realized by a standard-shaped, homogeneous "one material" system. Different to existing technologies, this poly(N-isopropylacrylamide) gel (PNIPAM) based polyelectrolyte system doesn't require any additional materials (e.g. metal electrodes, movable mechanical structures) to achieve a controllable lens shape transformation for the focal-length shifting actuation. The designed morphological deformation mechanism employs ionic-strength responsive mechanical buckling via controlled swelling of PNIPAM in phosphate buffered saline (PBS) with similar concentration to human eye liquid. This unique approach will unlock great potential in a wide range of smart ocular applications.

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“…Under these conditions, the Poloxamer 407 forms a gel, which results from packing of the micelles in a cubic phase . The crystal growth in hydrogels have recently been suggested as a new reaction protocol, which provides a unique crystal structure . Poloxamer 407 aqueous solutions in a concentration range of 17.0–40.0 wt% reversibly undergo solution‐to‐gel transition by changing temperature .…”

Section: Resultsmentioning

confidence: 99%

Nanocomposite versus Mesocomposite for Osteogenic Differentiation of Tonsil‐Derived Mesenchymal Stem Cells

Moon

Patel

Chung

et al. 2015

Adv Healthcare Materials

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Injectable inorganic/organic composite systems consisting of well-defined mesocrystals (4-8 μm) of calcium phosphate and polypeptide thermogel significantly enhance the osteogenic differentiation of the tonsil derived mesenchymal stem cells (TMSCs). Compared to composite systems incorporating nanoparticles (10-100 nm) or pure hydrogel systems, osteogenic biomarkers including alkaline phosphatase (ALP), bone morphogenetic protein 2, and osteocalcin are highly expressed at both the mRNA level and the protein level in the mesocrystal composite systems. ALP activity of differentiated cells is also significantly higher in the mesocomposite systems compared to the nanocomposite systems or the pure hydrogel systems. The mesocomposite systems provide not only hard surfaces for binding the cells/proteins by the inorganic mesocrystals but also a soft matrix for holding the cells by the hydrogel. Through the current research, (1) a novel method of preparing mesocrystals is developed, (2) TMSCs are proved as a new resource of stem cells, and (3) the mesocomposite systems are proved to be a promising tool in controlling stem cell differentiation. (4) Finally, the research emphasizes the significance of mesoscience as a new perspective of science in controlling cell and material interfaces.

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Crystallization of calcium phosphate in polyacrylamide hydrogels containing phosphate ions

Cited by 21 publications

References 18 publications

Controlled mineralisation and recrystallisation of brushite within alginate hydrogels

Controlled mineralisation and recrystallisation of brushite within alginate hydrogels

A Tunable Morphing Polyelectrolyte System for Smart Ocular Applications

Nanocomposite versus Mesocomposite for Osteogenic Differentiation of Tonsil‐Derived Mesenchymal Stem Cells

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