Morphology of colloidal metal pyrophosphate salts

Leeuwen, Y. Mikal van; Velikov, Krassimir P.; Kegel, Willem K.

doi:10.1039/c2ra00449f

Cited by 28 publications

(50 citation statements)

References 34 publications

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“…Increasing concentrations formed a greater amount of precipitant, with an approximate yield of 0.5 mg/mL at 1mM and 0.01 mg/mL at 100μM in alpha MEM. SEM images of the dried precipitant ( Fig 1A ) reveal a spherical/ amorphous morphology, ranging from 50 to 100nm in diameter, similar to what has been reported by Gras and Leeuwin et al [ 17 , 34 ]. The XRD spectra ( Fig 1B ) confirms an amorphous composition, with a broad peak at 30°.…”

Section: Resultssupporting

confidence: 85%

“…The physical properties of calcium pyrophosphate, such as solubility, particle size, uptake or hydrolysis rate are also important variables that can vary depending on the synthesis, purification, sterilization and storage conditions [ 4 , 15 , 21 ]. The sterilization process of autoclaving and even the commonly used dispersion process of ultrasonication, can alter the crystal structure of amorphous calcium pyrophosphate towards monoclinic and triclinic-like crystals [ 17 , 34 ]. It is, therefore, important to characterize the exact form of pyrophosphate used in cellular testing.…”

Section: Discussionmentioning

confidence: 99%

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Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

Pujari-Palmer

et al. 2016

PLoS ONE

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Pyrophosphate is a potent mitogen, capable of stimulating proliferation in multiple cell types, and a critical participant in bone mineralization. Pyrophosphate can also affect the resorption rate and bioactivity of orthopedic ceramics. The present study investigated whether calcium pyrophosphate affected proliferation, differentiation and gene expression in early (MC3T3 pre-osteoblast) and late stage (SAOS-2 osteosarcoma) osteoblasts. Pyrophosphate stimulated peak alkaline phosphatase activity by 50% and 150% at 100μM and 0.1μM in MC3T3, and by 40% in SAOS-2. The expression of differentiation markers collagen 1 (COL1), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) were increased by an average of 1.5, 2, 2 and 3 fold, by high concentrations of sodium pyrophosphate (100μM) after 7 days of exposure in MC3T3. COX-2 and ANK expression did not differ significantly from controls in either treatment group. Though both high and low concentrations of pyrophosphate stimulate ALP activity, only high concentrations (100μM) stimulated osteogenic gene expression. Pyrophosphate did not affect proliferation in either cell type. The results of this study confirm that chronic exposure to pyrophosphate exerts a physiological effect upon osteoblast differentiation and ALP activity, specifically by stimulating osteoblast differentiation markers and extracellular matrix gene expression.

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Section: Resultssupporting

confidence: 85%

Section: Discussionmentioning

confidence: 99%

Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

Pujari-Palmer

et al. 2016

PLoS ONE

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“…[28][29][30][31][32][33][34] Therefore, they have been received considerable attention and some progress has been made. [35][36][37][38][39][40][41][42] A preparation process has been used to synthesize an array of transition-metal phosphate amorphous colloidal spheres by Li et al [ 28 ] Since Attfi ed and co-workers fi rst reported the synthesis of M 11 (HPO 3 ) 8 (OH) 6 (M = Zn, Co, and Ni) in 1993, [ 33,34 ] these transition metal phosphites have attracted intense interest because of their microporous structures and novel potential catalytic, electrical, optical, and magnetic properties. [43][44][45][46] Meanwhile, the shape and size of inorganic materials have also been regarded as critical factors in varying their electrical, optical, and other properties.…”

Section: Introductionmentioning

confidence: 99%

The Morphology Evolution of Nickel Phosphite Hexagonal Polyhedrons and Their Primary Electrochemical Capacitor Applications

Pang

Zhang

Wei

et al. 2013

Part & Part Syst Charact

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Nickel posphite (Ni11(HPO3)8(OH)6) hexagonal polyhedrons are successfully synthesized under hydrothermal conditions. The effect of surfactants on the growth mechanism of Ni11(HPO3)8(OH)6 are also explored. More importantly, Ni11(HPO3)8(OH)6 hexagonal polyhedrons are successfully applied as electrochemical supercapacitor electrode materials, which have a good specific capacitance (295 F g−1 at 0.625 A g−1), good rate capability, and cycling properties (maintained about 99.3% at 0.625 A g−1 after 1000 cycles).

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“…8,9,16 This unexpected repeptization of iron pyrophosphate is likely caused by the amorphous nature and open structure of the precipitate, which is observed independent of the preparation method. 17 During coprecipitation of FePP i , the 5−20 nm particles immediately form ∼200 nm clusters that slowly aggregate further until they are macroscopically large. We have proposed that this slow further growth occurs by connecting the smaller, 5 nm particles that have a lower stabilizing barrier.…”

Section: ■ Resultsmentioning

confidence: 99%

“…Unfortunately, because of the small size of the particles and the beamsensitivity of the material, 17 we have yet to find a suitable technique to analyze this. The only preparation route that leads to systems still stable after one year (high salt Na + dialyzed for 3 days).…”

Section: ■ Resultsmentioning

confidence: 99%

Repeptization by Dissolution in a Colloidal System of Iron(III) Pyrophosphate

2012

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Repeptization (redispersion) from an aggregated state is usually only possible in charge-stabilized colloidal systems if the system is either coagulated in the secondary minimum of the interaction potential or if the system cannot settle completely into the primary minimum. In this work, we analyze the zeta potential, conductivity, and long-term stability of colloidal systems of iron(III) pyrophosphate and surprisingly find that the system seems to defy conventional wisdom as it can be repeptized from its coagulated state regardless of aging time and background ions. Moreover, after having been stored for up to a month in 2 M NaCl, dialysis of iron pyrophosphate will yield a colloidal dispersion that is actually stable for a longer period of time than a fresh system with background electrolyte removed. ■ INTRODUCTIONDestabilization and coagulation in the primary minimum of the interaction potential occurs when colliding particles overcome the repulsion and cross the stabilizing barrier; see Figure 1. Once trapped, lowering the ionic strength will only repeptize (redisperse) the particles if there is a distance of closest approach (or cutoff distance) between the particles, otherwise repeptization from the deep primary minimum will be impossible. 1 A possible cause for such a cutoff distance in an electrocratic (charge-stabilized) system arises if interparticle interactions during a Brownian collision occur under constant surface charge instead of constant surface potential, as the reequilibration needed for a constant potential takes place in a timespan orders of magnitude larger than that of the collisions. This implies that the cutoff distance will vanish over time with equilibration, explaining why aged systems cannot be repeptized as is indeed often observed. 2,3 Other possible causes for a cutoff distance include surface roughness and the presence of the hydration layer itself, but these will also vanish over time by re-equilibration or sintering. 1,4−6 Note that we are working with a system that contains no stabilizing agents such as surfactants or polymers, making steric stabilization (another common cause for a distance of closest approach) highly unlikely.While repeptization is important from a practical viewpoint as it governs the ability for colloidal dispersions to be dried, stored, and redispersed, it is almost exclusively studied when going from the dried to the dispersed state, 4,7 comprising only a minor part of the phenomenon. However, current literature agrees that while repeptization from the primary minimum can be experimentally realized when coagulation is induced by monovalent background ions and short aging times, the repeptization of systems aggregated by polyvalent ions is not possible by simply lowering the ionic strength of the medium: it needs additional means such as addition of surfactants 8 or Received: September 12, 2012 Revised: November 13, 2012 Published: November 14, 2012 Figure 1. Schematic representations of interparticle interaction potentials in an electrocratic ...

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Morphology of colloidal metal pyrophosphate salts

Cited by 28 publications

References 34 publications

Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

The Morphology Evolution of Nickel Phosphite Hexagonal Polyhedrons and Their Primary Electrochemical Capacitor Applications

Repeptization by Dissolution in a Colloidal System of Iron(III) Pyrophosphate

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