“…10 The reason may be attributed to two factors, one is that l -lysine contains more active amino groups than KH550, and another may be contributed to the formation of Ca carboxylate originated from l -lysine and n-HA, which would improve the dispersion of n-HA before grafting. 17 Accordingly, the more l -lysine is more useful to increase the grafting amount onto n-HA, which would be benefit to improve the dispersion of n-HA. Figure 3.TGA curves and photographs of (a) n-HA, (b) g1-n-HA, and (c) g2-n-HA dispersed in dichloromethane for different times.…”
It is promising and challenging to study surface modification for nano-hydroxyapatite to improve the dispersion and enhance the mechanical properties and bioactivity of poly(lactic acid-co-glycolic acid). In this paper, we designed an effective new surface grafting with the assist of l-lysine for nano-hydroxyapatite, and the nano-hydroxyapatite surface grafted with the assist of l-lysine (g-nano-hydroxyapatite) was incorporated into poly(lactic acid-co-glycolic acid) to develop a series of g-nano-hydroxyapatite/poly(lactic acid-co-glycolic acid) nano-composites. The surface modification reaction for nano-hydroxyapatite, the mechanical properties, and in vitro human osteoblast-like cell (MG-63) response were characterized and investigated by Fourier transformation infrared, thermal gravimetric analysis, dispersion test, electromechanical universal tester, differential scanning calorimeter measurements, and in vitro cells culture experiment. The results showed that the grafting amount on the surface of nano-hydroxyapatite was enhanced with the increase of l-lysine, and the dispersion of nano-hydroxyapatite was improved more, so that it brought about better promotion crystallization and more excellent mechanical enhancement effect for poly(lactic acid-co-glycolic acid), comparing with the unmodified nano-hydroxyapatite. Moreover, the cells' attachment and proliferation results confirmed that the incorporation of the g-nano-hydroxyapatite into poly(lactic acid-co-glycolic acid) exhibited better biocompatibility than poly(lactic acid-co-glycolic acid). The above results indicated that the new surface grafting with the assist of l-lysine for nano-hydroxyapatite was an ideal novel surface modification method, which brought about better mechanical enhancement effect and in vitro bioactivity for poly(lactic acid-co-glycolic acid) with adding higher g-nano-hydroxyapatite content, suggesting it had a great potential to be used as bone fracture internal fixation materials in future.
“…10 The reason may be attributed to two factors, one is that l -lysine contains more active amino groups than KH550, and another may be contributed to the formation of Ca carboxylate originated from l -lysine and n-HA, which would improve the dispersion of n-HA before grafting. 17 Accordingly, the more l -lysine is more useful to increase the grafting amount onto n-HA, which would be benefit to improve the dispersion of n-HA. Figure 3.TGA curves and photographs of (a) n-HA, (b) g1-n-HA, and (c) g2-n-HA dispersed in dichloromethane for different times.…”
It is promising and challenging to study surface modification for nano-hydroxyapatite to improve the dispersion and enhance the mechanical properties and bioactivity of poly(lactic acid-co-glycolic acid). In this paper, we designed an effective new surface grafting with the assist of l-lysine for nano-hydroxyapatite, and the nano-hydroxyapatite surface grafted with the assist of l-lysine (g-nano-hydroxyapatite) was incorporated into poly(lactic acid-co-glycolic acid) to develop a series of g-nano-hydroxyapatite/poly(lactic acid-co-glycolic acid) nano-composites. The surface modification reaction for nano-hydroxyapatite, the mechanical properties, and in vitro human osteoblast-like cell (MG-63) response were characterized and investigated by Fourier transformation infrared, thermal gravimetric analysis, dispersion test, electromechanical universal tester, differential scanning calorimeter measurements, and in vitro cells culture experiment. The results showed that the grafting amount on the surface of nano-hydroxyapatite was enhanced with the increase of l-lysine, and the dispersion of nano-hydroxyapatite was improved more, so that it brought about better promotion crystallization and more excellent mechanical enhancement effect for poly(lactic acid-co-glycolic acid), comparing with the unmodified nano-hydroxyapatite. Moreover, the cells' attachment and proliferation results confirmed that the incorporation of the g-nano-hydroxyapatite into poly(lactic acid-co-glycolic acid) exhibited better biocompatibility than poly(lactic acid-co-glycolic acid). The above results indicated that the new surface grafting with the assist of l-lysine for nano-hydroxyapatite was an ideal novel surface modification method, which brought about better mechanical enhancement effect and in vitro bioactivity for poly(lactic acid-co-glycolic acid) with adding higher g-nano-hydroxyapatite content, suggesting it had a great potential to be used as bone fracture internal fixation materials in future.
“…For several years, we have conducting research on the effect of dispersion medium [18,19] and ultrasound [20] on the size dis tribution of nanoparticles and submicroparticles in aqueous HA suspensions. We found the conditions for stabilizing suspensions containing HA nano and/or submicroparticles.…”
Section: A Capillary Zone Electrophoresis Study Of the Effect Of Precmentioning
A set of analytical techniques is proposed for studying samples of calcium hydroxyapatite (HA) synthesized on the basis of calcium nitrate or calcium hydroxide as precursors. A comparative study of parti cle size distribution in HA samples is performed using capillary zone electrophoresis (CZE), scanning elec tron microscopy (SEM), dynamic light scattering (DS), and static light scattering (SS). The effect of heat treatment on the morphology of the synthesized products is evaluated. It is found that the effect of ultrasound (US) on the dispersity of HA particles in aqueous suspensions depends on the nature of the precursor and heat treatment. It is shown that the HA particles synthesized from calcium hydroxide (HA-OH) aggregate more rapidly than the particles synthesized from calcium nitrate (HA-NO 3 ). After the ultrasonic treatment of sus pensions, the relative concentration of large HA-NO 3 submicroparticles increased, while particle size distri bution in the suspension of HA-OH remained virtually the same. The heat treatment of HA powders at 900°C reduced the ability of particles to aggregate. It is found by CZE that, with increasing time of ultrason ication of suspensions, the relative concentration of nanoscaled and similar in size HA-NO 3 submicroparti cles increased markedly, while it changed only slightly in the HA-OH suspension. The reasons for the differ ences are discussed. A procedure for determining the concentration of HA submicroparticles in suspension by CZE is proposed. A linear dependence of normalized peak areas on HA concentration in suspension is obtained.
“…Chemical compositions, dimensions, morphologies, optical and other properties of these nanoparticles can be easily regulated by the plasma discharge parameters, materials of electrodes and liquids. In other works, it was demonstrated that ultrasonic cavitation itself is a promising way for modification of properties of solid nano-and microparticles [9][10][11][12][13][14][15][16].…”
Section: Synthesis Of Nanoparticles In Plasma Discharge In a Cavitating Liquidmentioning
In this study, plasma discharge in a liquid at intensive ultrasonic field above the cavitation threshold has been proven to be of great interest for initiation of various physical and chemical processes. In such discharge, nanoparticles of tungsten and zinc oxides have been synthesized. Further exploration of synthesized nanoparticles has demonstrated that the factor of ultrasonic cavitation during the synthesis substantially affects physical and chemical characteristics of nanoparticles.
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