Abstract: The objective of this study was to evaluate the in vivo characteristics of poly (ethylene glycol)-poly (lacticacid-co-glycolicacid)-poly (ethylene- glycol) (PELGE) copolymers as drug carriers. In order to test this circulation time, mitoxantrone (DHAQ) was used as a model drug in this study. DHAQ
nanoparticles (DHAQ-NP) were prepared, subsequently the DHAQ-NP were evaluated by measuring the drug concentration in plasma after intravenous administration via the tail vein of mice. The circulation time of the DHAQ-NP were tested. The results showed prolonged mitoxantrone (DHAQ) residence in systemic blood circulation.
Abstract: Surface topography was believed to be a factor affecting cellular morphology, proliferation, and differentiation. In present work, we examined the facts that nanogrooved surfaces had an effect on the attachment and alignment behavior of C6 cells in detail. The nanogrooves on the surface were fabricated by Laser-induced periodic structures (LIPS) technique (Polarized laser:λ=266nm). The parallel grooves and ridges on the polystyrene were 300-350nm in period and 40-50nm in depth. In addition, we also tried to control cells growth via surface nanostructures on the patterns. And then we evaluated the attachment and alignment of C6 cells on these substrates. After 2 days of incubation, we found that C6 cells were elongated and aligned along patterns of grooves and ridges, whereas were mostly random on smooth substrates. By observing, the response of cells to nano-sized feature suggested that the formation of fibrous cellular components, especially in the filopodium and lamellipodia, were influenced by the nanogrooves. These findings would have potential applications in tissue engineering and in the design of biosensors.
Abstract: Titania ceramics is lack of bone-bonding ability even if it has excellent biocompatibility. Recently, it is even found that the nanophase titania ceramics could enhance the proliferation of osteoblasts. If the bone-bonding ability of this material is improved, it would be a potential bone replacement material. Bioactive glass-ceramic (BGC) is provided with the best bioactivity in biomaterials. In this study, the apatite formation ability and the mechanic properties of titania ceramic were investigated by the accession of BGC. Four samples: TiO2 ceramic, TiO2 +10%BGC, TiO2 +20%BGC and BGC were prepared respectively. These ceramics were exposed to a simulated body fluid (SBF) for 7, 14 and 21d. Scanning electron microscopy (SEM), energy dispersive X-ray detector (EDX) and thin film X-ray diffraction (TF-XRD) results showed that the apatite formation of the ceramics was improved by adding BGC into nanophase titania ceramic. The mechanical analysis showed the biomechanical compatibility was also improved by adding BGC into nanophase titania ceramic.
Abstract: The bioactive nanoparticles in the system CaO-P2O5-SiO2 were synthesized via
microemulsions method in this study. The structure and properties of the nanoparticles were investigated in details using XRD, TEM, FTIR, BET techniques. It was found that, in a stable phase W/O emulsions, the diameter of the nanoparticles were related to the molar ratio of water to surfactant (γ). Under the favorable conditions, i.e. γ=6, nano-sized spherical amorphous particles could be obtained with the average diameter of 25 nm. The microemulsions could be an alternative method to prepare bioactive nanoparticles for bone reparation and bone tissue engineering scaffolds.
Abstract: Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) is biocompatible and bioactive, however, it is relatively brittle. The development of HAp coatings on medical metal surface is a good way to improve the mechanical properties of HAp. In the present study, a HAp coating with nano-structure on a roughened titanium surface was developed by electrophoretic deposition process. To decrease sintering temperature HAp nanoparticles synthesized by a wet chemical method was used. It was observed that the coating was uniform and showed no cracks. After sintering the HAp coating still remained nano structured. The surface treatment of Ti was applied to form a distribution of small pits and a TiO2 thin layer on the Ti surface that improves the adhesion of coating to the Ti substrate. It was shown that the bonding strength of coating was 18 ± 2.5MPa. The hardness and Young’s modulus were 40.6 and 0.42 GPa, respectively.
Abstract: The HA nanobelts had been synthesized by using surfactants. It possesses a uniform one-dimensional nanofibers with width in 1.37nm and a BET specific surface area of 85.2m2g-1. The 31P NMR spectrum showed three –0.59ppm,-1.76ppm,-3.22ppm followed by a series of identical sidebands and one weak peak at –4.69ppm . The FTIR spectra of the nanobelts included two types of vibration; three PO4 3- stretching modes at 939.1,1030.4 and 1100.0cm-1 band were attributed to the ν1(PO4), ν3(PO4), ν3(PO4) modes respectively. Two PO4 3- bending modes at 569.6 and 608.7cm-1 bands were attributed to the ν4(PO4) modes .The
bands observed around 473.9cm-1 were attributed toν2(PO4) modes. The nanobelts were novel drug carries.
Abstract: Nanocomposites of hydroxyapatite-fibroin (HA-FB) were prepared using the biomimetic process. The Nanocomposites were detected with X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The FTIR results showed that chemical bond forms between HA nanocrystals and fibroin protein. The secondary structure of fibroin can be affected by the mineralization process. TGA results indicated the content of mineralized fibroin in the nanocomposites can be freely adjusted by changing the initial concentration of fibroin solution. TEM image showed that the diameter of the single mineralized nanofibrils is about 2-3 nm and the nanofibrils can aggregate into bundles with the size of 6-8 nm in width and 30-60 nm in length.
Abstract: A nano-grade hydroxyapatite/collagen composite was prepared by an in situ synthesis technique from calcium nitrate, diammoniun hydrogen phosphate, and a cowhide collagen sol at low temperature. XRD and TEM analyses of the composite indicated that crystals formed in the collagen fibril matrix were nanohydroxyapatite with low crystallinity. Biocompatibility of the composite was evaluated by in vitro cytotoxicity test and in vivo genotoxicity and sensitization test. No mutagenic
activity of the composite was observed in mouse micronucleus tests. No evidence of dermal sensitization of the composite was found in guinea pig maximization tests. The results from a filter diffusion test indicated that the composite did not induce a cytotoxic behavior. All these results suggest that the composite has excellent biocompatibility.
Abstract: A porous composite scaffold for tissue engineering had been developed through a novel gel-casting approach with needle-like nano hydroxyapatite (HA) crystallites and chitin. The freeze-dried nano-HA powder was firstly dispersed in the chitin solvent before chitin dissolves in its solvent completely. The composite solution was evenly mixed with a selected porosifier and poured into a mold in which it became a composite gel under the reaction of water molecules in atmosphere. Subsequently, the composite gel was subjected to the simultaneous extraction of the porosifier and
chitin solvent in distilled water. After the drying process the porous composite scaffold was obtained. The morphological analysis showed that the manufactured scaffold had uniform and isotropic porous structure with controlled, fully interconnected pores. In vitro experiments indicated that the bone-like apatite layer formed easily on the walls of the porous n-HA/chitin composite scaffold.