Papers by Author: Quan Li Li

Paper TitlePage

Authors: Zhi Qing Chen, Quan Li Li, Quan Zen, Gang Li, Hao Bin Jiang, Laikui Liu, Brian W. Darvell
Abstract: Phosphorylated chitosans were synthesized as templates to manipulate hydroxyapatite (HA) crystal nucleation, growth and microstructure. Two kinds of insoluble phosphorylated chitosan were soaked in saturated Ca(OH)2 solution for 4 d and in 1.5× SBF (simulated body fluid) solutions for 14 d at 37 °C for biomimetic mineralization. A lower [P]-content of phosphorylated chitosan promoted greater mineralization than higher [P]-content. Phosphorylated chitosan inhibited osteoblast proliferation and differentiation in vitro, while calcium phosphate phosphorylated chitosan composites did not.
Authors: Quan Li Li, Zhi Qing Chen, Guo Min Ou, Laikui Liu, Hao Bin Jiang, Quan Zeng, Gang Li, G. He, An Chun Mo, Brian W. Darvell
Abstract: A novel three-dimensional scaffold of hydroxyapatite(HA)-polyelectrolyte complex (PEC) composite hydrogel was synthesized by a biomimetic method. PEC hydrogel was formed from equal volumes of 1% phosphorylated chitosan in water and 1% chitosan in 1% acetic acid solution. This PEC hydrogel was soaked in saturated Ca(OH)2 solution for 4 d and then in accelerated calcification solution (ACS) for 7 d, both at 37 oC. The PEC hydrogel was a nano-composite material with multiple levels of hierarchical porosity; hydroxyapatite (HA) crystals nucleated and grew on the fiber surfaces of the hydrogel; Rat osteoblasts were then seeded in this three-dimensional scaffold of HA-PEC composite hydrogel, the three-dimensional scaffold of HA-PEC hydrogel revealed excellent biocompatibility.
Authors: Quan Li Li, Zhi Qing Chen, Brian W. Darvell, Quan Zeng, Gang Li, Guo Min Ou, Ming Yue Wu
Abstract: A polyelectrolyte complex (PEC) composed of chitosan (CS) and phosphorylated chitosan (PCS) was used to encapsulate a calcium phosphate by a biomimetic method. An acidic CS (polycation) solution containing calcium and phosphate ions (Ca2+: 6mM, Ca/P = 1.67) was added into PCS (polyanion) solution leading to the formation of a polyelectrolyte complex (PEC) with nanoscopic carbonate-containing, low-crystallinity hydroxyapatite (HA) distributed evenly in the fibrils of the PEC by controlled crystal growth. The resulting composite material, PEC-HA, has a complicated, hierarchical porous structure that is expected to have high bio-compatibity and that may be of use as a carrier for controlled-release therapetic agents.
Authors: Quan Li Li, Nan Huang, Zhi Qing Chen, Xu Yan Tang
Abstract: Phosphorylated chitosan (PCS) was used as the template to control hydroxyapatite(HAp) growth, a novel nanocomposite composed of PCS and HAp was synthesized by biomimetic method. Calcium phosphate (Ca 2+= 60mM, Ca/P = 1.67) solution in HCl was added dropwise into PCS solution in NaOH. The precipitate was lyophilized to obtain the composite. The biocompatibility of the PCS-HAp nanocomopite was evaluated by osteoblast culture in vitro. The results showed that low crystallized HAp nanocrystals was formed on the PCS fibers and its crystallographic c-axis were aligned preferentially parallel to the long axis direction of PCS; the composite have good biocompatibility in vitro. It is expected that the novel composite to be a potential material for bone repair.
Authors: Quan Zeng, Zhi Qing Chen, Quan Li Li, Gang Li, Brian W. Darvell
Abstract: The improvement of the amount of OH functional groups and bioactivity of titanium metal was attempted by chemical treatment and subsequent hot water treatments. The surface morphology, chemical composition and crystal structure were used to characterize the Ti surfaces and their biocompatibility was evaluated by culturing with osteoblasts. Porous network bioactive anatase were prepared by immersion in the 5 M NaOH at 80ı for 24 h, followed by soaking in the water at 80ı for 48 h. The treatment with H2O2/HCl solution at 80ı for 30 min followed by hot water aging also produced an anatase titania gel layer. Percentage of surface OH groups was determined by XPS analysis. After chemical treatment and subsequent aging in hot water, the amount of surface OH groups increased. The modified Ti surface promoted the proliferation and the ALP activities of osteoblasts. These results indicate that the NaOH or H2O2/HCl treatment and subsequent hot water immersion improve the biocompatibility of Ti samples. On the other hand, a high OH group concentration is very important as functional groups for the apatite nucleation or biochemical modification via an organometallic interface of immobilizing biomolecules.
Authors: Quan Li Li, Nan Huang, Guo Jiang Wan, L.S. Zhao, Xu Yan Tang
Abstract: The ultra-thin film composed of chitosan (CS) and sulfated chitosan (SCS) was assembled on the titanium oxide surface by layer-by-layer (LBL) self-assembly methods. The titanium oxide film was treated by NaOH solution, followed by successively dipping the substrates in 5mg/ml sulfated chitosan (SCS) and 5mg/ml chitosan (CS) solutions alternatively, We hypothesized that this biologic coating may have the property of good biocompatibility, antibacteriostatic effect, anticoagulant activitves and enhancing sell biocompatibility.
Showing 1 to 6 of 6 Paper Titles