Papers by Keyword: Polyelectrolyte Complex (PEX)

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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.
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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.
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Authors: Jing Di Chen, Ying Jun Wang, Xiao Feng Chen
Abstract: Owing to the unique characters of the hybrid scaffold components, a novel biodegradable porous composite scaffold was prepared. The nano hydroxyapatite (HAP) (73~136 nm) was crystallized in situ on the organic polyelectrolyte complex matrix through a biomimetic method. The polyelectrolyte complex composed of chitosan and hyaluronic acid had strong impacts on the formation of the nano HAP and directed in situ crystallization of the nano HAP as template. The in situ nano HAP reduced the interfacial energy and presented nano intensifier to the nano hybrid scaffold. Meanwhile, the scaffold kept high porosity.
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Authors: Sung Won Kim, Yun Sik Nam, Yeon Jin Min, Jong Ho Kim, Kwang Meyong Kim, Kui Won Choi, In Sup Noh, Ik Chan Kwon
Abstract: Stability and disintegration of natural polyelectrolyte complex microspheres for protein drugs delivery have been extensively investigated because of their great influence on the drug release patterns. In this study, we tested stability of microspheres with alginate (Alg) core layered by either chitosan (Chi) or glycol chitosan (GChi) by examining release profiles of fluorophorelabeled bovine serum albumin (BSA) and lysozyme (Lys) from the microspheres. While GChi shell was disintegrated quickly, Chi-shell microspheres showed good stability in PBS. Disintegration of the coated layer induced the core material instable. The results indicated that while the charges of the shell material provided additional diffusion barrier against the protein release, the key factor to hold the proteins inside the microspheres was the integrity of the outer coating layer.
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Authors: Po Hui Chen, Ting Yun Kuo, Da Ming Wang, Juin Yih Lai, Hsyue Jen Hsieh
Abstract: Chitosan was used in this study to form polyelectrolyte complex (PEC) with water-soluble acidic polysaccharides, including gum arabic and pectin. Porous membranes made of gum arabic or pectin only were quiet fragile. After incorporating with chitosan, the usability of the membranes was greatly improved. The results showed that the gum arabic/chitosan composite membranes had detectable tensile stress and elongation capability. Moreover, the pectin/chitosan composite membranes had significantly improved tensile stress and elongation capability. Both of the two composite membranes had greater water uptake capability than the membranes composed of chitosan only. We have demonstrated that chitosan can function as a material stabilizer to maintain the solid status of the acidic polysaccharides and thus improve the performance of these acidic polysaccharides.
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