title: Effect of the cross-linking agent on performances of NaCS-CS/WSC microcapsules.
abstract: Based on the properties of oppositely charged natural polysaccharides, the polyelectrolyte complexes (PECs) prepared with chitosan-related polycationic polyelectrolytes and cellulose-related polyanionic polyelectrolytes have been widely concerned for their potential applications as micro-drug-carriers for colon. However, the poor mechanical property of the PECs becomes the obstacle encountered in practical applications. This study investigated the effect of the cross-linking agent (sodium polyphosphate, PPS) on the performances of sodium cellulose sulfate -chitosan/water soluble chitosan (NaCS-CS/WSC) microcapsules. The results revealed that PPS could penetrate through the PEC film and form tighter interior structures compared with the microcapsules without the addition of cross-linking agent. The NaCS-CS microcapsules and NaCS-WSC microcapsules with or without PPS had distinct microstructures, which could be ascribed to the different physicochemical properties of CS and WSC. During the formation process, CS can be dissolved in water under acidic conditions, while WSC can be directly dissolved and protonated in acid-free aqueous providing NH3(+) groups quickly, which resulted in the microstructure's difference. Further analysis showed the NaCS-CS-PPS microcapsules and NaCS-WSC-PPS microcapsules had lower swelling ratios due to their tighter interior microstructures that formed. The cross-linking agent had important effect on the total mass of PECs that produced; moreover, the decline of zeta potential of NaCS-CS-PPS microcapsules was lower than that of NaCS-CS microcapsules, similar trend was found in the NaCS-WSC-PPS microcapsules compared with NaCS-WSC microcapsules, indicating the PPS participated in the interactions and played a role in the microcapsules' formation process.
authors: Key Laboratory of Eco-Engineering and Biotechnology of Anhui Province, Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, Hefei 230601, China.
authors: Qing-Xi
authors: QX
authors: Wu
authors: Key Laboratory of Eco-Engineering and Biotechnology of Anhui Province, Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, Hefei 230601, China.
authors: Xin
authors: X
authors: Xu
authors: Key Laboratory of Eco-Engineering and Biotechnology of Anhui Province, Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, Hefei 230601, China.
authors: Zu-Li
authors: ZL
authors: Wang
authors: Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China. Electronic address: yaosj@zju.edu.cn.
authors: Shan-Jing
authors: SJ
authors: Yao
authors: Key Laboratory of Eco-Engineering and Biotechnology of Anhui Province, Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, Hefei 230601, China.
authors: Wang-Yu
authors: WY
authors: Tong
authors: Key Laboratory of Eco-Engineering and Biotechnology of Anhui Province, Integrated Biotechnology Laboratory, School of Life Sciences, Anhui University, Hefei 230601, China.
authors: Yan
authors: Y
authors: Chen
mesh_terms: D002214:Capsules / Q000737:chemistry*; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry*; D011122:Polyphosphates / Q000494:pharmacology*; D017670:Sodium Compounds / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D002214:Capsules; D003432:Cross-Linking Reagents; D004337:Drug Carriers; D011122:Polyphosphates; D017670:Sodium Compounds; D014867:Water; D002482:Cellulose; D048271:Chitosan; C020254:cellulose sulfate
keywords: Chitosan; Cross-linking agent; Microcapsules performances; Polyelectrolyte complexes; Sodium cellulose sulfate