胆固醇改性海藻酸.pdfVIP

Carbohydrate Polymers 68 (2007) 218–225 /locate/carbpol Amphiphilic cholesteryl grafted sodium alginate derivative: Synthesis and self-assembly in aqueous solution Liqun Yang *, Bifang Zhang, Liqun Wen, Qiuyi Liang, Li-Ming Zhang Institute of Polymer Science, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China Received 29 September 2006; received in revised form 17 December 2006; accepted 17 December 2006 Available online 27 December 2006 Abstract A novel water soluble amphiphilic sodium alginate derivative grafted with 3 cholesteryl groups per 100 hexuronic acid residues (CSAD-3) has been first synthesized with N,N0 0 -dicyclohexylcarbodiimide as a coupling agent and 4-(N,N -dimethylamino)pyridine as a catalyst at room temperature. The result of fluorescence analysis shows that CSAD-3 forms self-aggregates in 0.15 mol/L aqueous NaCl solution and its critical aggregation concentration (CAC) is 0.33 g/L. The value of CAC decreases with increase of the concentra- tion of aqueous NaCl solution. The CSAD-3 self-aggregates are able to encapsulate hydrophobic compounds like pyrene. The hydro- dynamic diameter of CSAD-3 self-aggregates in aqueous NaCl solution is 136 nm determined by dynamic light scattering measurement. The oblate particles with the size about 100–200 nm are observed in the negatively dyed TEM image of CSAD-3 self- aggregates. 2007 Elsevier Ltd. All rights reserved. Keywords: Sodium algi