Preparation and Characterization of PLGA Nanospheres Surface Modified with Biotinylated Chitosan

【中文摘要】合成了生物素化壳聚糖（Bio-CS)，并通过核磁共振（1H NMR)及电感耦合等离子体光质谱法（ICP-MS）对其进行结构确证。采用溶剂挥发法（W1/O/W2）制备聚乳酸-羟基乙醇酸（PLGA)纳米粒，并通过共价交联法对纳米粒进行Bio-CS表面修饰。未修饰的PLGA纳米粒在扫描电镜下观察呈规则球状形态，平均粒径为（248.4±21.0）nm，Zeta电势为-（21.21±2.13）mV，Bio-CS修饰后的PLGA纳米粒保持球状形态，平均粒径为（268.3±23.4）nm，Zeta电势为（25.45±2.59）mV。采用X射线光电子能谱（XPS)以及试剂盒对纳米粒表面生物素进行定性及定量研究，结果显示，经过Bio-CS修饰后的纳米粒表面含有N,S元素，生物素取代为31%的Bio-CS修饰的PLGA纳米粒，其表面生物素含量为（1.36±0.34）μmol/100mg纳米粒。 【Abstract】Biotinylated chitosan (Bio-CS conjugates or Bio-CS) were synthesized and characterized. The degree of substitution(DS), as defined as the number of biotin per 100 anhydroglucose units of CS, was determined by (1)H NMR and ICP. Poly (lactic-co-glycolic acid) (PLGA) nanospheres were prepared by a solvent evaporation technique(W(1)/O/W(2)). The surface of PLGA nanosphere was modified with Bio-CS by covalent binding. PLGA nanospheres were almost spherical in shape under the scanning electron microscopy (SEM) observation, and their mean diameter determined by the laser light scattering technique was (248.4 +/- 21.0) urn. Bio-CS modified PLGA nanospheres were also spherical in shape; their mean diameter and Zeta potential value were (268.3 +/- 23.4) nm and (21.21 +/- 2.13) mV, respectively. The surface chemistry of nanospheres was quantitatively studied by X-ray photoelectron spectroscopy(XPS). The results show the N region corresponding to the primary amide of CS and the S region corresponding to the biotin, indicating that PLGA nanospheres were successfully surface-modified with Bio-CS. The content of biotin on the surface of Bio-CS modified PLGA nanospheres with DS of biotin of 31% was determined using a commercially available Quant * Tag (TM) Biotin Kit and its value was (1.36 +/- 0.34) mol/100 mg