聚水杨酸氧化还原响应型纳米载药系统的制备及体外评价

Preparation and in Vitro Evaluation of Redox-responsive Nano-drug Delivery System of Poly-salicylic Acid

关键词:  聚水杨酸  O-羧甲基壳聚糖  肝癌  氧化还原响应

Key words:  poly-salicylic acid  O-carboxymethyl chitosan  liver cancer  redox-responsive

摘要:

目的 将聚水杨酸(poly-salicylic acid，PSA)连接到羧甲基壳聚糖上，使其形成自组装纳米粒(nanoparticles，NPs)，并进行表征和体外评价。方法 以O-羧甲基壳聚糖(O-carboxymethyl chitosan，OCMC)作为亲水骨链，通过二硫键将PSA连接在羧甲基壳聚糖上。利用核磁共振氢谱(¹H-NMR)、红外光谱(IR)确证聚合物的结构；采用超声法制备自组装NPs，并对其粒径、Zeta电位进行表征；采用芘荧光探针法测定NPs的临界聚集浓度(critical aggregation concentration，CAC)；测定载DOX NPs包封率和载药量；MTT试验考察载药NPs的体外抗肿瘤活性。结果 OCMC二硫键连接PSA NPs(OCMC-SS-PSA NPs)的粒径为(148.5±2.3)nm；CAC值为(0.069 3±0.001 3)mg·mL^-1；还原响应性和pH敏感性良好。DOX/OCMC-SS-PSA NPs的粒径为(160.5±1.7)nm，载药量为(17.43±0.56)%，包封率为(89.67±1.23)%。MTT试验表明OCMC-SS-PSA NPs具有良好的生物安全性；细胞摄取试验表明DOX/OCMC-SS-PSA NPs在细胞内滞留时间更长。结论 OCMC-SS-PSA NPs粒径较小，具有良好的还原响应性、pH敏感性和生物安全性。OCMC-SS-PSA NPs可作为兼具还原响应性和pH敏感性的纳米给药系统。

Abstract:

OBJECTIVE To connect poly-salicylic acid(PSA) to carboxymethyl chitosan to form self-assembled nanoparticles(NPs), and conduct characterization and in vitro evaluation. METHODS O-carboxymethyl chitosan(OCMC) was used as a hydrophilic bone chain to connect PSA to carboxymethyl chitosan through disulfide bond. The structure of the copolymer was confirmed by ¹H-NMR and IR. Self assembled NPs were prepared by ultrasonic method, and their particle size and Zeta potential were characterized. The critical aggregation concentration(CAC) of NPs was determined by pyrene fluorescence probe method. The encapsulation efficiency and drug loading of DOX loaded NPs were determined. MTT assay was used to investigate the anti-tumor activity of drug loaded NPs in vitro. RESULTS The particle size of OCMC disulfide bonded poly-salicylic acid NPs(OCMC-SS-PSA NPs) was (148.5±2.3)nm; CAC value was (0.069 3±0.001 3)mg·mL^-1; its reduction sensitivity and pH sensitivity was good. The particle size of DOX/OCMC-SS-PSA NPs was (160.5±1.7)nm, the drug loading was (17.43±0.56)%, and the encapsulation efficiency was (89.67±1.23)%. MTT test showed that OCMC-SS-PSA NPs had good biological safety; the cell uptake experiment showed that DOX/OCMC-SS-PSA NPs stayed longer in the cells. CONCLUSION OCMC-SS-PSA NPs have small particle size, good reduction responsiveness, pH sensitivity and biosafety. OCMC-SS-PSA NPs can be used as a new nano drug delivery system with both reduction response and pH sensitivity.