title: Folate-decorated and reduction-sensitive micelles assembled from amphiphilic polymer-camptothecin conjugates for intracellular drug delivery.
abstract: It is one of the challenges for a wide clinical application of polymer micelles to address the structure disintegration and premature drug release before reaching a pathological site. In the current study, folic acid (FA)-decorated polymer-drug conjugates (FSC) were synthesized with disulfide linkages between camptothecin (CPT) and amphiphilic poly(ethylene glycol)-b-poly(ε-caprolactone) (PECL) copolymers. FSC conjugates were proposed to assemble into micelles with a hydrophobic core of PCL segments and CPT and a hydrophilic corona of PEG segments. The addition of hexadecanol during micelle formation (FSC-16) was proposed to modulate the interactions of hydrophobic segments in micelles and enhance the reductive sensitivity. FSC-16 micelles were obtained with critical micelle concentration of around 2 μg/mL and an average size of around 200 nm, and the conjugated CPT was rapidly released out in response to glutathione. The reductive sensitivity was also demonstrated with respect to the changes of micelle size and morphologies as well as the fluorescent intensity of pyrene loaded in micelles. Benefiting from the FA receptor-mediated uptake and the reduction-sensitive release of CPT, significant cytotoxicity and cell apoptosis were identified for FSC-16 micelles against SKOV-3 cells with strong expressions of FA receptors. Flow cytometry and confocal laser scanning microscopy analyses demonstrated that CPT was distributed into nuclei after cellular uptake and intracellular release from FSC-16 micelles. Thus, the FA-decorated and reduction-sensitive micelles assembled from polymer-drug conjugates show advantages in inhibiting premature release during circulation, enhancing cellular uptake at the tumor tissues, and promoting intracellular release and nuclei location of the active moieties.
authors.affiliation: Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, School of Materials Science and Engineering, Southwest Jiaotong University , Chengdu 610031, P. R. China.
authors.forename: Chaoyu
authors.initials: C
authors.lastname: Liu
authors.forename: Jiang
authors.initials: J
authors.lastname: Yuan
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Luo
authors.forename: Maohua
authors.initials: M
authors.lastname: Chen
authors.forename: Zhoujiang
authors.initials: Z
authors.lastname: Chen
authors.forename: Yuancong
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Li
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000493:pharmacokinetics / Q000494:pharmacology; D002166:Camptothecin / Q000493:pharmacokinetics / Q000494:pharmacology*; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers; D016503:Drug Delivery Systems; D005260:Female; D005492:Folic Acid / Q000737:chemistry*; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007783:Lactones / Q000737:chemistry*; D008823:Micelles; D015394:Molecular Structure; D010051:Ovarian Neoplasms / Q000188:drug therapy* / Q000473:pathology; D011092:Polyethylene Glycols / Q000737:chemistry*; D013499:Surface Properties; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D004337:Drug Carriers; D007783:Lactones; D008823:Micelles; C521904:poly(ethylene glycol)-block-poly(epsilon-caprolactone); D011092:Polyethylene Glycols; D005492:Folic Acid; D002166:Camptothecin
keywords: disulfide linkage; folic acid decoration; nucleus localization; polymer−drug conjugate micelle; reductive sensitivity