title: Novel dual-control poly(N-isopropylacrylamide-co-chlorophyllin) nanogels for improving drug release.
abstract: OBJECTIVE
  How to overcome insufficient drug release is an important issue in the drug-delivery system.
  
  
  METHODS
  Here, a novel temperature and UV dual-control poly(N-isopropylacrylamide [PNIPAM]-co-chlorophyllin) nanogel was prepared via the surfactant-free emulsion polymerization.
  
  
  RESULTS
  The introduction of hydrophilic chlorophyllin to the PNIPAM chain backbone led to a narrow size of poly[NIPAM-co-CHLN nanogel (D ∼180 nm) confirmed by atomic force microscopy and transmission electron microscopy. This nanogel had a lower critical solution temperature (∼35°C), observed by dynamic laser light scattering. After the phase transition, the size under UV light (50 nm) was much smaller than that induced by temperature (90 nm). The inhomogeneous collapse was attributed to the temperature-gradient generated from the gel surface to the core with a surrounding dense PNIPAM layer. The obstacles that strongly inhibited 5-fluorouracil release was successfully overcome by light irradiation via a large drug diffusion coefficient.
  
  
  CONCLUSIONS
  Consequently, the novel dual functional nanogel is potent for improving the drug-release profile.
authors.affiliation: International Joint Cancer Institute, The Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Qingchenig
authors.initials: Q
authors.lastname: Guo
authors.forename: He
authors.initials: H
authors.lastname: Zhao
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Weizhu
authors.initials: W
authors.lastname: Qian
authors.forename: Bohua
authors.initials: B
authors.lastname: Li
authors.forename: Huaiwen
authors.initials: H
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Jianxin
authors.initials: J
authors.lastname: Dai
authors.forename: Yajun
authors.initials: Y
authors.lastname: Guo
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage*; D002735:Chlorophyllides / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D005472:Fluorouracil / Q000008:administration & dosage*; D005782:Gels / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D044367:Phase Transition; D013696:Temperature; D014466:Ultraviolet Rays
chemical_list: D000180:Acrylic Resins; D000964:Antimetabolites, Antineoplastic; D002735:Chlorophyllides; D003692:Delayed-Action Preparations; D005782:Gels; C052970:poly-N-isopropylacrylamide; C007020:chlorophyllin; D005472:Fluorouracil