title: 'Smart' nanoparticles as drug delivery systems for applications in tumor therapy.
abstract: BACKGROUND
  In the therapy of clinical diseases such as cancer, it is important to deliver drugs directly to tumor sites in order to maximize local drug concentration and reduce side effects. This objective may be realized by using 'smart' nanoparticles (NPs) as drug delivery systems, because they enable dramatic conformational changes in response to specific physical/chemical stimuli from the diseased cells for targeted and controlled drug release.
  
  
  METHODS
  In this review, we first briefly summarize the characteristics of 'smart' NPs as drug delivery systems in medical therapy, and then discuss their targeting transport, transmembrane and endosomal escape behaviors. Lastly, we focus on the applications of 'smart' NPs as drug delivery systems for tumor therapy.
  
  
  CONCLUSIONS
  Biodegradable 'smart' NPs have the potential to achieve maximum efficacy and drug availability at the desired sites, and reduce the harmful side effects for healthy tissues in tumor therapy. It is necessary to select appropriate NPs and modify their characteristics according to treatment strategies of tumor therapy.
authors.affiliation: a 1 China Three Gorges University, Medical College , Yichang, Hubei 443002, China zhangyanqiong@ctgu.edu.cn ; wujiangfeng@ctgu.edu.cn.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Fang
authors.affiliation: a 1 China Three Gorges University, Medical College , Yichang, Hubei 443002, China zhangyanqiong@ctgu.edu.cn ; wujiangfeng@ctgu.edu.cn.|b 2 China Three Gorges University, Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy , Yichang, Hubei 443002, China.
authors.forename: Lin-Yan
authors.initials: LY
authors.lastname: Wan
authors.affiliation: c 3 Sichuan University, School of Chemical Engineering , Chengdu, Sichuan 610065, China.|d 4 Sichuan University, Collaborative Innovation Center for Biomaterials Science and Technology, State Key Laboratory of Polymer Materials Engineering , Chengdu, Sichuan 610065, China.
authors.forename: Liang-Yin
authors.initials: LY
authors.lastname: Chu
authors.affiliation: a 1 China Three Gorges University, Medical College , Yichang, Hubei 443002, China zhangyanqiong@ctgu.edu.cn ; wujiangfeng@ctgu.edu.cn.
authors.forename: Yan-Qiong
authors.initials: YQ
authors.lastname: Zhang
authors.affiliation: a 1 China Three Gorges University, Medical College , Yichang, Hubei 443002, China zhangyanqiong@ctgu.edu.cn ; wujiangfeng@ctgu.edu.cn.|b 2 China Three Gorges University, Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy , Yichang, Hubei 443002, China.
authors.forename: Jiang-Feng
authors.initials: JF
authors.lastname: Wu
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage*; D003692:Delayed-Action Preparations / Q000008:administration & dosage; D016503:Drug Delivery Systems; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D009369:Neoplasms / Q000188:drug therapy*
chemical_list: D000970:Antineoplastic Agents; D003692:Delayed-Action Preparations
keywords: controlled release; drug delivery; target delivery; tumor therapy; ‘smart’ nanoparticles