title: Recent Advances of Poly(ether-ether) and Poly(ether-ester) Block Copolymers in Biomedical Applications.
abstract: BACKGROUND
  Poly(ether-ether) and poly(ether-ester) block copolymers have been widely applied in biomedical fields over two decades due to their good safety and biocompatibility. Poly(ethylene glycol), poly(ethylene glycol)-poly(propylene glycol) and poly(lactic-co-glycolic acid) have been approved as excipients by Food and Drug Administration. Because of the broad perspective in biomedical fields, many novel poly(etherether) and poly(ether-ester) block copolymers have been developed for drug delivery, gene therapy and tissue engineering in recent years. This review focuses on active targeting theranostic systems, gene delivery systems and tissue engineering based on poly(ether-ether) and poly(ether-ester) block copolymers.
  
  
  METHODS
  We perform a structured search of bibliographic databases for peer-reviewed scientific reports using a focused review question and inclusion/exclusion criteria. The literatures related to the topics of this review are cataloged according to the developed copolymers or their applications such as active targeting theranostic systems, gene delivery systems and tissue engineering. Some important advances and new trends are summarized in this review.
  
  
  RESULTS
  Some commercial poly(ether-ether) copolymers have been used as excipients for drug research and development. Amphiphilic and biodegradable poly(ether-ester) diblock copolymers are capable of formulating biomedical nanoparticulate theranostic systems, and targeting moiety-functionalized poly(ether-ester) diblock copolymers will be further developed and applied in biomedical nanotechnology fields in the near future. Meanwhile, triblock or multiblock poly(ether-ether) and poly(ether-ester) copolymers with environmentsensitive properties are suitable for gene delivery and tissue engineering. Poly(ether-ether) and poly(ether-ester) copolymers are being extensively applied in active targeting theranostic systems, gene delivery systems and tissue engineering.
  
  
  CONCLUSIONS
  Biodegradable, environment-sensitive and targeting moiety-functionalized block copolymers, which are being applied in active targeting theranostic systems, gene delivery systems and tissue engineering, are promising candidates for treatment of various diseases.
authors.forename: Zhi-Yao
authors.initials: ZY
authors.lastname: He
authors.forename: Kun
authors.initials: K
authors.lastname: Shi
authors.forename: Yu-Quan
authors.initials: YQ
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, 610041, China. anderson-qian@163.com.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Qian
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D004986:Ether / Q000737:chemistry*; D005079:Excipients / Q000737:chemistry; D018014:Gene Transfer Techniques; D006801:Humans; D011091:Polyesters / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D005079:Excipients; D011091:Polyesters; D011108:Polymers; D004986:Ether