PMID- 23167676
OWN - NLM
STAT- MEDLINE
DCOM- 20130521
LR  - 20181202
IS  - 1526-4602 (Electronic)
IS  - 1525-7797 (Linking)
VI  - 13
IP  - 12
DP  - 2012 Dec 10
TI  - Biodegradable hyperbranched amphiphilic polyurethane multiblock copolymers 
      consisting of poly(propylene glycol), poly(ethylene glycol), and polycaprolactone 
      as in situ thermogels.
PG  - 3977-89
LID - 10.1021/bm3012506 [doi]
AB  - This paper reports the synthesis and characterization of new hyperbranched 
      amphiphilic polyurethane multiblock copolymers consisting of poly(propylene 
      glycol) (PPG), poly(ethylene glycol) (PEG), and polycaprolactone (PCL) segments 
      as in situ thermogels. The hyperbranched poly(PPG/PEG/PCL urethane)s, termed as 
      HBPEC copolymers, were synthesized from PPG-diol, PEG-diol, and PCL-triol by 
      using 1,6-hexamethylene diisocyanate (HMDI) as a coupling agent. The compositions 
      and structures of HBPEC copolymers were determined by GPC and 1H NMR 
      spectroscopy. We carried out comparative studies of the new hyperbranched 
      copolymers with their linear counterparts, the linear poly(PPG/PEG/PCL urethane) 
      (LPEC) copolymer and Pluronic F127 PEG-PPG-PEG block copolymer, in terms of their 
      self-assembly and aggregation behaviors and thermoresponsive properties. HBPEC 
      copolymers were found to show thermoresponsive micelle formation and aggregation 
      behaviors. Particularly, the lower critical solution temperature (LCST) of the 
      copolymers was significantly affected by the copolymer architecture. HBPEC 
      copolymers showed much lower LCST than LPEC, the linear counterpart. Our studies 
      revealed that the effect of hyperbranch architecture was more prominent in the 
      gelation of the copolymers. The aqueous solutions of HBPEC copolymers exhibited 
      thermogelling behaviors at critical gelation concentrations (CGCs) ranging from 
      4.3 to 7.4 wt %. These values are much lower than those reported on other 
      PCL-contained linear thermogelling copolymers and Pluronic F127 copolymer. In 
      addition, the CGC of HBPEC copolymers is much lower than the control LPEC 
      copolymer. More interestingly, at high temperatures, while LPEC and other linear 
      thermogelling copolymers formed turbid sol, HBPEC formed a dehydrated gel. Our 
      data suggest that these phenomena are caused by the hyperbranched structure of 
      HBPEC copolymers, which could increase the interaction of copolymer branches and 
      enhance the chain association through synergetic hydrogen bonding effect. The 
      thermogelling behavior of HBPEC block copolymers was further evidenced by the 1H 
      NMR molecular dynamic study and rheological study, which further support the 
      above hypothesis. The hydrolytic degradation study showed that the HBPEC 
      copolymer hydrogels are biodegradable under physiological conditions. Together 
      with the good cell biocompatibility demonstrated by the cytotoxicity study, the 
      new thermogelling copolymers reported in this paper could potentially be used as 
      in situ-forming hydrogels for biomedical applications.
FAU - Li, Zibiao
AU  - Li Z
AD  - Department of Bioengineering, Faculty of Engineering, National University of 
      Singapore, 7 Engineering Drive 1, Singapore 117574, Singapore.
FAU - Zhang, Zhongxing
AU  - Zhang Z
FAU - Liu, Kerh Li
AU  - Liu KL
FAU - Ni, Xiping
AU  - Ni X
FAU - Li, Jun
AU  - Li J
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20121120
PL  - United States
TA  - Biomacromolecules
JT  - Biomacromolecules
JID - 100892849
RN  - 0 (Biocompatible Materials)
RN  - 0 (Cyanates)
RN  - 0 (Hydrogels)
RN  - 0 (Isocyanates)
RN  - 0 (Micelles)
RN  - 0 (Polyesters)
RN  - 0 (Polyurethanes)
RN  - 0 (Propylene Glycols)
RN  - 0 (poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) 
      copolymer)
RN  - 0I70A3I1UF (1,6-hexamethylene diisocyanate)
RN  - 24980-41-4 (polycaprolactone)
RN  - 3WJQ0SDW1A (Polyethylene Glycols)
SB  - IM
MH  - Animals
MH  - Biocompatible Materials/*chemical synthesis
MH  - Cell Line
MH  - Cell Survival
MH  - Cyanates/metabolism
MH  - Hydrogels/chemistry
MH  - Isocyanates
MH  - Magnetic Resonance Spectroscopy/methods
MH  - Mice
MH  - Micelles
MH  - Microscopy, Electron, Transmission
MH  - Particle Size
MH  - Polyesters/*chemistry
MH  - Polyethylene Glycols/*chemical synthesis
MH  - Polyurethanes/*chemistry
MH  - Propylene Glycols/*chemical synthesis
MH  - Thermodynamics
EDAT- 2012/11/22 06:00
MHDA- 2013/05/23 06:00
CRDT- 2012/11/22 06:00
PHST- 2012/11/22 06:00 [entrez]
PHST- 2012/11/22 06:00 [pubmed]
PHST- 2013/05/23 06:00 [medline]
AID - 10.1021/bm3012506 [doi]
PST - ppublish
SO  - Biomacromolecules. 2012 Dec 10;13(12):3977-89. doi: 10.1021/bm3012506. Epub 2012 
      Nov 20.