title: Synthesis, characterization, and biocompatibility of alternating block  polyurethanes based on PLA and PEG.
abstract: A series of alternating block polyurethanes (abbreviated as PULA-alt-PEG) and random block polyurethanes (abbreviated as PULA-ran-PEG) based on poly(L-lactic acid) (PLA) and poly(ethylene glycol) (PEG) were synthesized. The differences of PULA-alt/ran-PEG chemical structure, molecular weight, distribution, thermal properties, mechanical properties and static contact angle were systematically investigated. The PULA-alt/ran-PEG polyurethanes exhibited low T(g) (-47.3 ∼ -34.4°C), wide mechanical properties (stress σ(t): 4.6-32.6 MPa, modulus E: 11.4-323.9 MPa and strain ε: 468-1530%) and low water contact angle (35.4-51.4°). Scanning electron microscope (SEM) observation showed that PULA-alt-PEG film displays rougher and more patterned surface morphology than PULA-ran-PEG does, due to more regular structures of PULA-alt-PEG. Hydrolytic degradation shows that degradation rate of random block polyurethane series PULA-ran-PEG is higher than the alternating counterpart PULA-alt-PEG. PLA segment degradation is faster than urethane linkage and PEG segment almost does not degrade in the buffer solution. Platelet adhesion study showed that all the polyurethanes possess excellent hemocompatibility. The cell culture assay revealed that PULA-alt/ran-PEG polyurethanes were cell inert and unfavorable for the attachment of rat glial cell due to the hydrophilic characters of the materials.
authors.forename: Tingzhen
authors.initials: T
authors.lastname: Mei
authors.forename: Yonghe
authors.initials: Y
authors.lastname: Zhu
authors.forename: Tongcui
authors.initials: T
authors.lastname: Ma
authors.forename: Tao
authors.initials: T
authors.lastname: He
authors.forename: Linjing
authors.initials: L
authors.lastname: Li
authors.forename: Chiju
authors.initials: C
authors.lastname: Wei
authors.forename: Kaitian
authors.initials: K
authors.lastname: Xu
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D002478:Cells, Cultured; D006801:Humans; D006868:Hydrolysis; D019344:Lactic Acid / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D008422:Materials Testing; D009457:Neuroglia / Q000166:cytology; D010973:Platelet Adhesiveness; D011091:Polyesters; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D011140:Polyurethanes / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D011091:Polyesters; D011108:Polymers; D011140:Polyurethanes; D019344:Lactic Acid; D011092:Polyethylene Glycols; C033616:poly(lactide)