Paclitaxel-loaded PLA/PEG/fluorescein anticancer agent prepared by Ugi reaction

Two different fluorescent block copolymers of poly(lactic acid) (PLA) and polyethylene glycol (PEG) containing fluorescein grafted to the polymer chain were synthesized by Ugi four-component condensation (UFCC). The structure of these PEG–PLA copolymers was confirmed by ¹H-NMR and fluorescence spectroscopy. Paclitaxel-loaded fluorescent microspheres (PCT-FMS1 and PCT-FMS2) were prepared from them by the single-emulsion solvent evaporation method. A kinetic study of drug release in vitro using high-performance liquid chromatography showed a prolonged and controlled release of paclitaxel. Anticancer activity of release medium against colorectal cancer cell line (Caco-2) was determined using the cell viability assay. Paclitaxel-loaded microspheres were able to inhibit cancer cell growth and colony formation. The main contribution of this work is to propose a new application for UFCC in the preparation of biomasked fluorescent drug delivery systems able to improve cancer treatment.     

Influence of racemization on stereocomplex‐induced gelation of water‐soluble polylactide–poly(ethylene glycol) block copolymers

Ring‐opening polymerization of L ‐ or D ‐lactide was realized at 140 °C for a period of 7 days in the presence of dihydroxyl poly(ethylene glycol) (PEG), with M?_n = 4000 g mol^?1, using zinc lactate as initiator. The resulting poly(L ‐lactide)–PEG–poly(L ‐lactide) and poly(D ‐lactide)–PEG–poly(D ‐lactide) triblock copolymers are water soluble with polylactide (PLA) block length ranging from 11 to 17 units. Both the tube inverting method and rheological measurements were used to evaluate the gelation properties of aqueous solutions containing single copolymers or L /D copolymer pairs. Stereocomplexation between poly(L ‐lactide) and poly(D ‐lactide) blocks is observed for mixed solutions. Hydrogel formation is detected in the case of relatively long PLA blocks (DP _PLA = 17), but not for copolymers with shorter PLA blocks (DP _PLA = 11–13) due to partial racemization of L ‐lactyl units. Racemization is largely reduced when the reaction time is shortened to 1 day. Under these conditions, DP _PLA of 8 is sufficient for the stereocomplexation of PLA–PEG block copolymers, and DP _PLA above 10 leads to the formation of hydrogels of PLA–PEG block copolymers. On the other hand, racemization appears as a general phenomenon in the (co)polymerization of L ‐lactide with Zn(Lac)₂ as initiator, although it is negligible or undetectable in the case of high molar mass polymers. Therefore, racemization is the limiting factor for the stereocomplexation‐induced gelation of water‐soluble PLA–PEG block copolymers where the PLA block length generally ranges from 10 to 30. Reaction conditions including initiator, time and temperature should be strictly controlled to minimize racemization. Copyright © 2010 Society of Chemical Industry     

Preparation and degradability of poly(lactic acid)–poly(ethylene glycol)–poly(lactic acid)/SiO2 hybrid material

Poly(lactic acid)–poly(ethylene glycol)–poly(lactic acid) (PLA‐PEG‐PLA)/SiO₂ hybrid material is prepared by sol–gel method using tetraethoxysilane (TEOS) and PLA‐PEG‐PLA as raw material. From Fourier transform infrared spectroscopy (FTIR) and X‐ray photoelectron spectroscopy (XPS) spectra, the hydroxyl groups of the silica sol derived from partially hydrolysis of TEOS and the unhydrolyzed ethoxy groups of TEOS can react with PLA‐PEG‐PLA. Differential scanning calorimetry (DSC) curves imply that the glass transition temperature (T_g) of PLA‐PEG‐PLA/SiO₂ hybrid material is higher than that of PLA‐PEG‐PLA and increases with the increase of silica content. X‐ray diffraction (XRD) analysis results show that PLA‐PEG‐PLA and PLA‐PEG‐PLA/SiO₂ hybrid material are both amorphous. Field scanning electron microscope (FSEM) photographs show that when PLA‐PEG‐PLA/SiO₂ hybrid material has been degraded for 12 weeks in normal saline at 37°C, a three‐dimensional porous scaffold is obtained, which is available for cell growth and metabolism. Moreover, the hydroxyl (? OH) groups on SiO₂ of PLA‐PEG‐PLA/SiO₂ hybrid material could buffer the acidity resulted from the degradation of PLA, which is beneficial to proliferation of cell in tissue repairing. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of double‐hydrophilic poly(methylacrylic acid)–poly(ethylene glycol)–poly(methylacrylic acid) triblock copolymers and their micelle formation

The aim of the work reported was to synthesize a series of double‐hydrophilic poly(methacrylic acid)‐block‐poly(ethylene glycol)‐block‐poly(methacrylic acid) (PMAA‐b‐PEG‐b‐PMAA) triblock copolymers and to study their self‐assembly behavior. These copolymeric self‐assembly systems are expected to be potential candidates for applications as carriers of hydrophilic drugs. Bromo‐terminated difunctional PEG macroinitiators were used to synthesize well‐defined triblock copolymers of poly(tert‐butyl methacrylate)‐block‐poly(ethylene glycol)‐block‐poly(tert‐butyl methacrylate) via reversible‐deactivation radical polymerization. After the removal of the tert‐butyl group by hydrolysis, double‐hydrophilic PMAA‐b‐PEG‐b‐PMAA triblock copolymers were obtained. pH‐sensitive spherical micelles with a core–corona structure were fabricated by self‐assembly of the double‐hydrophilic PMAA‐b‐PEG‐b‐PMAA triblock copolymers at lower solution pH. Transmission electron microscopy and laser light scattering studies showed the micelles were of nanometric scale with narrow size distribution. Solution pH and micelle concentration strongly influenced the hydrodynamic radius of the spherical micelles (48–310 nm). A possible reason for the formation of the micelles is proposed. Copyright © 2010 Society of Chemical Industry     

Self‐assembled micelles prepared from poly(ɛ‐caprolactone)–poly(ethylene glycol) and poly(ɛ‐caprolactone/glycolide)–poly(ethylene glycol) block copolymers for sustained drug delivery

A series of poly(?‐caprolactone)–poly(ethylene glycol) (PCL‐PEG) and poly(?‐caprolactone/glycolide)–poly(ethylene glycol) [P(CL/GA)‐PEG] diblock copolymers were prepared by ring‐opening polymerization of ?‐caprolactone or a mixture of ?‐caprolactone and glycolide using monomethoxy PEG (mPEG) as macroinitiator and Sn(Oct)₂ as catalyst. The resulting copolymers were characterized using ¹H‐NMR, gel permeation chromatography, differential scanning calorimetry, and wide‐angle X‐ray diffraction. Copolymer micelles were prepared using the nanoprecipitation method. The morphology of the micelles was spherical or worm‐like as revealed by transmission electron microscopy, depending on the copolymer composition and the length of the hydrophobic block. Introduction of the glycolide component, even in small amounts (CL/GA = 10), disrupted the chain structure and led to the formation of spherical micelles. Interestingly, the micelle size decreased with the encapsulation of paclitaxel. Micelles prepared from mPEG5000‐derived copolymers exhibited better drug loading properties and slower drug release than those from mPEG2000‐derived copolymers. Drug release was faster for copolymers with shorter PCL blocks than for those with longer PCL chains. The introduction of glycolide moieties enhanced drug release, but the overall release rate did not exceed 10% in 30 days. In contrast, drug release was enhanced in acidic media. Therefore, these bioresorbable micelles and especially P(CL/GA)‐PEG micelles with excellent stability, high drug loading content, and prolonged drug release could be promising for applications as drug carriers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45732.     

ABA triblock copolymers from poly(p‐dioxanone) and poly(ethylene glycol)

Poly(p‐dioxanone)–poly(ethylene glycol)–poly(p‐dioxanone) ABA triblock copolymers (PEDO) were synthesized by ring‐opening polymerization from p‐dioxanone using poly(ethylene glycol) (PEG) with different molecular weights as macroinitiators in N₂ atmosphere. The copolymer was characterized by ¹H NMR spectroscope. The thermal behavior, crystallization, and thermal stability of these copolymers were investigated by differential scanning calorimetry and thermogravimetric measurements. The water absorption of these copolymers was also measured. The results indicated that the content and length of PEG chain have a greater effect on the properties of copolymers. This kind of biodegradable copolymer will find a potential application in biomedical materials. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:1092–1097, 2006     

Synthesis and characterization of poly(ϵ‐caprolactone)–poly(L‐lactide) diblock copolymers with an organic amino calcium catalyst

The quasiliving characteristics of the ring‐opening polymerization of ?‐caprolactone (CL) catalyzed by an organic amino calcium were demonstrated. Taking advantage of this feature, we synthesized a series of poly(?‐caprolactone) (PCL)–poly(L ‐lactide) (PLA) diblock copolymers with the sequential addition of the monomers CL and L ‐lactide. The block structure was confirmed by ¹H‐NMR, ¹³C‐NMR, and gel permeation chromatography analysis. The crystalline structure of the copolymers was investigated by differential scanning calorimetry and wide‐angle X‐ray diffraction analysis. When the molecular weight of the PLA block was high enough, phase separation took place in the block copolymer to form PCL and PLA domains, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2654–2660, 2006     

Synthesis of polylactide/poly(ethylene glycol) diblock copolymers with functional endgroups

Amphiphilic polylactide/poly(ethylene glycol) (PLA–PEG) diblock copolymers with functional groups at the PEG chain ends were synthesized by coupling PLA and PEG homopolymers using different coupling agents. PLA precursors with different endgroups were synthesized by ring‐opening polymerization of l ‐lactide in the presence of different initiators such as octanol, acetic acid or benzoic acid, or water, using non‐toxic zinc lactate as catalyst. The mechanism of the ring‐opening polymerization of lactide initiated by carboxyl groups was investigated and discussed in comparison with the literature. N,N'‐carbonyldiimidazole was used to couple the two hydroxyl groups of PLA and PEG, using 4‐dimethylaminopyridine (DMAP) as catalyst. Dicyclohexylcarbodiimide (DCC) and DMAP were adopted to couple the carboxyl group and the hydroxyl group of PLA and PEG, respectively, while DCC and N‐hydroxysuccinimide were used to connect PLA and PEG by coupling their carboxyl and amine groups. Comparison of different coupling routes shows that the DCC/DMAP one exhibits the highest efficiency. A common tumor targeting ligand, folic acid, was attached to PLA–PEG with hydroxyl endgroups using the DCC/DMAP route. The resulting PLA–PEG copolymers bearing folic acid present great interest for targeted delivery of anti‐cancer drugs. © 2012 Society of Chemical Industry     

pH and thermo‐responsive poly(N‐isopropylacrylamide) copolymer grafted to poly(ethylene glycol)

pH and thermo‐responsive graft copolymers are reported where thermo‐responsive poly(N‐isopropylacrylamide) [poly(NIPAAm), poly A ], poly(N‐isopropylacrylamide‐co‐2‐(diethylamino) ethyl methacrylate) [poly(NIPAAm‐co‐DEA), poly B ], and poly(N‐isopropylacrylamide‐co‐methacrylic acid) [poly(NIPAAm‐co‐MAA), poly C ] have been installed to benzaldehyde grafted polyethylene glycol (PEG) back bone following introducing a pH responsive benzoic‐imine bond. All the prepared graft copolymers for PEG‐g‐poly(NIPAAm) [ P‐N1 ], PEG‐g‐poly(NIPAAm‐co‐DEA) [ P‐N2 ], and PEG‐g‐poly(NIPAAm‐co‐MAA) [ P‐N3 ] were characterized by ¹H‐NMR to assure the successful synthesis of the expected polymers. Molecular weight of all synthesized polymers was evaluated following gel permeation chromatography. The lower critical solution temperature of graft copolymers varied significantly when grafted to benzaldehyde containing PEG and after further functionalization of copolymer based poly(NIPAAm). The contact angle experiment showed the changes in hydrophilic/hydrophobic behavior when the polymers were exposed to different pH and temperature. Particle size measurement investigation by dynamic light scattering was performed to rectify thermo and pH responsiveness of all prepared polymers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Synthesis and characterization of poly(dimethylamino ethyl methacrylate)–poly(ethylene oxide)–poly(dimethylamino ethyl methacrylate) triblock copolymers

Novel, monodispersed, and well‐defined ABA triblock copolymers [poly(dimethylamino ethyl methacrylate)–poly(ethylene oxide)–poly(dimethylamino ethyl methacrylate)] were synthesized by oxyanionic polymerization with potassium tert‐butanoxide as the initiator. Gel permeation chromatography and ¹H‐NMR analysis showed that the obtained products were the desired copolymers with molecular weights close to calculated values. Because the poly(dimethylamino ethyl methacrylate) block was pH‐ and temperature‐sensitive, the aqueous solution behavior of the polymers was investigated with ¹H‐NMR and dynamic light scattering techniques at different pH values and at different temperatures. The micelle morphology was determined with transmission electron microscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of the synthesis conditions on the structural and thermal properties of poly(l‐lactide)‐b‐poly(ethylene glycol)‐b‐poly(l‐lactide)

The poly(l ‐lactide)‐b‐poly(ethylene glycol)‐b‐poly(l ‐lactide) block copolymers (PLLA‐b‐PEG‐b‐PLLA) were synthesized in a toluene solution by the ring‐opening polymerization of 3,6‐dimethyl‐1,4‐dioxan‐2,5‐dione (LLA) with PEG as a macroinitiator or by transterification from the homopolymers [polylactide and PEG]. Two polymerization conditions were adopted: method A, which used an equimolar catalyst/initiator molar ratio (1–5 wt %), and method B, which used a catalyst content commonly reported in the literature (<0.05 wt %). Method A was more efficient in producing copolymers with a higher yield and monomer conversion, whereas method B resulted in a mixture of the copolymer and homopolymers. The copolymers achieved high molar masses and even presenting similar global compositions, the molar mass distribution and thermal properties depends on the polymerization method. For instance, the suppression of the PEG block crystallization was more noticeable for copolymer A. An experimental design was used to qualify the influence of the catalyst and homopolymer amounts on the transreactions. The catalyst concentration was shown to be the most important factor. Therefore, the effectiveness of method A to produce copolymers was partly due to the transreactions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40419.     

Synthesis and characterization of a poly(ether–ester) copolymer from poly(2,6 dimethyl‐1,4‐phenylene oxide) and poly(ethylene terephthalate)

A series of poly(ether–ester) copolymers were synthesized from poly(2,6 dimethyl‐1,4‐phenylene oxide) (PPO) and poly(ethylene terephthalate) (PET). The synthesis was carried out by two‐step solution polymerization process. PET oligomers were synthesized via glycolysis and subsequently used in the copolymerization reaction. FTIR spectroscopy analysis shows the coexistence of spectral contributions of PPO and PET on the spectra of their ether–ester copolymers. The composition of the poly(ether–ester)s was calculated via ¹H NMR spectroscopy. A single glass transition temperature was detected for all synthesized poly(ether–ester)s. T_g behavior as a function of poly(ether–ester) composition is well represented by the Gordon‐Taylor equation. The molar masses of the copolymers synthesized were calculated by viscosimetry. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Antielectrostatic poly(ether ester) block copolymer of poly(ethylene terephthalate‐co‐isophthalate)–poly(ethylene glycol)

Poly(ethylene terephthalate) (PET) fiber has a low moisture regain, which allows it to easily gather static charges, and many investigations have been carried out on this problem. In this study, a series of poly(ethylene terephthalate‐co‐isophthalate) (PEIT)–poly(ethylene glycol) (PEG) block copolymers were prepared by the incorporation of isophthalic acid (IPA) during esterification and PEG during condensation. PEG afforded PET with an increased moisture affinity, which in turn, promoted the leakage of static charges. However, PET also then became easier to crystallize, even at room temperature, which led to decreased antistatic properties and increased manufacturing inconveniences. IPA was, therefore, used to reduce the crystallinity of the copolymers and, at the same time, make their crystal structure looser for increased water absorption. Moreover, PET fibers with incorporated IPA and PEG showed good dyeability. In this article, the structural characterization of the copolymers and antistatic and mechanical properties of the resulting fibers are discussed. At 4 wt % IPA, the fiber containing 1 mol % PEG with a molecular weight of 1000 considerably improved antistatic properties and other properties. In addition, the use of PEIT–PEG as an antistatic agent blended with PET or modified PET fibers also benefitted the antistatic properties. Moreover, PEIT–PEG could be used with another antistatic agent to produce fibers with a low volume resistance. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1696–1701, 2003     

Synthesis and characterization of poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers

Poly(L‐lactide)‐poly(ethylene glycol) multiblock copolymers with predetermined block lengths were synthesized by polycondensation of PLA diols and PEG diacids. The reaction was carried out under mild conditions, using dicyclohexylcarbodiimide as the coupling agent and dimethylaminopyridine as the catalyst. The resulting copolymers were characterized by various analytical techniques, such as GPC, viscometry, ¹H‐NMR, FTIR, DSC, X‐ray diffractometry, and contact angle measurement. The results indicated that these copolymers presented outstanding properties pertinent to biomedical use, including better miscibility between the two components, low crystallinity, and hydrophilicity. Moreover, the properties of the copolymers can be modulated by adjusting the block length of the two components or the reaction conditions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1729–1736, 2002; DOI 10.1002/app.10580     

Synthesis and hydrophilicity of poly(butylene 2,6‐naphthalate)/poly(ethylene glycol) copolymers

Poly(butylene 2,6‐naphthalate) (PBN)/poly(ethylene glycol) (PEG) copolymers were synthesized by the two‐step melt copolymerization process of dimethyl‐2,6‐naphthalenedicarboxylate (2,6‐NDC) with 1,4‐butanediol (BD) and PEG. The copolymers produced had different PEG molecular weights and contents. The structures, thermal properties, and hydrophilicities of these copolymers were studied by ¹H NMR, DSC, TGA, and by contact angle and moisture content measurements. In particular, the intrinsic viscosities of PBN/PEG copolymers increased with increasing PEG molecular weights, but the melting temperatures (T_m)_, the cold crystallization temperatures (T_cc)_, and the heat of fusion (ΔH_f) values of PBN/PEG copolymers decreased on increasing PEG contents or molecular weights. The thermal stabilities of the copolymers were unaffected by PEG content or molecular weight. Hydrophilicities as determined by contact angle and moisture content measurements were found to be significantly increased on increasing PEG contents and molecular weights. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2677–2683, 2006     

Synthesis and characterization of biodegradable linear–hyperbranched barbell‐like poly(ethylene glycol)‐supported poly(lactic‐ran‐glycolic acid) copolymers through direct polycondensation

A series of biodegradable linear–hyperbranched barbell‐like poly(ethylene glycol) (PEG)‐supported poly(lactic‐ran‐glycolic acid) (PLGA) copolymers were synthesized with PEG, d ,l ‐lactic acid aqueous solution, glycolic acid and gluconic acid (Glu) under bulk conditions. The branching density of the hyperbranched section was varied by controlling the molar ratio of Glu to hydroxyl‐terminal groups of PEG ([Glu]/[OH] = 1, 3.5, 6.0, 8.5). Chemical structures of these copolymers were confirmed using NMR spectroscopy. The molecular weights were determined using ¹H NMR group analysis and gel permeation chromatography, both results being consistent with one another. The results of hydrolytic degradation indicate that these copolymers can degrade completely in no more than three weeks. The thermal properties were evaluated using differential scanning calorimetry and thermogravimetric analysis. The results indicate that the glass transition temperatures and melt temperatures of these copolymers are not above 50 °C. The self‐assembly behavior of the copolymers on hydrophilic surfaces was also investigated. The morphology of self‐assembly films made of the copolymers was observed using atomic force microscopy, and the results indicate that these copolymers exhibit more inhomogeneous and rough structural orientated films on a silicon wafer substrate with increasing branching densities. Due to the favorable biodegradability and biocompatibility of the PLGA and PEG, the results suggest new possibilities for these novel structural amphiphilic linear–hyperbranched barbell‐like copolymers as potential biomaterials. © 2013 Society of Chemical Industry     

Synthesis and characterization of poly(ϵ‐caprolactone)‐b‐poly(ethylene glycol) block copolymers prepared by a salicylaldimine‐aluminum complex

A series of poly(?‐caprolactone)‐b‐poly(ethylene glycol) (PCL‐b‐PEG) block copolymers with different molecular weights were synthesized with a salicylaldimine‐aluminum complex in the presence of monomethoxy poly(ethylene glycol). The block copolymers were characterized by ¹H NMR, GPC, WAXD, and DSC. The ¹H NMR and GPC results verify the block structure and narrow molecular weight distribution of the block copolymers. WAXD and DSC results show that crystallization behavior of the block copolymers varies with the composition. When the PCL block is extremely short, only the PEG block is crystallizable. With further increase in the length of the PCL block, both blocks can crystallize. The PCL crystallizes prior to the PEG block and has a stronger suppression effect on crystallization of the PEG block, while the PEG block only exerts a relatively weak adverse effect on crystallization of the PCL block. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Miscibility of block copolymers of poly(ε‐caprolactone) and poly(ethylene glycol) with poly(3‐hydroxybutyrate) as well as the compatibilizing effect of these copolymers in blends of poly(ε‐caprolactone) and poly(3‐hydroxybutyrate)

Atactic poly(3‐hydroxybutyrate) (a‐PHB) and block copolymers of poly(ethylene glycol) (PEG) with poly(ε‐caprolactone) (PCL‐b‐PEG) were synthesized through anionic polymerization and coordination polymerization, respectively. As demonstrated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) measurements, both chemosynthesized a‐PHB and biosynthesized isotactic PHB (i‐PHB) are miscible with the PEG segment phase of PCL‐b‐PEGs. However, there is no evidence showing miscibility between both PHBs and the PCL segment phase of the copolymer even though PCL has been block‐copolymerized with PEG. Based on these results, PCL‐b‐PEG was added, as a compatibilizer, to both the PCL/a‐PHB blends and the PCL i‐PHB blends. The blend films were obtained through the evaporation of chloroform solutions of mixed components. Excitingly, the improvement in mechanical properties of PCL/PHB blends was achieved as anticipated initially upon the addition of PCL‐b‐PEG. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2600–2608, 2001     

New optically active poly(amide–imide–urethane) thermoplastic elastomers derived from poly(ethylene glycol diols), 4,4′‐methylene‐bis(4‐phenylisocyanate), and a diacid based on an amino acid by a two‐step method under microwave irradiation

A new class of optically active poly(amide–imide–urethane)s (PAIUs) was synthesized via a two‐step diisocyanate route under microwave irradiation. In these reactions, 4,4′‐methylene‐bis(4‐phenylisocyanate) was reacted with bis(p‐amido benzoic acid)‐N‐trimellitylimido‐L ‐leucine and poly(ethylene glycol diol)s (PEGs), such as PEG‐400, PEG‐600, PEG‐1000, and PEG‐2000, to furnish a series of new PAIUs. The effects of different reaction conditions, such as the method of preparation (polyol or acid chain extension), the prepolymerization step (NCO‐terminated oligoamide or NCO‐terminated polyether polyol), the irradiation time and power, the reaction solvent, the soft‐segment length, and the presence or absence of reaction catalysts (e.g., triethylamine, pyridine, and dibutyltin dilaurate), on the properties of the copolymers, including the solubility, viscosity, and thermal behavior, were investigated. The resulting multiblock copolymers had inherent viscosities of 0.15–0.53 dL/g. These multiblock copolymers were optically active, thermally stable, and soluble in amide‐type solvents. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1781–1792, 2005     

Preparation and characterization of electrospun poly(ε‐caprolactone)–pluronic–poly(ε‐caprolactone)‐based polyurethane nanofibers

In this study, amphiphilic poly(ε‐caprolactone)–pluronic–poly(ε‐caprolactone) (PCL–pluronic–PCL, PCFC) copolymers were synthesized by ring‐opening copolymerization and then reacted with isophorone diisocyanate to form polyurethane (PU) copolymers. The molecular weight of the PU copolymers was measured by gel permeation chromatography, and the chemical structure was analyzed by ¹H‐nuclear magnetic resonance and Fourier transform infrared spectra. Then, the PU copolymers were processed into fibrous scaffolds by the electrospinning technology. The morphology, surface wettability, mechanical strength, and cytotoxicity of the obtained PU fibrous mats were investigated by scanning electron microscopy, water contact angle analysis, tensile test, and MTT analysis. The results show that the molecular weights of PCFC and PU copolymers significantly affected the physicochemical properties of electrospun PU nanofibers. Moreover, their good in vitro biocompatibility showed that the as‐prepared PU nanofibers have great potential for applications in tissue engineering. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43643.