Fabrication of co‐continuous poly(ε‐caprolactone)/polyglycolide blend scaffolds for tissue engineering

The apparent inability of a single biomaterial to meet all the requirements for tissue engineering scaffolds has led to continual research in novel engineered biomaterials. One method to provide new materials and fine‐tune their properties is via mixing materials. In this study, a biodegradable powder blend of poly(ε‐caprolactone) (PCL), polyglycolide (PGA), and poly(ethylene oxide) (PEO) was prepared and three‐dimensional interconnected porous PCL/PGA scaffolds were fabricated by combining cryomilling and compression molding/polymer leaching techniques. The resultant porous scaffolds exhibited co‐continuous morphologies with ～50% porosity. Mean pore sizes of 24 and 56 μm were achieved by varying milling time. The scaffolds displayed high mechanical properties and water uptake, in addition to a remarkably fast degradation rate. The results demonstrate the potential of this fabrication approach to obtain PCL/PGA blend scaffolds with interconnected porosity. In general, these results provide significant insight into an approach that will lead to the development of new composites and blends in scaffold manufacturing. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42471.     

Fabrication of PCL/β‐TCP scaffolds by 3D mini‐screw extrusion printing

Scaffolds of polycaprolactone (PCL) and PCL composites reinforced with β‐tricalcium phosphate (β‐TCP) were manufactured aiming potential tissue engineering applications. They were fabricated using a three‐dimensional (3D) mini‐screw extrusion printing, a novel additive manufacturing process, which consists in an extrusion head coupled to a 3D printer based on the Fab@Home equipment. Thermal properties were obtained by differential scanning calorimetry and thermogravimetric analyses. Scaffolds morphology were observed using scanning electron microscopy and computed microtomography; also, reinforcement presence was observed by X‐ray diffraction and the polymer chemical structure by Fourier transform infrared spectroscopy. Mechanical properties under compression were obtained by using a universal testing machine and hydrophilic properties were studied by measuring the contact angle of water drops. Finally, scaffolds with 55% of porosity and a pore size of 450 μm have shown promising mechanical properties; the β‐TCP reinforcement improved mechanical and hydrophilic behavior in comparison with PCL scaffolds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43031.     

Surface‐engineered hydroxyapatite nanocrystal/ poly(ε‐caprolactone) hybrid scaffolds for bone tissue engineering

To achieve novel polymer/bioceramic composite scaffolds for use in materials for bone tissue engineering, we prepared organic/inorganic hybrid scaffolds composed of biodegradable poly(ε‐caprolactone) (PCL) and hydroxyapatite (HA), which has excellent biocompatibility with hard tissues and high osteoconductivity and bioactivity. To improve the interactions between the scaffolds and osteoblasts, we focused on surface‐engineered, porous HA/PCL scaffolds that had HA molecules on their surfaces and within them because of the biochemical affinity between the biotin and avidin molecules. The surface modification of HA nanocrystals was performed with two different methods. Using Fourier transform infrared, X‐ray diffraction, and thermogravimetric analysis measurements, we found that surface‐modified HA nanocrystals prepared with an ethylene glycol mediated coupling method showed a higher degree of coupling (%) than those prepared via a direct coupling method. HA/PCL hybrid scaffolds with a well‐controlled porous architecture were fabricated with a gas‐blowing/particle‐leaching process. All HA/PCL scaffold samples exhibited approximately 80–85% porosity. As the HA concentration within the HA/PCL scaffolds increased, the porosity of the HA/PCL scaffolds gradually decreased. The homogeneous immobilization of biotin‐conjugated HA nanocrystals on a three‐dimensional, porous scaffold was observed with confocal microscopy. According to an in vitro cytotoxicity study, all scaffold samples exhibited greater than 80% cell viability, regardless of the HA/PCL composition or preparation method. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Morphology,wettability, and mechanical properties of polycaprolactone/hydroxyapatite composite scaffolds with interconnected pore structures fabricated by a mini‐deposition system

A new mini‐deposition system (MDS) was developed to fabricate scaffolds with interconnected pore structures and anatomical geometry for bone tissue engineering. Polycaprolactone/hydroxyapatite (PCL/HA) composites with varying hydroxyapatite (HA) content were adopted to manufacture scaffolds by using MDS with a porosity of 54.6%, a pore size of 716 μm in the x‐y plane, and 116 μm in the z direction. The water uptake ratio and compressive modulus of PCL/HA composite scaffold increase from 8 to 39% and from 26.5 to 49.8 MPa, respectively, as the HA content increases from 0 to 40%. PCL/HA composite scaffolds have better wettability and mechanical properties than pure PCL scaffold. A PCL/HA composite scaffold for mandible bone repair was successfully fabricated with both interconnected pore structures and anatomical shape to demonstrate the versatility of MDS. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Compatibilizing effect of starch‐grafted‐poly(L‐lactide) on the poly(ε‐caprolactone)/starch composites

The poly(ε‐caprolactone) (PCL)/starch blends were prepared with a coextruder by using the starch grafted PLLA copolymer (St‐g‐PLLA) as compatibilizers. The thermal, mechanical, thermo‐mechanical, and morphological characterizations were performed to show the better performance of these blends compared with the virgin PCL/starch blend without the compatibilizer. Interfacial adhesion between PCL matrix and starch dispersion phases dominated by the compatibilizing effects of the St‐g‐PLLA copolymers was significantly improved. Mechanical and other physical properties were correlated with the compatibilizing effect of the St‐g‐PLLA copolymer. With the addition of starch acted as rigid filler, the Young's modulus of the PCL/starch blends with or without compatibilizer all increased, and the strength and elongation were decreased compared with pure PCL. Whereas when St‐g‐PLLA added into the blend, starch and PCL, the properties of the blends were improved markedly. The 50/50 composite of PCL/starch compatibilized by 10% St‐g‐PLLA gave a tensile strength of 16.6 MPa and Young's modulus of 996 MPa, respectively, vs. 8.0 MPa and 597 MPa, respectively, for the simple 50/50 blend of PCL/starch. At the same time, the storage modulus of compatibilized blends improved to 2940 MPa. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Fabrication and characterization of hydrophilic poly(ε‐caprolactone)/pluronic P123 electrospun fibers

Poly(ε‐caprolactone) (PCL) has been widely investigated for tissue engineering applications because of its good biocompatibility, biodegradability, and mechanical properties; however hydrophobic nature of PCL has been a colossal obstacle toward achieving scaffolds which offer satisfactory cell attachment and proliferation. To produce highly hydrophilic electrospun fibers, PCL was blended with pluronic P123 (P123) and the resulted electrospun scaffolds physiochemical characteristics such as fiber morphology, thermal behavior, crystalline structure, mechanical properties, and wettability were investigated. Moreover molecular dynamic (MD) simulation was assigned to evaluate the blended and neat PCL/water interactions. Presence of P123 at the surface of electrospun blended fibers was detected using ATR‐FTIR analysis. P123 effectiveness in improving the hydrophilicity of the scaffolds was demonstrated by water contact angel which experienced a sharp decrease from 132° corresponding to the neat PCL to almost 0° for all blended samples. Also a steady increase in water uptake ratio was observed for blended fibers as P123 content increased. The 90/10 blend ratio had the maximum tensile strength, elongation at break and crystallinity percentage. Therefore 90/10 blend ratio of PCL/P123 can balance the mechanical properties and bulk hydrophilicity of the resulted electrospun scaffold and would be a promising candidate for tissue engineering application. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43345.     

Assessment of cell proliferation in salt‐leaching using powder (SLUP) scaffolds with penetrated macro‐pores

In this study, a salt‐leaching using powder (SLUP) scaffold with penetrated macropores was proposed to enhance cell proliferation. A SLUP scaffold is a salt‐leaching scaffold with an arbitrary pore configuration. Although SLUP scaffolds have several advantage over traditional salt‐leaching scaffolds, the cell ingrowth might be poor compared with solid freeform fabrication scaffolds, which have well‐interconnected pores. We therefore proposed SLUP scaffolds with penetrated macropores to assist the cell ingrowth. First, polycaprolactone (PCL) powders with a grain size of 63–100 μm and NaCl powders with a grain size of 100–180 μm were prepared. Next, a uniformly perforated mold was fabricated using an rapid prototyping (RP) system. Then, 500‐, 820‐, or 1200‐μm‐diameter needles were inserted into the holes of the RP mold. Subsequently, the mold was filled with a mixed powder of PCL/NaCl (30 : 70 vol %). The mold was then heated in the oven at 100°C for 30 min, and both the needles and the mold were removed from the PCL/NaCl mixture. Then, the PCL/NaCl mixture was soaked in DI water for 24 h to leach out NaCl particles and dried in a vacuum desiccator for 24 h. The porosity of fabricated scaffolds was calculated using a simple equation, and the compressive stiffness was measured using a universal testing machine. Moreover, each scaffold (10 × 10 × 10 mm³) was seeded with 100,000 Saos‐2 cells and cultured for 14 days. The cell proliferation characteristics were assessed using a CCK‐8 assay at 1, 7, and 14 days for comparison with the control scaffolds, that is, the SLUP scaffolds with no penetrated macropores. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40240.     

Evaluation of polycaprolactone − poly‐D,L‐lactide copolymer as biomaterial for breast tissue engineering

The potential of the copolymer polycaprolactone‐co‐ poly‐d ,l ‐lactic acid (PCLLA ) as a biomaterial for scaffold‐based therapy for breast tissue engineering applications was assessed. First, the synthesized PCLLA was evaluated for its processability by means of additive manufacturing (AM ). We found that the synthesized PCLLA could be fabricated into scaffolds with an overall gross morphology and porosity similar to that of polycaprolactone. The PCLLA scaffolds possessed a compressive Young's modulus (ca 46 kPa ) similar to that of native breast (0.5 ? 25 kPa ), but lacked thermal stability and underwent thermal degradation during the fabrication process. The PCLLA scaffolds underwent rapid degradation in vitro which was characterized by loss of the scaffolds' mechanical integrity and a drastic decrease in mass‐average molar mass (M _w) and number‐average molar mass (M _n) after 4 weeks of immersion in phosphate buffer solution maintained at 37 °C. The tin‐catalysed PCLLA scaffold was also found to have cytotoxic effects on cells. Although the initial mechanical properties of the PCLLA scaffolds generally showed potential for applications in breast tissue regeneration, the thermal stability of the copolymer for AM processes, biocompatibility towards cells and degradation rate is not satisfactory at this stage. Therefore, we conclude that research efforts should be geared towards fine‐tuning the copolymer synthesizing methods. © 2016 Society of Chemical Industry     

Surface‐modified pliable PDLLA/PCL/β‐TCP scaffolds as a promising delivery system for bone regeneration

Surface‐modified poly(d , l ‐lactide)/polycaprolactone/β‐tricalcium phosphate complex scaffold was fabricated in this study and we hypothesized that pliable and mechanical strong scaffold would be achieved by regulation of ternary compositions; while superficial modification strategy conduced to preserve and controlled‐release of bioactive growth factors. Properties of the composite scaffolds were systematically investigated, including mechanical properties, surface morphology, porosity, wettability, and releasing behavior. Moreover, the representative cytokine, recombinant human bone morphogenetic protein‐2 (rhBMP‐2), was loaded and implanted into muscular pouch of mouse to assess bone formation in vivo. Improved osteogenesis was achieved ascribed to both amplified β‐tricalcium phosphate (β‐TCP) content and retarded initial burst release. Particularly, scaffold doped with hydroxypropyl methylcellulose (HPMC) displayed optimal osteogenic capability. The results indicated that the PDLLA/PCL/β‐TCP complex scaffold along with HPMC‐coating and rhBMP‐2 loading was a promising candidate for bone regeneration. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40951.     

Fabrication of LaCl3‐containing nanofiber scaffolds and their application in skin wound healing

Poly(?‐caprolactone) (PCL)/gelatin (GE) nanofiber scaffolds with varying concentrations of lanthanum chloride (LaCl₃, from 0 to 25 mM) were fabricated by electrospinning. The scaffolds were characterized by scanning electron microscopy, contact angle and porosity measurements, mechanical strength tests, and in vitro degradation studies. In vitro cytotoxicity and cell adhesion and proliferation studies were performed to assess the biocompatibility of the scaffolds, and in vivo wound healing studies were conducted to assess scaffold applications in the clinic. All prepared scaffolds were noncytotoxic, and the growth of adipose tissue–derived stem cells on LaCl₃‐containing scaffolds was better than on the pure PCL/GE scaffold. Cell proliferation studies showed the greatest cell growth in the PCL/GE/LaCl₃ scaffolds. Further, in vivo studies proved that the PCL/GE/LaCl₃ scaffolds can promote wound healing. The results suggest that nanofiber scaffolds containing LaCl₃ promote cell proliferation and have good biocompatibility, and thus potential for application in the treatment of skin wounds. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46672.     

Fabrication and biocompatibility of porously bioactive scaffold of nonstoichiometric apatite and poly(ε‐caprolactone) nanocomposite

Bioactive nanocomposite of nonstoichiometric apatite (ns‐AP) and poly(ε‐caprolactone) (PCL) was synthesized and its porous scaffold was fabricated. The results show that the hydrophilicity and cell attachment ratio on the composite surface improved with the increase of ns‐AP content in PCL. The composite scaffolds with 60 wt % ns‐AP content contained open and interconnected pores ranging in size from 200 to 500 μm and exhibit a porosity of around 80%. In addition, proliferation of MG₆₃ cells on the composite scaffolds significantly increased with the increase of ns‐AP content, and the level of alkaline phosphatase (ALP) activity and nitric oxide (NO) production of the cells cultured on the composite scaffold were higher than that of PCL at 7 days, revealing that the composite scaffolds had excellent in vitro biocompatibility and bioactivity. The composite scaffolds were implanted into rabbit mandible defects, the results suggest that the introduction of ns‐AP into PCL enhanced the efficiency of new bone formation, and the ns‐AP/PCL composite exhibited in vivo good biocompatibility and osteogenesis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Quercetin and curcumin in nanofibers of polycaprolactone and poly(hydroxybutyrate‐co‐hydroxyvalerate): Assessment of in vitro antioxidant activity

Polymeric nanofibers are materials that can be used as scaffolds in tissue engineering. Quercetin and curcumin are antioxidants because of scavenge free radicals and chelate metal ions properties, protecting tissues of lipid peroxidation. The objective of this study was to develop a scaffold with potential antioxidant activity that was produced from nanofibers consisting of polycaprolactone (PCL) and a blend of PCL/poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHB‐HV) with the addition of quercetin or curcumin as the bioactive compound. Curcumin and quercetin were integrated into the solution at a concentration of 3%. The electrospun nanofibers were characterized using calorimetry and thermogravimetric analysis, and the addition of bioactive compounds did not alter the thermal properties of the biomaterial. The antioxidant activity of scaffolds with the active compounds was evaluated by hydrate 2,2‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonic acid) diammonium salt (ABTS) methods. The scaffolds with PCL and PCL/PHB‐HV blend with quercetin exhibited higher antioxidant activity than curcumin with both methods. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43712.     

Fabrication and Evaluation of Polycaprolactone–Poly(hydroxybutyrate) or Poly(3‐Hydroxybutyrate‐co‐3‐Hydroxyvalerate) Dual‐Leached Porous Scaffolds for Bone Tissue Engineering Applications

Polycaprolactone (PCL) blend with poly(hydroxybutyrate) (PHB) or poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) dual‐leached scaffolds are prepared by using the solvent casting and salt–polymer‐leaching technique. The blending of the PHB and PHBV in PCL scaffolds results in decreased porosities of the scaffolds, and the water absorption capacities of the scaffolds also decrease. The compressive modulus of the PCL–PHB and PCL–PHBV dual‐leached scaffolds is greatly increased by the blending of PHB or PHBV matrix. An indirect cytotoxicity evaluation of all scaffolds with mouse fibroblastic cells (L929) and mouse calvaria‐derived preosteoblastic cell (MC3T3‐E1) indicates that all dual‐leached scaffolds are posed as nontoxic to cells. Both PCL–PHB and PCL–PHBV dual‐leached scaffolds are supported by the attachment of MC3T3‐E1 at significantly higher levels to tissue culture polystyrene plate (TCPS) and are able to support the proliferation of MC3T3‐E1 at higher levels to that cells on TCPS and PCL scaffolds. For mineralization, cells cultured on surfaces of PCL–PHB and PCL–PHBV dual‐leached scaffolds show higher mineral deposition than on TCPS and PCL scaffold.

     

Poly(ε‐caprolactone) composite scaffolds loaded with gentamicin‐containing β‐tricalcium phosphate/gelatin microspheres for bone tissue engineering applications

In this study, novel poly(ε‐caprolactone) (PCL) composite scaffolds were prepared for bone tissue engineering applications, where gentamicin‐loaded β‐tricalcium phosphate (β‐TCP)/gelatin microspheres were added to PCL. The effects of the amount of β‐TCP/gelatin microspheres added to the PCL scaffold on various properties, such as the gentamicin release rate, biodegradability, morphology, mechanical strength, and pore size distribution, were investigated. A higher amount of filler caused a reduction in the mechanical properties and an increase in the pore size and led to a faster release of gentamicin. Human osteosarcoma cells (Saos‐2) were seeded on the prepared composite scaffolds, and the viability of cells having alkaline phosphatase (ALP) activity was observed for all of the scaffolds after 3 weeks of incubation. Cell proliferation and differentiation enhanced the mechanical strength of the scaffolds. Promising results were obtained for the development of bone cells on the prepared biocompatible, biodegradable, and antimicrobial composite scaffolds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40110.     

Structure and properties of a compatible starch‐PCL composite using p‐phthaloyl chloride‐based prepolymer

Biodegradable composites from starch and hydrophobic polymer usually show poor compatibility. A novel p‐phthaloyl chloride‐based prepolymer (PCP) compatibilizer based on p‐phthaloyl chloride and polycaprolactone (PCL) diol (2000) was synthesized successfully and the chemical structure was characterized by Fourier transform infrared spectra and ¹H nuclear magnetic resonance (NMR). The PCP compatiblizer was mixed with starch granules to form a coating layer, and then the coated starch granules were melt‐compounded with PCL plastic to prepare compatible starch‐PCL composites with enhanced properties. The structural, mechanical, thermal properties, and water absorption of the composites were then investigated. It was found that the composites containing the PCP compatibilizer showed better interfacial interaction and compatibility between starch and PCL domains compared to the pure starch‐PCL composite, which led to the improved mechanical properties of the composites. The results were attributed to the ester linkage between the PCP compatibilizer and starch as well as the strong physical crosslinking between the PCP compatibilizer and PCL plastic through PCL‐PCL crystallinity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45400.     

Preparation and characterization of poly(L‐lactide)/ poly(ϵ‐caprolactone) fibrous scaffolds for cartilage tissue engineering

Polyblend fibrous scaffolds in mass ratios of 100/0, 90/10, 80/20, and 70/30 from poly(L ‐lactide) (PLLA) and poly(?‐caprolactone) (PCL) for cartilage tissue engineering were prepared in three steps: gelation, solvent exchanging, and freeze‐drying. Effects of the blend ratio, the exchange medium, and the operating temperature on the morphology of scaffolds were investigated by SEM. PLLA/PCL scaffolds presented an ultrafine fibrous network with the addition of a “small block” structure. Smooth and regular fibrous networks were formed when ethanol was used as the exchange medium. Properties of the scaffolds, such as thermal and mechanical properties, were also studied. The results suggested that the compressive modulus declined as PCL amount increased. The incorporation of PCL effectively contributed to reduce the rigidity of PLLA. Bovine chondrocytes were seeded onto PLLA/PCL scaffold. Cells attached onto the fibrous network and their morphology was satisfactory. This polyblend fibrous scaffold will be a potential scaffold for cartilage tissue engineering. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1676–1684, 2004     

Integrated three‐dimensional fiber/hydrogel biphasic scaffolds for periodontal bone tissue engineering

Combining a tissue engineering scaffold made of a load‐bearing polymer with a hydrogel represents a powerful approach to enhancing the functionalities of the resulting biphasic construct, such as its mechanical properties or ability to support cellular colonization. This research activity was aimed at the development of biphasic scaffolds through the combination of an additively manufactured poly(?‐caprolactone) (PCL) fiber construct and a chitosan/poly(γ‐glutamic acid) polyelectrolyte complex hydrogel. By investigating a set of layered structures made of PCL or PCL/hydroxyapatite composite, biphasic scaffold prototypes with good integration of the two phases at the macroscale and microscale were developed. The biphasic constructs were able to absorb cell culture medium up to 10‐fold of their weight, and the combination of the two phases had a significant influence on compressive mechanical properties compared with hydrogel or PCL scaffold alone. In addition, due to the presence of chitosan in the hydrogel phase, biphasic scaffolds exerted a broad‐spectrum antibacterial activity. The developed biphasic systems appear well suited for application in periodontal bone regenerative approaches in which a biodegradable porous structure providing mechanical stability and a hydrogel phase functioning as absorbing depot of endogenous proteins are simultaneously required. © 2016 Society of Chemical Industry     

Reinforcement of electrospun poly(ε‐caprolactone) scaffold using diopside nanopowder to promote biological and physical properties

Considerable efforts have been devoted toward the development of electrospun scaffolds based on poly(ε‐caprolactone) (PCL) for bone tissue engineering. However, most of previous scaffolds have lacked the structural and mechanical strength to engineer bone tissue constructs with suitable biological functions. Here, we developed bioactive and relatively robust hybrid scaffolds composed of diopside nanopowder embedded PCL electrospun nanofibers. Incorporation of various concentrations of diopside nanopowder from 0 to 3 wt % within the PCL scaffolds notably improved tensile strength (eight‐fold) and elastic modulus (two‐fold). Moreover, the addition of diopside nanopowder significantly improved bioactivity and degradation rate compared to pure PCL scaffold which might be due to their superior hydrophilicity. We investigated the proliferation and spreading of SAOS‐II cells on electrospun scaffolds. Notably, electrospun PCL‐diopside scaffolds induced significantly enhanced cell proliferation and spreading. Overall, we concluded that PCL‐diopside scaffold could potentially be used to develop clinically relevant constructs for bone tissue engineering. However, the extended in vivo studies are essential to evaluate the role of PCL‐diopside fibrous scaffolds on the new bone growth and regeneration. Therefore, in vivo studies will be the subject of our future work. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44433.     

Biodegradable polycaprolactone/cuttlebone scaffold composite using salt leaching process

We prepared biodegradable polycaprolactone/cuttlebone scaffold composite by salt leaching process. In the first step, a co-continuous blend of biodegradable materials, polycaprolactone (PCL) and cuttlebone (CB), and an amount of sodium chloride salt particles were mixed using a stirrer. Next, the extraction of mineral salts using de-ionized distilled water was performed using a biodegradable PCL/CB scaffold with fully interconnected pores. Finally, the durable morphology of the scaffolds was fabricated by freeze-drying process at ?53 °C for 24 hrs in a vacuum. In addition, the quadrilateral pres ranged from about 250 to 300 ??m in diameter. Scanning electron microscopy (SEM) and mercury intrusion porosimeter techniques were carried out to characterize the pore morphology. By increasing the CB and sodium chloride salt particle content, the number of interconnected pores, material properties, and pore morphology were dramatically changed. The average compressive strengths (load at 50% strain) of the different porous PCL/CB scaffolds were found to decrease from 133 to about 79 (load at 50% strain, gf) with an increase in porosity. The values of the porosity increased as the sodium chloride salt volume fraction increased     

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.