Polycaprolactone Blends Research Articles

Polarized polymer light-emitting electrochemical cells using polyfluorene and polycaprolactone blend film by floating-film transfer method

Abstract Sandwich-type structured polarized Polymer Light-emitting Electrochemical Cells (PLECs) of poly(9,9-dioctylfluorene) (PFO) successfully fabricated by combination of floating-film transfer method (FTM) and Post-blending ionic liquid (IL) procedure. An ion-solvating polymer, polycaprolactone (PCL), was blended in PFO for improving IL penetration. The PFO:PCL film showed clear optical dichroism due to the PFO backbone orientation. The IL, 1-Ethyl-3-methylimidazolium (trifluoromethylsulfonyl)imide (EMIm-TFSI), easily post-blended into the PFO:PCL blend FTM film without disordering PFO backbone orientation. The fabricated thickness varied PLECs with ITO anode and aluminum cathode were demonstrated distinct anisotropy, whole device area emission and low turn-on voltage compared to PLEDs.

Nanoimprinting of Crosslinked Polyurethane / Polycaprolactone Blends: Scratch Recovery of Surface Topographies.

Scratch recovery of micro-nano-patterned polymer surfaces extends the service life of products that require tunable surface properties and contributes to more sustainable development. Scratch recovery has been widely studied in bulk and 4D-printed polymers via intrinsic self-healing mechanisms. Existing studies on self-healing of micro/nano-scale polymeric surfaces are limited to the recovery of controlled tensile or compressive strain. Scratch recovery requires material transport to close the gap created by a scratch. Here, for the first time, scratch recovery of thermally nanoimprinted polymer surfaces in a heterogeneous polymer is reported. A blend of Polyurethane (TPU) and poly(caprolactone) (PCL) with selectively crosslinked TPU imparts shape-memory properties, and the uncrosslinked PCL retains chain mobility for molecular diffusion during scratch recovery. Scratch recovery of nanoimprinted micro-pillars has been achieved spontaneously and completely by heat and without any pressure input. The healing temperature is determined to be the melting point of PCL at 60°C. Rapid recovery is also achieved at 60 s with complete closure of scratch width of 5µm and topography recovery of the nanoimprinted micro-pillars.

Enhancing bone repair through improved angiogenesis and osteogenesis using mesoporous silica nanoparticle-loaded Konjac glucomannan-based interpenetrating network scaffolds

We have fabricated and characterized novel bioactive nanocomposite interpenetrating polymer network (IPN) scaffolds to treat bone defects by loading mesoporous silica nanoparticles (MSNs) into blends of Konjac glucomannan, polyvinyl alcohol, and polycaprolactone. By loading MSNs, we developed a porous nanocomposite scaffold with mechanical strengths comparable to cancellous bone. In vitro cell culture studies proved the cytocompatibility of the nanocomposite scaffolds. RT-PCR studies confirmed that these scaffolds significantly upregulated major osteogenic markers. The in vivo chick chorioallantoic membrane (CAM) assay confirmed the proangiogenic activity of the nanocomposite IPN scaffolds. In vivo studies were performed using Wistar rats to evaluate the scaffolds' compatibility, osteogenic activity, and proangiogenic properties. Liver and renal function tests confirmed that these scaffolds were nontoxic. X-ray and μ-CT results show that the bone defects treated with the nanocomposite scaffolds healed at a much faster rate compared to the untreated control and those treated with IPN scaffolds. H&E and Masson's trichrome staining showed angiogenesis near the newly formed bone and the presence of early-stage connective tissues, fibroblasts, and osteoblasts in the defect region at 8 weeks after surgery. Hence, these advantageous physicochemical and biological properties confirm that the nanocomposite IPN scaffolds are ideal for treating bone defects.

Enhanced compatibility and toughness of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate)/polycaprolactone blends by ring‐opening polymerization and hydrogen bonding of epoxy‐terminated hyperbranched polyester

AbstractMelt extrusion process was followed in order to improve the high crystallinity and poor toughness of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) blend materials. It was achieved by the incorporation of epoxy‐terminated hyperbranched polyester (EHBP) elastomer into PHBV and polycaprolactone (PCL). EHBP cross‐links PHBV and PCL through ring‐opening polymerization of epoxy‐terminated and carboxyl groups. The mass percentages of EHBP in the PHBV/PCL blends are 1, 2, 3, and 4mass%, which are expressed as 1, 2, 3, and 4 phr in the following text. Therefore, when the EHBP content was 3 phr, the Young's modulus and tensile strength of the blends are increased to 750 and 15 MPa, respectively, which was comparable to the biodegradable polymers used for packaging. Simultaneously, compatibility between PHBV and PCL has been improved and the particle size reduction of blends can be obviously observed in scanning electron microscope (SEM) images. Dynamic mechanical analysis (DMA) analysis revealed that PHBV and PCL showed improved compatibility with each other by the addition of EHBP. Differential scanning calorimetry (DSC) revealed that the decrease of crystallinity of the blend was consistent with the increase in mechanical properties. Additionally, all the bio‐blends show good thermal stability. Food overall migration studies showed that the amount of migration of composite materials in contact with food was also far lower than the national standard value. Therefore, PHBV/PCL/EHBP blends are expected to be used in the field of food packaging.

Development of Cerium Oxide-Laden GelMA/PCL Scaffolds for Periodontal Tissue Engineering.

This study investigated gelatin methacryloyl (GelMA) and polycaprolactone (PCL) blend scaffolds incorporating cerium oxide (CeO) nanoparticles at concentrations of 0%, 5%, and 10% w/w via electrospinning for periodontal tissue engineering. The impact of photocrosslinking on these scaffolds was evaluated by comparing crosslinked (C) and non-crosslinked (NC) versions. Methods included Fourier transform infrared spectroscopy (FTIR) for chemical analysis, scanning electron microscopy (SEM) for fiber morphology/diameters, and assessments of swelling capacity, degradation profile, and biomechanical properties. Biological evaluations with alveolar bone-derived mesenchymal stem cells (aBMSCs) and human gingival fibroblasts (HGFs) encompassed tests for cell viability, mineralized nodule deposition (MND), and collagen production (CP). Statistical analysis was performed using Kruskal-Wallis or ANOVA/post-hoc tests (α = 5%). Results indicate that C scaffolds had larger fiber diameters (~250 nm) compared with NC scaffolds (~150 nm). NC scaffolds exhibited higher swelling capacities than C scaffolds, while both types demonstrated significant mass loss (~50%) after 60 days (p < 0.05). C scaffolds containing CeO showed increased Young's modulus and tensile strength than NC scaffolds. Cells cultured on C scaffolds with 10% CeO exhibited significantly higher metabolic activity (>400%, p < 0.05) after 7 days among all groups. Furthermore, CeO-containing scaffolds promoted enhanced MND by aBMSCs (>120%, p < 0.05) and increased CP in 5% CeO scaffolds for both variants (>180%, p < 0.05). These findings underscore the promising biomechanical properties, biodegradability, cytocompatibility, and enhanced tissue regenerative potential of CeO-loaded GelMA/PCL scaffolds for periodontal applications.

Synthesis and Viscoelastic Properties of Polycaprolactone/Polyvinylidene Fluoride/Nanohydroxyapatite Composite Scaffolds

AbstractObtaining a polymer nanocomposite with optimum viscoelastic, thermal, and biocompatibility properties is the main objective when designing nanocomposite systems with potential applications in tissue engineering. For this purpose, a blend of Polycaprolactone (PCL) and Polyvinylidene fluoride (PVDF) in an 85/15 weight ratio, along with a nanocomposite reinforced by nanohydroxyapatite (nHA) particles, is fabricated using a solution casting method in a mold. The impact of nHA content on crystallinity, viscoelastic properties, thermal stability, and the properties–structure relationship of nanocomposites is evaluated using scanning electron microscopy (SEM). Dynamic mechanical thermal (DMTA) analysis is used to determine the William–Landel–Ferry (WLF) constants and the effect of nHA on the nanocomposite's viscoelastic behavior. The PCL/15PVDF/0.5 wt% nHA exhibits the maximum thermal stability (40% residual char value) and 95% increase in storage modulus at 90 °C (rubbery region) in comparison with PCL/15PVDF blend. Water contact angle (WCA) and biocompatibility tests are conducted on the PCL/15PVDF blend and nanocomposite scaffolds to design appropriate nanocomposite systems with potential applications in tissue engineering. The high hydrophilic properties are assigned to PCL/15PVDF/0.5 wt% nHA with a WCA of 67.5°. Finally, in vitro cell culture confirmed 0.5 wt% nHA significantly improves cell adhesion and cytotoxicity with MG‐63 cells.

Electrospun scaffolds based on a PCL/starch blend reinforced with CaO nanoparticles for bone tissue engineering

Electrospun nanocomposite scaffolds with improved bioactive and biological properties were fabricated from a blend of polycaprolactone (PCL) and starch, and then combined with 5 wt% of calcium oxide (CaO) nanoparticles sourced from eggshells. SEM analyses showed scaffolds with fibrillar morphology and a three-dimensional structure. The hydrophilicity of scaffolds was improved with starch and CaO nanoparticles, which was evidenced by enhanced water absorption (3500 %) for 7 days. In addition, PCL/Starch/CaO scaffolds exhibited major degradation, with a mass loss of approximately 60 % compared to PCL/Starch and PCL/CaO. The PCL/Starch/CaO scaffolds decreased in crystallinity as intermolecular interactions between the nanoparticles retarded the mobility of the polymeric chains, leading to a significant increase in Young's modulus (ca. 60 %) and a decrease in tensile strength and elongation at break, compared to neat PCL. SEM-EDS, FT-IR, and XRD analyses indicated that PCL/Starch/CaO scaffolds presented a higher biomineralization capacity due to the ability to form hydroxyapatite (HA) in their surface after 28 days. The PCL/Starch/CaO scaffolds showed attractive biological performance, allowing cell adhesion and viability of M3T3-E1 preosteoblastic cells. In vivo analysis using a subdermal dorsal model in Wistar rats showed superior biocompatibility and improved resorption process compared to a pure PCL matrix. This biological analysis suggested that the PCL/Starch/CaO electrospun mats are suitable scaffolds for guiding the regeneration of bone tissue.

Design on thermal-mechanism coordination for binding reinforcing mesh based on shape memory polymer

The traditional rebar binding devices require complex drive and transmission mechanisms, which leads to large volume and complex structure. In this paper, a cylindrical thermoplastic shape memory polymer (SMP) fixture is proposed to verify the rebar binding method of thermal-mechanism coordination. The SMP fixture is manufactured by the injection molding technology through selecting suitable-ratio Polylactic acid and Polycaprolactone (PCL) blend materials. Besides, an additional auxiliary device is presented to overcome the incomplete recovery disadvantage existing in the thermoplastic SMP and completely achieve binding the rebar. On this base, two different binding methods are proposed to compare the mechanical performance after fixing the rebar, and the external force/thermal contributions are tested and discussed in detail. The tested results show that the binding contribution of heat could reach 70% while the binding contribution of external force could reach 30% above the transition temperature (Tg ). The maximum tensile force that the binding rebar can withstand under the thermal-mechanism coordination action could reach up to 657.7 N, which is higher than the maximum tensile force of the wire binding. In addition, the maximum friction force between rebar and notches of fixture could reach up to 94.1 N, which further verifies the feasibility of thermal-mechanism coordination for binding reinforcing mesh based on SMP fixture.

Healing Process Affected by Morphology of PCL/Epoxy Blends

In this study, a blend of epoxy and polycaprolactone (PCL) was prepared to investigate its ‎properties. Different weight percentages of thermoplastic PCL (0.25, 0.5, 1, 2 wt%) were ‎combined with epoxy coatings. The final morphology revealed PCL scattered as spherical ‎particles within the epoxy phase, which was functioning as a continuous matrix. The coating ‎showed toughness and rigidity when it had fully cured. The PCL phase had a special behavior ‎when heated, called "bleeding," in which it filled any open surfaces of its own volition. By ‎using molten PCL to fill in cracks, this property can be used for self-healing applications. The ‎self-healing efficacy of blends with different PCL contents was assessed. The self-healing ‎efficacy of the various mixes was determined by dividing the width of the self-healed crack by ‎the width of the original crack. The results showed that the highest thermal-mending efficiencies, ‎reaching 100%, were achieved with a PCL/epoxy blend containing co-continuous phases, ‎specifically at a 1 wt.% PCL content. Fourier-transform infrared (FTIR) analysis indicated that ‎there was physical interaction between the epoxy and PCL phases, but no chemical bonding ‎occurred between them.‎

Nanoengineered oxygen-releasing polymeric scaffold with sustained release of dexamethasone for bone regeneration

Maintaining the continuous oxygen supply and proper cell growth before blood vessel ingrowth at the bone defect site are considerably significant issues in bone regeneration. Oxygen-producing scaffolds can supply oxygen and avoid hypoxia leading to expedited bone regeneration. Herein, first oxygen-producing calcium peroxide nanoparticles (CPO NPs) are synthesized, and subsequently, the various amounts of synthesized CPO NPs (0.1, 0.5, and 1 wt/v%) loaded in the scaffold composite, which is developed by simple physical blending of chitosan (CS) and polycaprolactone (PCL) polymers. To deliver the synergistic therapeutic effect, dexamethasone (DEX), known for its potential anti-inflammatory and osteogenic properties, is loaded into the nanocomposite scaffolds. The extensive physicochemical characterizations of nanocomposite scaffolds confirm the successful loading of CPO NPs, adequate porous morphology, pore size, hydrophilicity, and biodegradability. In vitro, biological studies support the antibacterial, hemocompatible, and cytocompatible (MG-63 and MC3T3-E1 cells) nature of the material when tested on respective cells. Field emission scanning electron microscopy and energy-dispersive x-ray spectroscopy confirm the successful biomineralization of the scaffolds. Scaffolds also exhibit the sustained release of DEX and efficient protein adsorption. This study revealed that a nanoengineered scaffold loaded with CPO NPs (PCL/CS/DEX/CPO 3) is a suitable candidate for bone tissue regeneration.

Polycaprolactone/graphene oxide/magnesium oxide as a novel composite scaffold for bone tissue engineering: Preparation and physical/biological assessment

Mechanically robust biocomposite scaffolds were fabricated by the electrospinning method for bone tissue engineering using a blend of polycaprolactone (PCL), and graphene oxide (GO) with magnesium oxide (MgO) nanoparticles. Physicochemical characteristics including morphology, tensile strength, swelling behavior, biodegradability, contact angle, cell viability, alkaline phosphatase (ALP) activity, mineralization ability, and osteogenic gene expression of the scaffolds were characterized. The addition of small amounts of GO and MgO nanoparticles significantly improved the morphological and mechanical properties of the PCL scaffold. The hydrophilicity, swelling ratio, and biodegradability of the developed composite scaffolds were improved. The PCL/GO/MgO scaffold demonstrated excellent biocompatibility and in-vitro biological performance with adipose-derived mesenchymal stem cells. Cell attachment, proliferation, ALP activity, mineral deposition, and osteogenesis-related gene expression were enhanced when compared to the pure PCL and PCL/GO scaffolds. Simultaneous incorporation of GO and MgO nanoparticles at a concentration of 2 wt% dramatically increased the differentiation of MSCs into osteoblasts. These findings may suggest that the hydrophilic properties and high protein adsorption of PCL/GO/MgO scaffold can stimulate cell proliferation, and nucleation to help improve bone mineralization.

Biodegradable and gas barrier polylactic acid/star-shaped polycaprolactone blend films functionalized with a bio-sourced polyelectrolyte coating

This work aims at improving and disclosing new properties of films based on polylactic acid (PLA) and a star-shaped polycaprolactone (PCL). Indeed, previous works demonstrated that the presence of ad-hoc synthesized PCL, characterized by low molecular weight and carboxyl end groups (coded as PCL-COOH), improves the elongation at break of the films compared to that of neat PLA and increases their functionality. To further improve the properties of the system, alternating layers of chitosan (CH) and DNA were deposited on the surface applying a Layer-by-Layer (LbL) technique. This method was chosen because it allows the properties of the system to be modified without affecting the specific features of the bulk. In addition, the LbL technique is easily scalable and environmentally friendly because it is based on the use of an aqueous solution of two biomaterials, namely DNA and CH, which are not only derived from renewable sources but are also biocompatible and biodegradable. IR measurements on model silicon substrates subjected to the same treatment as the films, pointed out a linear growth of the proposed LbL assembly. Indeed, FE-SEM measurements highlighted the deposition of a uniform coating. The presence of the CH/DNA assembly reduced the oxygen permeability under both dry and humid (50% R.H.) conditions when compared to the uncoated film. In addition, the coating had no relevant effect on the hydrolytic and enzymatic degradation of the system, so that the biodegradability of the film was maintained.

Valorising Cassava Peel Waste Into Plasticized Polyhydroxyalkanoates Blended with Polycaprolactone with Controllable Thermal and Mechanical Properties

Approximately 99% of plastics produced worldwide were produced by the petrochemical industry in 2019 and it is predicted that plastic consumption may double between 2023 and 2050. The use of biodegradable bioplastics represents an alternative solution to petroleum-based plastics. However, the production cost of biopolymers hinders their real-world use. The use of waste biomass as a primary carbon source for biopolymers may enable a cost-effective production of bioplastics whilst providing a solution to waste management towards a carbon–neutral and circular plastics economy. Here, we report for the first time the production of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with a controlled molar ratio of 2:1 3-hydroxybutyrate:3-hydroxvalerate (3HB:3HV) through an integrated pre-treatment and fermentation process followed by alkaline digestion of cassava peel waste, a renewable low-cost substrate, through Cupriavidus necator biotransformation. PHBV was subsequently melt blended with a biodegradable polymer, polycaprolactone (PCL), whereby the 30:70 (mol%) PHBV:PCL blend exhibited an excellent balance of mechanical properties and higher degradation temperatures than PHBV alone, thus providing enhanced stability and controllable properties. This work represents a potential environmental solution to waste management that can benefit cassava processing industries (or other crop processing industries) whilst developing new bioplastic materials that can be applied, for example, to packaging and biomedical engineering.Graphical

Airbrushed nanofibers with bioactive core and antibacterial shell for wound healing application

Acute and chronic wounds are vulnerable to infection and delayed healing and require critical care and advanced wound protection. To overcome the challenges, dual therapy of antibacterial and growth factors will be a novel wound care strategy. The present study explores airbrushed core–shell nanofiber for dual delivery of epidermal growth factor (EGF) and amoxicillin (AMOX) in a sustained manner. A blend of polycaprolactone (PCL)-polyethylene oxide (PEO) was used to prepare the shell compartment for amoxicillin loading and poly-DL-lactide (PDLLA) core for EGF loading by using a customized airbrush setup. Characterization result shows a uniform distribution of nanofibers ranging between 200 and 500 nm in diameter. Amoxicillin loading in the shell compartment offers an initial burst release followed by a sustained release for up to 14 days. Whereas EGF in the core part shows a continuous sustained release throughout the release study.In-vitrostudy indicates the biocompatibility of EGF-AMOX loaded core–shell nanofibers with human dermal fibroblast cell (HDF) cells and a higher cellular proliferation compared to control samples. Gene expression data show an increase in fold change of collagen I and tropoelastin expression, indicating the regenerative properties of EGF-AMOX encapsulated nanofiber. The combination of bioactive core (EGF) and antibiotic shell (amoxicillin) in an airbrushed nanofibrous scaffold is a novel approach, which is the first time explored to deliver sustainable therapy to treat skin wounds. Our results demonstrate that PCL-PEO-Amoxicillin/PDLLA-EGF-loaded core–shell nanofibers are promising dual therapy scaffolds to deliver effective skin wound care, with the possibility of direct deposition on the wound.

Crystallization in blend of polycaprolactone and high molecular weight polyethylene oxide

The concentration distribution in blend of polyethylene oxide (PEO)/polycaprolactone (PCL) and subsequent crystallization were investigated with differential scanning calorimetry, in-situ small angle X-ray scattering and wide angle X-ray scattering. By using PEOs with a molecular weight of 1 × 106 g/mol (PEO1M) and 1 × 105 g/mol (PEO100k), respectively, it is revealed that in initial blend the concentration of PEO1M in PEO-rich region is higher than that determined by miscibility. This non-equilibrium distribution induced by crystallization is maintained after melting, since slow relaxation of PEO1M hinders the redistribution process. Crystallization behavior of blend with 25 % of PEO1M at different melting temperatures was further investigated. The crystallinity shows no dependence on melting temperature, while the long period of PEO1M decreases continuously when melting temperature exceeds 140 °C. This decrease indicates more PCL chains diffuse into PEO-rich regions with increasing temperature and molten PCL chains reduce the entanglement number of PEO1M as solvent. Moreover, the periodicity of PEO1M lamellae becomes worse when crystallization proceeds faster, which is related to slower exclusion of PCL chains.

LDPE/PCL nanofibers embedded chlorhexidine diacetate for potential antimicrobial applications

In this study, we described the process of developing antimicrobial nanofibers using a solution-based electrospinning technique. The nanofibers were composed of a 40:60 blend of low-density polyethylene (LDPE) and polycaprolactone (PCL), loaded with chlorhexidine diacetate (CHD).The diameter of the nanofibers was measured for LDPCL (235 nm), but it changed to 148, 194, and 325 nm for LDPCL-CHD 1%, 3%, and 5%, respectively. The hydrophilic properties of the nanofibers were significantly improved by incorporating CHD. Also, the contact angle was reduced from 116 ± 5° to 37 ± 2°. The CHD was released from the nanofibers by an initial immediate release and then by extended-release. The released CHD from the nanofibers was found to effectively reduce the formation of biofilms when exposed to microorganisms such as S. aureus and E. coli compared to the control group (LDPCL). The drug-loaded nanofibers were found to be non-cytotoxic when incubated with L929 fibroblast cells for the duration of 24 and 72 h. The study findings suggest that antimicrobial nanofibers have potential applications in preventing implant-related infections caused by (S. aureus and E. coli).

Enhanced dielectric and mechanical properties of polylactic acid/polycaprolactone blends by introducing double‐layer carbon nanofillers

AbstractTo overcome the issues of poor toughness and low dielectric constant associated with PLA, which limit its application in the electronics industry, we introduced an insulating polydopamine (PDA) layer on the surface of core‐shell nickel‐coated carbon nanotube (Ni‐CNT) and nickel‐coated graphene (Ni‐GRA). Through a double‐layer structural design approach, we successfully prepared polylactic acid (PLA)/polycaprolactone (PCL) blends that exhibit high dielectric constant (ε’) and low dielectric loss (tanδ). This innovative design led to impressive impact strengths of 29.41 kJ/m2 for PLA/PCL/4Ni‐GRAs and 22.54 kJ/m2 for PLA/PCL/4Ni‐CNTs. PDA enhanced the interfacial interactions between the filler and matrix, which improved the dispersion of Ni‐CNTs and Ni‐GRAs and contributed to the mechanical properties of the PLA/PCL blends. Simultaneously, PLA/PCL/4Ni‐CNTs and PLA/PCL/4Ni‐GRAs exhibited commendable integrated dielectric properties. The PDA@fillers form microcapacitors with the polymer matrix and the conductive Ni layer enhances ε’ and reduces the conductivity difference between fillers. Furthermore, the insulating PDA layer contributed to improved dispersion, inhibition of charge carrier migration, and reduction in tanδ. At 1000 Hz, the ε′ of PLA/PCL/4Ni‐CNTs and PLA/PCL/4Ni‐GRAs increased to 88.3 and 124.6, respectively, and the tanδ values remained below 1, indicating minimal dielectric loss. This provides a promising direction for eco‐friendly materials with enhanced dielectric and mechanical properties.

Effects of polycaprolactone viscosity on morphology, mechanical properties, water uptake, and cellular viability in poly(3‐hydroxybutyrate)/polycaprolactone blends for tissue engineering

AbstractIn this study, two polycaprolactones (PCLs) with different molar masses were evaluated regarding their influence on the melt processability, morphology viscoelastic and mechanical properties, water uptake, and fibroblast and pre‐osteoblast viability of poly(3‐hydroxybutyrate)/polycaprolactone (PHB/PCL) blends. PHB/PCL blends were prepared in a mixing chamber following 90/10 and 70/30 ratios and later compression molded. The torque rheometry results show that the blends' processability is influenced by the ratio and molar mass of the PCL used in its obtaining, those being more strongly affected by the PCL with lower molar mass. The results indicate that the polymeric blend was immiscible in any proportion and molar mass of PCL used. The blends showed a sea‐island morphology in which the diameter of the dispersed phase depended on the composition. In general, even though the molar mass of PCL differed, the blends showed similar behaviors. However, a great difference was observed in the fracture mechanism for the blend with PCL of lower molar mass, which did not present the ability to fibrillate before rupture, due to its low mechanical resistance. The blends showed greater water uptake capabilities when compared to the pure polymers due to the diffusion of water through the gaps in between the phases. The blends showed high cell viability when tested in fibroblast cells of the L929 lineage and pre‐osteoblast cells of the MCT3‐E1 lineage, indicating that these materials are promising for application in bone tissue engineering.

Shape memory thermoplastic polyurethane/polycaprolactone blend and composite with hydroxyapatite for biomedical application

Depending on its composition, thermoplastic polyurethane (TPU)/polycaprolactone (PCL) blend may present interesting properties for biomedical applications. Here, we have extensively developed and characterized blends of TPU/PCL and composites with 5, 10, and 20 wt% of hydroxyapatite (HA). The thermal, rheological, and mechanical characterizations showed that the blends present an intermediate behavior between pure TPU and PCL. The 75TPU/25PCL blend exhibited the best shape memory performance at temperatures below 50 °C. Filaments of this blend presented a fixation rate of 86.6% and a recovery rate of 73.3% at 50 ℃. The addition of HA had little influence on the shape memory properties; on the other hand, it strengthened the material, reaching elastic modulus values close to 100 MPa. In vitro tests revealed a biocompatible behavior for all blends, and the composite with 10 wt% HA from the 75TPU/25PCL blend demonstrated greater cell proliferation compared to the other composites.Graphical abstract

Preparation and Characterization of Poliglecaprone-Incorporated Polycaprolactone Composite Fibrous Scaffolds

Electrospun fibrous scaffolds made from polymers such as polycaprolactone (PCL) have been used in drug delivery and tissue engineering for their viscoelasticity, biocompatibility, biodegradability, and tunability. Hydrophobicity and the prolonged degradation of PCL causes inhibition of the natural tissue-remodeling processes. Poliglecaprone (PGC), which consists of PCL and Poly (glycolic acid) (PGA), has better mechanical properties and a shorter degradation time compared to PCL. A blend between PCL and PGC called PPG can give enhanced shared properties for biomedical applications. In this study, we fabricated a blend of PCL and PGC nanofibrous scaffold (PPG) at different ratios of PGC utilizing electrospinning. We studied the physicochemical and biological properties, such as morphology, crystallinity, surface wettability, degradation, surface functionalization, and cellular compatibility. All PPG scaffolds exhibited good uniformity in fiber morphology and improved mechanical properties. The surface wettability and degradation studies confirmed that increasing PGC in the PPG composites increased hydrophilicity and scaffold degradation respectively. Cell viability and cytotoxicity results showed that the scaffold with PGC was more viable and less toxic than the PCL-only scaffolds. PPG fibers were successfully coated with polydopamine (PDA) and collagen to improve degradation, biocompatibility, and bioactivity. The nanofibrous scaffolds synthesized in this study can be utilized for tissue engineering applications such as for regeneration of human articular cartilage regeneration and soft bones.