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The protein from black soldier fly larvae was used as a functional ingredient of a novel green nanofiber. Larvae protein powder (LP) was blended with biodegradable poly(ε-caprolactone) (PCL) and processed in an electrospinning machine using a coaxial feeding/mixing method to produce nanofibers approximately 100–350 nm in diameter. To improve the dispersion and interface bonding of various PCL/LP nanofiber components, a homemade compatibilizer, maleic anhydridegrafted poly(ε-caprolactone) (MPCL), was added to form MPCL/LP nanofibers. The structure, morphology, mechanical properties, water absorption, cytocompatibility, wound healing, and biodegradability of PCL/LP and MPCL/LP nanofiber mats were investigated. The results showed enhanced adhesion in the MPCL/LP nanofiber mats compared to PCL/LP nanofiber mats; additionally, the MPCL/LP nanofibers exhibited increases of approximately 0.7–2.2 MPa in breaking strength and 9.0–22.8 MPa in Young’s modulus. Decomposition tests using a simulated body fluid revealed that the addition of LP enhanced the decomposition rate of both PCL/LP and MPCL/LP nanofiber mats and in vitro protein release. Cell proliferation and migration analysis indicated that PCL, MPCL, and their composites were biocompatible for fibroblast (FB) growth. Biodegradability was tested in a 30 day soil test. When the LP content was 20 wt%, the degradation rate exceeded 50%.

Amphiphilic block copolymers, made of biocompatible polycaprolactone (PCL) and polyethylene glycol (PEG), due to their ability to self‐assemble in water into nanoscopic micelles, have been largely exploited for drug delivery systems (DDS). This study introduces a novel approach by synthesizing a fluorescein isothiocyanate FITC‐labelled PCL‐PEG‐PCL triblock copolymer, with the aim to develop a drug delivery system for natural bioactive. As a proof of concept, the FITC‐labelled PCL‐PEG‐PCL copolymer is applied for the preparation of micelles encapsulating into the core capsaicin (CP), a pungent alkaloid found in chili peppers with diverse therapeutic applications. Challenges associated with CP′s solubility, bioavailability, and stability are addressed using this DDS. Comprehensive characterization of FITC‐labelled copolymer is conducted using a range of analytical techniques, including nuclear magnetic resonance (NMR), dynamic light scattering (DLS), high‐performance liquid chromatography (HPLC), Fourier‐transform infrared spectroscopy (FTIR), fluorescence, and confocal laser scanning microscopy (CLSM). Key properties such as critical micelle concentration, CP loading, and release behavior are thoroughly investigated and compared with the characteristics of the unlabeled parent copolymer. This research pioneers the investigation of PCL‐PEG‐PCL triblock copolymers for CP delivery, along with the use of FITC‐labelled variants, opening new avenues for research in drug delivery and nanomedicine. [ABSTRACT FROM AUTHOR]

In this study, we investigated the influence of γ-irradiation (0, 50, and 100 kGy) doses on the chemical and mechanical properties of biodegradable poly(hydroxybutyrate-valerate)/poly(caprolactone) (PHBV/PCL) polymer blends rich in low-molar-mass PCL, which were prepared using a co-rotating twin-screw extruder. In parallel, the density functional theory (DFT) and the time-dependent DFT (TD-DFT) methods were used together with a model containing four monomer units to provide an insight into the electronic structure, chemical bonds, and spectroscopic (such as Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis)) properties of PHBV and PCL blend phases, which are critical for predicting and designing new materials with desired properties. We found that an increase in γ-irradiation doses caused splitting instead of crosslinks in the polymer chains, which led to evident deformation and an increase in tensile strength at break of 2.0 to 5.7 MPa for the PHBV/PCL blend. Further, this led to a decrease in crystallinity and proved the occurrence of a more favorable interaction between the blend phases.

The elaboration of potent delivery systems for peptides/proteins is still a challenge but is increasingly needed in advanced therapy. In the present research, we have developed a nanoencapsulation system for peptides/proteins, which is suitable for the delivery of hydrophilic bioactive compounds. The preparation method combines the advantageous properties of reverse nanoemulsion and nanoprecipitation, resulting in the formation of nanoparticles in the size range of 350–500 nm. The polymeric coating composed of polycaprolactone allows chemical functionalization and protection while the inner microenvironment (containing 1-decanoyl-rac-glycerol and N,N-dimethyldodecylamine N-oxide surfactants) provides aqueous surrounding for the active with structural fidelity. Hen egg white lysozyme and β-lactoglobulin were successfully encapsulated, achieving protein contents of 10–60 μg/mg and encapsulation efficiencies ranging from 5–50% depending on the protein type and loading concentration. In vitro release measurement showed a biphasic sustained release profile of both proteins in the time range of one month. In vitro cytotoxicity investigation of protein-loaded nanoparticles exhibited good cell viability (above 95% at the highest treatment concentration of 0.3 mg/ml). The encapsulated membrane-active peptides have shown improved bioactivity.

A simple and efficient method for the synthesis of biodegradable, highly branched polycaprolactone (PCL) is presented. The solvent-free (bulk) reaction was carried out via ring opening polymerization (ROP), catalyzed by tin octanoate Sn(Oct)2, and it employed hyperbranched polyamide (HPPA) as a macro-initiator. The core–shell structure of the obtained products (PCL-HPPA), with the hyperbranched HPPA core and linear PCL chains as shell, was in the focus of the product characterization. 1H nuclear magnetic resonance (1H NMR) and elemental analysis confirmed the covalent incorporation of the HPPA in the products, as well as a high degree of grafting conversion of its amino functional groups. Confocal Raman Micro spectroscopy, and especially Time-of-Flight Secondary Ion Mass Spectrometry, further supported the existence of a core–shell structure in the products. Direct observation of macromolecules by means of cryogenic transmission electron microscopy, as well as gel permeation chromatography (GPC), suggested the existence of a minor 'aggregated' product fraction with multiple HPPA cores, which was attributed to transesterification reactions. Differential scanning calorimetry, as well as X-ray diffraction, demonstrated that the PCL-HPPA polymers displayed a similar degree of crystallinity to linear neat PCL, but that the branched products possessed smaller and less regular crystallites. [ABSTRACT FROM AUTHOR]

In this study, we investigated the influence of γ-irradiation (0, 50, and 100 kGy) doses on the chemical and mechanical properties of biodegradable poly(hydroxybutyrate-valerate)/poly(caprolactone) (PHBV/PCL) polymer blends rich in low-molar-mass PCL, which were prepared using a co-rotating twin-screw extruder. In parallel, the density functional theory (DFT) and the time-dependent DFT (TD-DFT) methods were used together with a model containing four monomer units to provide an insight into the electronic structure, chemical bonds, and spectroscopic (such as Nuclear Magnetic Resonance (NMR) and Ultraviolet-visible (UV-vis)) properties of PHBV and PCL blend phases, which are critical for predicting and designing new materials with desired properties. We found that an increase in γ-irradiation doses caused splitting instead of crosslinks in the polymer chains, which led to evident deformation and an increase in tensile strength at break of 2.0 to 5.7 MPa for the PHBV/PCL blend. Further, this led to a decrease in crystallinity and proved the occurrence of a more favorable interaction between the blend phases. [ABSTRACT FROM AUTHOR]

In recent years, solid polymer electrolytes (SPE) has attracted much attention because of its good safety and environmental stability, among which poly(ε-caprolactone) (PCL) based solid electrolyte film is one of the most potential materials. We have adopted the method of synthesizing polymer nanocomposites with natural clay, which can effectively meet the needs of electrolytes. In this study, cetyl trimethyl ammonium bromide (CTAB) was used to modify rectorite (REC), and the ε-CL monomer is inserted between the rectorite silicate layers. PCL/organic rectorite (OREC) nanocomposites were synthesized by in situ intercalation polymerization. The yield of the polymer nanocomposite could reach 93.6% when the molecular weight of the polymer nanocomposite was 39 000. The effects of OREC addition on the morphology, thermal stability, and electrochemical properties of PCL/OREC nanocomposites were investigated by various characterization methods. The temperature can be increased by 50 °C when the thermal decomposition is 50 wt%, and the crystallinity decreases by 4.6%. Composite polymerelectrolytes (CPEs) (PCL/OREC) showed a good electrical conductivity of 1.13·10–4 S·cm–1 at 60 °C and an excellent capacity retention rate of 96.7% after 100 cycles at 0.5 C current density. This study has important guiding significance for the development of polymer nanocomposites as solid electrolytes.

Abstract Larval therapy has been reported to be beneficial in the treatment of chronic wounds by promoting granulation tissue formation, due to its antimicrobial properties and by degrading necrotic tissue. However, the use of live maggots is problematic for patient acceptance, and thus there is a need to develop materials which can release therapeutic biomolecules derived from maggot secretions to the wound bed. Here we describe the fabrication of a novel bioactive scaffold that can be loaded with Lucilia sericata maggot alimentary excretion/secretion fluids (L. sericata maggot E/S), and which can also provide structural stability for mammalian cell-growth and migration to support wound repair. Electrospun scaffolds were prepared from a poly(caprolactone)-poly(ethylene glycol)–block copolymer (PCL-b-PEG) blended with PCL with average fibre diameters of ~ 4 μm. The scaffolds were hydrophilic and were able to support viable fibroblasts that were able to infiltrate throughout the extent of the scaffold thickness. L. sericata maggot (E/S) was subsequently adsorbed to the surface and released over 21 days with retention of the protease activity that is responsible for supporting fibroblast migration. The incorporation of L. sericata maggot E/S on the surface of the electrospun fibres of PCL-PEG/PCL fibres is a novel approach with potential for future application to support skin wound healing within a clinical setting.

A simple and efficient method for the synthesis of biodegradable, highly branched polycaprolactone (PCL) is presented. The solvent-free (bulk) reaction was carried out via ring opening polymerization (ROP), catalyzed by tin octanoate Sn(Oct)2, and it employed hyperbranched polyamide (HPPA) as a macro-initiator. The core–shell structure of the obtained products (PCL-HPPA), with the hyperbranched HPPA core and linear PCL chains as shell, was in the focus of the product characterization. 1H nuclear magnetic resonance (1H NMR) and elemental analysis confirmed the covalent incorporation of the HPPA in the products, as well as a high degree of grafting conversion of its amino functional groups. Confocal Raman Micro spectroscopy, and especially Time-of-Flight Secondary Ion Mass Spectrometry, further supported the existence of a core–shell structure in the products. Direct observation of macromolecules by means of cryogenic transmission electron microscopy, as well as gel permeation chromatography (GPC), suggested the existence of a minor ‘aggregated’ product fraction with multiple HPPA cores, which was attributed to transesterification reactions. Differential scanning calorimetry, as well as X-ray diffraction, demonstrated that the PCL-HPPA polymers displayed a similar degree of crystallinity to linear neat PCL, but that the branched products possessed smaller and less regular crystallites.

The development of new materials is currently focused on replacing fossil-based plastics with sustainable materials. Obtaining new bioplastics that are biodegradable and of the greenest possible origin could be a great alternative for the future. However, there are some limitations—such as price, physical properties, and mechanical properties—of these bioplastics. In this sense, the present work aims to explore the potential of lignin present in black liquor from paper pulp production as the main component of a new plastic matrix. For this purpose, we have studied the simple recovery of this lignin using acid precipitation, its thermoplastification with glycerin as a plasticizing agent, the production of blends with poly(caprolactone) (PCL), and finally the development of biocomposite materials reinforcing the blend of thermoplastic lignin and PCL with stone groundwood fibers (SGW). The results obtained show that thermoplastic lignin alone cannot be used as a bioplastic. However, its combination with PCL provided a tensile strength of, e.g., 5.24 MPa in the case of a 50 wt.% blend. In addition, when studying the properties of the composite materials, it was found that the tensile strength of a blend with 20 wt.% PCL increased from 1.7 to 11.2 MPa with 40 wt.% SGW. Finally, it was proven that through these biocomposites it is possible to obtain a correct fiber–blend interface. [ABSTRACT FROM AUTHOR]

Preparation of a di-block copolymer was investigated by changing the synthetic condition and utilization of 2-isopropyl-2-oxazoline (PiPrOx) as a hydrophilic part and polycaprolactone (PCL) as a hydrophobic segment via ring-opening polymerization (ROP). The copolymer chains were functionalized with hydrazine to be chemically bonded to doxorubicin (DOX, as a hydrophobic drug model) and generating pH-sensitive moiety for the copolymer. The cystamine was crafted as the glutathione-responsiveness counterpart and the poly(2-isopropyl-2-oxazoline) linkage plays a thermal sensitivity role. According to the worthwhile findings of the research, the synthesized nanomicelle can be suggested as a potential candidate for controlled fashion drug delivery systems. Illustration of self-assembly and drug entrapment of the triple-stimuli block copolymer for sustained DOX-delivery [ABSTRACT FROM AUTHOR]

The two‐way shape memory effect is the ability of a material to change its shape between two configurations upon application and removal of a stimulus, and, among shape memory polymers, it is featured only by few systems, such as semicrystalline networks. When studied under tensile conditions, it consists of elongation–contraction cycles along cooling and heating across the crystallization and melting region, typically under the application of a constant load. However, recent studies on crosslinked semicrystalline co‐polymers demonstrate that also a completely stress‐free, or self‐sustained, two‐way effect may be achieved through specific thermomechanical cycles. This effect is currently regarded with interest for the development of intrinsically reversible sensors and actuators, and it may also be displayed by simpler materials, as homopolymer‐based semicrystalline networks. Only seldom articles investigate this possibility, therefore in this work the two‐way shape memory behavior is studied on a poly(ɛ‐caprolactone) system, crosslinked by means of a sol‐gel approach. The effect is studied both under stress‐driven and stress‐free condition, by applying properly set‐up thermo‐mechanical histories. The results allow to describe the effect as a function of temperature, to reveal the dependence on specific testing parameters and to compare the extent of the reversible strain variation under these two conditions. [ABSTRACT FROM AUTHOR]

Biomaterial-based approaches for bone regeneration seek to explore alternative strategies to repair non-healing fractures and critical-sized bone defects. Fracture non-union occurs due to a number of factors resulting in the formation of bone defects. Rigorous evaluation of the biomaterials in relevant models and assessment of their potential to translate towards clinical use is vital. Large animal experimentation can be used to model fracture non-union while scaling-up materials for clinical use. Growth factors modulate cell phenotype, behaviour and initiate signalling pathways leading to changes in matrix deposition and tissue formation. Bone morphogenetic protein-2 (BMP-2) is a potent osteogenic growth factor, with a rapid clearance time in vivo necessitating clinical use at a high dose, with potential deleterious side-effects. The current studies have examined the potential for Laponite® nanoclay coated poly(caprolactone) trimethacrylate (PCL-TMA900) scaffolds to bind BMP-2 for enhanced osteoinduction in a large animal critical-sized bone defect. An ovine femoral condyle defect model confirmed PCL-TMA900 scaffolds coated with Laponite®/BMP-2 produced significant bone formation compared to the uncoated PCL-TMA 900 scaffold in vivo, assessed by micro-computed tomography (μCT) and histology. This indicated the ability of Laponite® to deliver the bioactive BMP-2 on the PCL-TMA900 scaffold. Bone formed around the Laponite®/BMP-2 coated PCL-TMA900 scaffold, with no erroneous bone formation observed away from the scaffold material confirming localisation of BMP-2 delivery. The current studies demonstrate the ability of a nanoclay to localise and deliver bioactive BMP-2 within a tailored octet-truss scaffold for efficacious bone defect repair in a large animal model with significant implications for translation to the clinic., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Prof Richard Oreffo reports financial support was provided by Biotechnology and Biological Sciences Research Council. Prof Molly Stevens reports financial support was provided by UK Regenerative Medicine Platform, and she invested in, consults for (or is on the scientific advisory boards or boards of directors) and conducts sponsored research funded by companies related to the biomaterials field. R.O.C. Oreffo and J.I. Dawson are co-founders and shareholders in a university spin out company with a license to IP indirectly related to the current manuscript. All other authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

In vitro models of pathological cardiac tissue have attracted interest as predictive platforms for preclinical validation of therapies. However, models reproducing specific pathological features, such as cardiac fibrosis size (i.e., thickness and width) and stage of development are missing. This research was aimed at engineering 2D and 3D models of early-stage post-infarct fibrotic tissue (i.e., characterized by non-aligned tissue organization) on bioartificial scaffolds with biomimetic composition, design, and surface stiffness. 2D scaffolds with random nanofibrous structure and 3D scaffolds with 150 µm square-meshed architecture were fabricated from polycaprolactone, surface-grafted with gelatin by mussel-inspired approach and coated with cardiac extracellular matrix (ECM) by 3 weeks culture of human cardiac fibroblasts. Scaffold physicochemical properties were thoroughly investigated. AFM analysis of scaffolds in wet state, before cell culture, confirmed their close surface stiffness to human cardiac fibrotic tissue. Following 3 weeks culture, biomimetic biophysical and biochemical scaffold properties triggered the activation of myofibroblast phenotype. Upon decellularization, immunostaining, SEM and two-photon excitation fluorescence microscopy showed homogeneous decoration of both 2D and 3D scaffolds with cardiac ECM. The versatility of the approach was demonstrated by culturing ventricular or atrial cardiac fibroblasts on scaffolds, thus suggesting the possibility to use the same scaffold platforms to model both ventricular and atrial cardiac fibrosis. In the future, herein developed in vitro models of cardiac fibrotic tissue, reproducing specific pathological features, will be exploited for a fine preclinical tuning of therapies.

In this work, the copolymers ethylene-glycidyl methacrylate (E-GMA), ethylene methyl methacrylate-glycidyl methacrylate (EMA-GMA), and styrene-(ethylene-butylene)-styrene grafted with maleic anhydride (SEBS-g-MA) were used to compatibilize polystyrene (PS)/poly(caprolactone) (PCL) blends. The blends were processed in a co-rotating twin-screw extruder and injection molded. Samples were investigated by torque rheometry, capillary rheometry, impact strength, tensile strength, heat deflection temperature (HDT), dynamic-mechanical thermal analysis (DMTA), thermogravimetry (TG), and scanning electron microscopy (SEM). Torque rheometry indicated that glycidyl methacrylate functional groups and maleic anhydride groups interact with PCL. Capillary rheometry evidenced that at shear rates lower than 10,000 s−1, the PS/PCL/SEBS-g-MA blends presented the highest apparent viscosity among the blends. Such behavior was possibly due to the good interaction between SEBS-g-MA and the PS and PCL phases. Consequently, the properties of impact strength, elongation at break, tensile strength, and elastic modulus were improved by 30%, 109%, 33.8%, and 13.7%, respectively, compared with the non-compatibilized PS/PCL system. There was a reduction in the HDT of all blends compared with neat PS, given the elastomeric characteristics of PCL and compatibilizers. The DMTA results revealed two independent peaks in the blends (one around −53 °C concerning the PCL phase and another at 107 °C related to PS), confirming their immiscibility. The PS/PCL/SEBS-g-MA blends showed higher morphological stability, confirming their good mechanical properties. [ABSTRACT FROM AUTHOR]

In the present study, neonate keratinocytes were cocultured with human adipose-derived mesenchymal stem cells (hAMSCs) on the electrospun polycaprolactone-platelet gel (PCL–PG) scaffold. To evaluate its potential of wound healing and skin tissue engineering, neonate keratinocytes must be differentiated. The PCL scaffold prepared by the electrospinning technique was fabricated and coated by PG. Then scaffolds were fully characterized by SEM, contact angle, FTIR–ATR, and tensile test. Following seeding hAMSCs as a feeder layer, neonate keratinocytes were cocultured directly on PCL–PG scaffolds and neat PCL. The hAMSCs and neonate keratinocytes' viability was measured using MTT assay for up to 10 days (1st, 3rd, 5th, 7th, and 10th days). To examine the epidermal maturation, cytokeratin 10 and loricrin determinants detection was used through immunocytochemistry (ICC). In addition, real-time PCR was used to examine keratinocyte marker genes in keratin 10, keratin 14, and Involucrin. The MTT assay results showed higher cell viability and the proliferation of neo-keratinocytes on PCL–PG fibrillar scaffolds than the PCL scaffold. On the PCL–PG scaffolds in the presence of hAMSCs as a feeder layer, the PCR and ICC analysis had a higher cell differentiation compared to neat PCL scaffolds. Moreover, SEM images showed that the keratinocytes cocultured with hAMSCs demonstrated a better proliferation and adhesion on PCL–PG nanofiber scaffolds. Based on results, PG increased the nanofibrous PCL scaffold's biological properties, including hydrophilicity, cell attachment, cell viability, and expression of keratinocyte markers in the neat keratinocytes and hAMSCs coculture system. The findings support the potential of this engineered construct for engineering skin tissue and wound dressing. [ABSTRACT FROM AUTHOR]

This study evaluated the potential of using poly(lactic acid)/poly(ε-caprolactone) (PLA/PCL) blends for fused filament fabrication (FFF) and assembly with pure PLA for biomedical applications. PLA/PCL binary blends were meltblended in a twin-screw extruder at different ratios (20/80 to 80/20) and then formed into filaments with a calibrated diameter for FFF. The microstructure, surface properties, and rheological and mechanical behaviors of the blends were assessed. The blends were immiscible but showed signs of adhesion between the phases. It was determined that the fibrillar morphology of inclusions for PLA/PCL ratios higher than 30/70 proved to be driven by the manufacturing process. The tensile mechanical behaviors of printed and injected samples were similar, and their Young’s modulus was simulated using Halpin-Tsai and Mori Tanaka models based on the sample microstructure. The ductility of the blends was strongly driven by the behavior of its majority phase. Finally, specific samples were designed to characterize the tensile strength between PLA and its blends by entangling layers of both materials. The strength of the assembly was found to be dependent on the phase that was continuous and was governed by the strength and the viscosity of the blend.

Insulin-like growth factor-1 receptor (IGF-1R) is expressed in malignant and normal breast tissue, and its intermittent activation by multiple IGF-1 signaling pathways leads to neoplasm cell proliferation, impaired apoptosis, increased survival, and resistance to cytotoxic therapeutic agents. Therefore, simultaneous suppression of the receptor and its cognate ligand would be a powerful promising strategy inhibiting malignant phenotypes of breast cancer cells. In the present study, Methoxypoly(ethylene glycol) - Poly(caprolactone) was hybridized with Dimethyldioctadecylammonium bromide (DDAB) cationic lipid (mPEG-PCL-DDAB) nanoparticles (NPs) and used as a carrier for simultaneous delivery of lycopene and insulin-like growth factor 1 receptor-specific lycopene encapsulated-mPEG-PCL-DDAB nanoparticle/siRNA to MCF-7 breast cancer cells. Then, the antitumor effects of this construct were evaluated in vitro. The results demonstrated that the synthesized mPEG-PCL-DDAB nanoparticle had suitable physicochemical properties. The use of mPEG-PCL-DDAB nanoparticle-loaded anti-insulin-like growth factor 1 receptor-siRNA and lycopene dramatically induced the process of apoptosis and arrested cell cycle in the MCF-7 tumor cell lines. In general, the findings of this study demonstrated the potency of mPEG-PCL-DDAB nanoparticles for dual delivery of siRNA, and lycopene in breast cancer cell lines followed the induction of apoptosis. [ABSTRACT FROM AUTHOR]

Herein, a straightforward approach is reported to obtain photo‐crosslinked, bioresorbable poly(ε‐caprolactone) (PCL) based networks covering a range of mechanical properties (elongation at break from 203 ± 53 up to 707 ± 101% and ultimate strength from 6.8 ± 2.2 to 13.9 ± 1.5 MPa) via alteration of the network topology. Exploiting multifunctional thiols for crosslinking of acrylate‐terminated PCL is an effective method to alter the mechanical properties of photo‐crosslinked networks due to the chain transferring ability of the thiols. By controlling the thiol to acrylate ratio, the Young's modulus, elongation at break and ultimate strength can be significantly altered. The materials described in this work can be considered potential candidates for light‐based 3D‐printing and to serve tissue engineering applications. [ABSTRACT FROM AUTHOR]

As a novel transdermal delivery system, core–shell nanofibers exhibit a more controlled drug release than mono-structure nanofibers, especially when the hydrophilicity of core and shell polymers is different. Thus, this study aimed to produce biocompatible and antimicrobial erythromycin-loaded poly(caprolactone) (PCL/erythromycin) core with a zein-containing titanium dioxide (zein/TiO2) shell nanofibers. Accordingly, a specified concentration of PCL solution containing erythromycin and zein solution with titanium dioxide nanoparticle was prepared. Then, core–shell nanofibers were fabricated using co-axial electrospinning equipped with nozzles with different inner and outer diameters. The obtained morphology and diameter of core–shell nanofibers were characterized by scanning electron microscope (SEM) and were compared with the SEM images of PCL nanofibers, PCL/erythromycin nanofibers, zein nanofibers, zein/TiO2 nanofibers and PCL@zein core–shell nanofibers. The SEM images of PCL/erythromycin@zein/TiO2 nanofibers show that core–shell nanofibers are clearly fine, narrow, uniform and smooth without any adhesion with an average diameter of 625 nm. The core–shell structure of PCL@zein and PCL/erythromycin@zein/TiO2 nanofibers were confirmed by transmission electron microscope. The structure of nanofibers was approved by Fourier transform infrared and X-ray diffraction, showing the presence of PCL, zein, erythromycin and titanium dioxide in the obtained nanofibers. Moreover, UV–Vis spectroscopy was used to determine the in vitro drug release profile of erythromycin from prepared core–shell nanofibers, indicating the slow-release profile of the drug in 72 h. The antimicrobial properties of the core–shell nanofibers were considered by the zone of inhibition against Staphylococcus aureus, Bacillus cereus, Escherichia coli and Salmonella bacteria. The results showed that core–shell nanofibrous mats possess excellent antimicrobial activities. [ABSTRACT FROM AUTHOR]

The aim of this study was to prepare triamcinolone acetonide (TA)-loaded poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) and poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) micelles as a potential treatment of ocular inflammation. The micelles were evaluated for particle size, drug loading capacity and drug release kinetics. Selected micellar formulations were dispersed into chitosan hydrogel and their anti-inflammatory properties were tested in rabbits using a carrageenan-induced ocular inflammatory model. Particle size ranged from 59.44 ± 0.15 to 64.26 ± 0.55 nm for PEG-b-PCL and from 136.10 ± 1.57 to 176.80 ± 2.25 nm for PEG-b-PLA micelles, respectively. The drug loading capacity was in the range of 6–12% and 15–25% for PEG-b-PCL and PEG-b-PLA micelles, respectively and was dependent on the drug/polymer weight ratio. TA aqueous solubility was increased by 5- and 10-fold after loading into PEG-b-PCL and PEG-b-PLA micelles at a polymer concentration as low as 0.5 mg/mL, respectively. PEG-b-PLA micelles suspended in chitosan hydrogel were able to sustain the drug release where only 42.8 ± 1.6% drug was released in one week. TA/PEG-b-PLA micelles suspended in chitosan hydrogel had better anti-inflammatory effects compared with the plain drug hydrogel or the drug micellar solution. Complete disappearance of the corneal inflammatory changes was observed for the micellar hydrogel. These results confirm the potential of PEG-b-PLA micelles suspended in chitosan hydrogel to enhance the anti-inflammatory properties of triamcinolone acetonide.

Spiral-vane electrospinning (SVE), a novel needleless electrospinning, was proven effective in obtaining high-throughput production of nanofibers. However, the properties of the electrospun nanofibers produced by SVE remain relatively underexplored, especially in comparison with those made by traditional single-needle electrospinning (SNE). Hence, for the comparative study of SNE and SVE in this study, the difference in the preparation mechanism was first analyzed using numerical simulation, followed by the experimental analysis of the effects of spinneret types on the quality and biocompatibility of electrospun poly(caprolactone)/gelatin (PCL/Gel) nanofibers. The values predicted by the electric field results were consistent with the experimental data, showing that the PCL/Gel nanofibers prepared by SVE have higher yields than SNE. Although the different spinnerets (i.e., needle and spiral vane) had little effect on the surface chemistry, thermal stability, and composition of the PCL/Gel nanofibers, they had great effects on the fiber diameter distribution and mechanical properties in which SVE-electrospun nanofibers have the wider diameter distribution and higher softness. Furthermore, the SVE-electrospun nanofibers were also proven to exhibit good biocompatibility for cell growth of human adipose-derived stem cells (hADSCs) and cell–fiber interactions. Summarily, compared to the traditional SNE, SVE-electrospun nanofibers exhibited many merits including high-throughput yield, good air permeability, and compliance, which provide a facile and effective platform for the improvement of nanofiber applications in biomedical fields (e.g., tissue engineering, cosmetic, and medical textiles).

editorial

The distinct structural properties and osteogenic capacity are important aspects to be taken into account when developing guided bone regeneration membranes. Herein, inspired by the structure and function of natural periosteum, we designed and fabricated using electrospinning a fibrous membrane comprising (poly)--ε-caprolactone (PCL), collagen-I (Col) and mineralized Col (MC). The three-layer membranes, having PCL as the outer layer, PCL/Col as the middle layer and PCL/Col/MC in different ratios (5/2.5/2.5 (PCM-1); 3.3/3.3/3.3 (PCM-2); 4/4/4 (PCM-3) (%, w/w/w)) as the inner layer, were produced. The physiochemical properties of the different layers were investigated and a good integration between the layers was observed. The three-layered membranes showed tensile properties in the range of those of natural periosteum. Moreover, the membranes exhibited excellent water absorption capability without changes of the thickness. In vitro experiments showed that the inner layer of the membranes supported attachment, proliferation, ingrowth and osteogenic differentiation of human bone marrow-derived stromal cells. In particular cells cultured on PCM-2 exhibited a significantly higher expression of osteogenesis-related proteins. The three-layered membranes successfully supported new bone formation inside a critical-size cranial defect in rats, with PCM-3 being the most efficient. The membranes developed here are promising candidates for guided bone regeneration applications. [ABSTRACT FROM AUTHOR]

Extrusion‐based 3D printing of polymeric biomaterials has emerged as a promising approach for the fabrication of complex tissue engineering constructs. However, the large pore and feature size lead to low cell seeding efficiency and limited control of spatial distribution of cells within the scaffolds. We developed hybrid scaffolds that are composed of 3D‐printed layers and airbrushed fibrous membranes. Airbrushing time was adjusted to fabricate low (L), medium (M), and high (H) density membranes to effectively control stem cell infiltration. When two distinct populations of stem cells were seeded from top or bottom of the scaffolds, scaffolds composed of LLL membranes showed gradual mixing of the cells with depth, whereas LHL membranes led to two distinct regions of cells separated by the H membrane. Our results demonstrate that fibrous membranes incorporated within 3D‐printed layers enable user‐defined and spatially controlled cell compositions within hybrid scaffolds. [ABSTRACT FROM AUTHOR]

This paper investigates the effectiveness of a viscosity ratio model to predict phase inversion in poly(lactic acid)/poly(caprolactone) (PLA/PCL) blends. From capillary rheometry measurements, the melt viscosities of PLA and PCL were found to be 1298 and 1758 Pas respectively, at the temperature and shear strain rate of the melt blending process. Using these values, phase inversion was predicted to occur at 54 wt% of PCL. This prediction was validated both by optical microscopy and also by scanning electron microscopy (SEM) in which one of the phases had been removed by etching. For mechanical properties, the co-continuous phase morphology gave good ductility with balanced modulus and yield stress. Contact angle measurements were used to evaluate the surface energies of PLA and PCL. Experimental results of 35.5 and 44.0 mNm−1, respectively, agreed well with the values of 37.6 and 46.0 mNm−1 calculated from the Parachor method. Biodegradation tests in compost and degradation tests in phosphate buffer solution revealed that PLA and PCL hydrolyze by different mechanisms. PLA undergoes bulk degradation and brittle failure occurs after an incubation time, whereas PCL undergoes surface degradation. Prediction of phase inversion allows control of the morphology and hence the biodegradation and hydrolytic degradation behavior. [ABSTRACT FROM AUTHOR]

Molecularly imprinted polymers (MIP) are materials capable of recognizing specific molecules, usually through non-covalent bonds. In this work, gallic acid (GA) was selected as the imprinting molecule, and MIP for GA (MIP-GA) was synthesized by bulk polymerization. X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) confirmed the MIP-GA recognition property. Poly(caprolactone) mat containing MIP-GA particles (MIM-GA) was produced by electrospinning, which was morphologically characterized by Scanning electron microscopy (SEM). Functionalized MIM-GA was obtained by washes sequence in methanol for the GA removal from MIM-GA. The GA removal was confirmed by High-performance liquid chromatography (HPLC) with UV-Vis detection at 214 and 268 nm. The functionalized MIM-GA immersed in GA methanolic solution with a concentration of 1.0 mM extracted 96±1.5% of GA at t = 150 minutes. The vibrational modes obtained from FT-IR spectra confirmed the chemical composition of MIM-GA and its functionalization through of band at 770 cm-1. The contact angle measurements were 134.0±1.0° for electrospun MIM-GA and 125.0±1.2° for functionalized MIM-GA. The decrease was due to the absence of GA after the functionalization process. The produced MIM-GA by electrospinning acquired the recognition property of the GA imprinted polymer synthesized, which can be used for the specific detection, extraction, and purification of this important natural polyphenol. [ABSTRACT FROM AUTHOR]

In this study, polycaprolactone/chitosan/1% baghdadite composite coating was applied on anodized AZ91 alloy to improve the corrosion rate of AZ91 alloy in simulated body fluid (SBF) solution for long immersion times, control its degradability and enhance its bioactivity. By applying the composite coating and after seven days of immersion in a phosphate buffer solution, the corrosion rate decreased from 0.21 mg/h.cm2 (for AZ91 sample) to 0.1 mg/h.cm2 (for anodized AZ91 sample). Formation of apatite layer on the surface of specimens is considered a criterion for bioactivity. In order to evaluate the ability of specimens to get covered by an apatite, the SBF test was used. Application of the composite coating yielded the highest ability for apatite formation, controlled release of ions, and the lowest corrosion rate in the SBF so that it could be considered a good choice for bone implants.

This work provides a convenient low‐cost strategy for fast fabrication of dansyl‐based fluorescent nanofibers for development of latent fingerprints aiming forensic applications. Polycaprolactone (PCL) and dansyl cadaverine (DnsCad) or dansylglycine (DnsGly) nanofibers are prepared by electrospinning technique and characterized by SEM, FTIR, thermal analysis, and fluorescence spectroscopy. The electrospun PCL/DnsCad and PCL/DnsGly nanofibers are fluorescent with greenish blue and yellowish green emission, respectively. Such nanofibers are useful for enhancement of the visual contrast of latent fingerprints on metallic surfaces when exposed to UV light. These findings are particularly important for development of latent fingerprints on cartridge cases. [ABSTRACT FROM AUTHOR]

The aim of this study was to prepare triamcinolone acetonide (TA)-loaded poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) and poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) micelles as a potential treatment of ocular inflammation. The micelles were evaluated for particle size, drug loading capacity and drug release kinetics. Selected micellar formulations were dispersed into chitosan hydrogel and their anti-inflammatory properties were tested in rabbits using a carrageenan-induced ocular inflammatory model. Particle size ranged from 59.44 ± 0.15 to 64.26 ± 0.55 nm for PEG-b-PCL and from 136.10 ± 1.57 to 176.80 ± 2.25 nm for PEG-b-PLA micelles, respectively. The drug loading capacity was in the range of 6–12% and 15–25% for PEG-b-PCL and PEG-b-PLA micelles, respectively and was dependent on the drug/polymer weight ratio. TA aqueous solubility was increased by 5- and 10-fold after loading into PEG-b-PCL and PEG-b-PLA micelles at a polymer concentration as low as 0.5 mg/mL, respectively. PEG-b-PLA micelles suspended in chitosan hydrogel were able to sustain the drug release where only 42.8 ± 1.6% drug was released in one week. TA/PEG-b-PLA micelles suspended in chitosan hydrogel had better anti-inflammatory effects compared with the plain drug hydrogel or the drug micellar solution. Complete disappearance of the corneal inflammatory changes was observed for the micellar hydrogel. These results confirm the potential of PEG-b-PLA micelles suspended in chitosan hydrogel to enhance the anti-inflammatory properties of triamcinolone acetonide. [ABSTRACT FROM AUTHOR]

Focal therapies such as hyperthermia have been successfully used to treat solid localized tumors; however, they are not easily applied to cancers that may present in a disseminated form such as ovarian cancer. To address this need, iron oxide (IO) particles were incorporated into microporous poly(caprolactone) scaffolds previously shown to recruit disseminating cancer cells. Under an alternating magnetic field, IO‐loaded scaffolds exhibited heating and killed ID8 ovarian cancer cells in vitro. After implantation in the intraperitoneal cavity of mice, IO‐loaded scaffolds became infiltrated with tissue after 6–7 weeks, and infiltrated cells were successfully treated ex vivo. Finally, IO‐loaded scaffolds noninvasively killed infiltrated cells in vivo as evidenced by decreases in number of nuclei. These studies demonstrate the promising use of IO‐loaded scaffolds as a tool for noninvasive hyperthermia, which could be an innovative modality for treatment of disseminated cancers. [ABSTRACT FROM AUTHOR]

Poly(caprolactone; PCL)—poly(N‐isopropylacrylamie; PNIPAAm)—Fe3O4 fiber, that can be magnetically actuated, is reported. Here, a structure is engineered that can be utilized as a smart carrier for the release of chemotherapeutic drug via magneto‐thermal activation, with the aid of magnetic nanoparticles (MNPs). The magnetic measurement of the fibers revealed saturation magnetization values within the range of 1.2–2.2 emu g−1. The magnetic PCL‐PNIPAAm‐Fe3O4 scaffold shows a specific loss power value of 4.19 W g−1 at 20 wt% MNPs. A temperature increase of 40 °C led to a 600% swelling after only 3 h. Doxorubicin (DOX) as a model drug, demonstrates a controllable drug release profile. 39% ± 0.92 of the total drug loaded is released after 96 h at 37 °C, while 25% drug release in 3 h at 40 °C is detected. Cytotoxicity results show no significant difference in cell attachment efficiency between the MNP‐loaded fibers and control while the DOX‐loaded fibers effectively inhibited cell proliferation at 24 h matching the drug release profile. The noncytotoxic effect, coupled with the magneto‐thermal property and controlled drug release, renders excellent potential for these fibers to be used as a smart drug‐release agent for localized cancer therapy. [ABSTRACT FROM AUTHOR]

In the present work, the biodegradable nanofibrous scaffolds containing poly(caprolactone) (PCL), poly(vinyl alcohol) (PVA) and aloe vera (AV), through two nozzles electrospinning method, were prepared and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle measurement and mechanical analysis. The biocompatibility and cell growth were evaluated using MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. Adding poly(vinyl alcohol) (PVA) and poly(caprolactone) (PCL) boosted the electrospinability of aloe vera (AV) solution and mechanical features of the scaffolds. According to the Scanning electron microscopy (SEM) results, uniform PVA/AV-PCL nanofibers were fabricated with the average diameter about 119±11.78 nm. Fourier-transform infrared spectroscopy) FTIR (confirmed the presence of functional groups of scaffolds. The results of the contact angle showed that by adding aloe vera, the hydrophilicity increased. The results showed that the tensile strength of samples with 6 mg/ml AV, reached to 2.02 MPa. MTT results showed that all samples had a cell viability of over 80 %. It can be concluded that nanofibrous scaffolds with concentration of 6 mg/ml, distance between syringe tip/collector of 15 cm, feed rate of 3 ml/h and applied voltage of 12 kV, have appropriate properties for skin tissue engineering by stimulating the fibroblast cells and therefore accelerating the regeneration processes of damaged skin. [ABSTRACT FROM AUTHOR]

Tissue engineering needs versatile methods as a mean to monitor morphological and functional success of the constructs such as scaffolds and implants. In this study, electrospun scaffolds based on poly(caprolactone) (PCL) were fabricated by electrospinning method and seeded by mesenchymal stem cells (MSCs) to investigate the morphological effects on osteogenic differentiation. Prior to cell seeding, substrates were modified and functionalized by increasing porosity via removal of sacrificial component and covalently grafting/adsorption of collagen type 1 (Col I) and nanohydroxy apatite particles (nHA). Images of the alizarin red stained substrate on day 21 of cell culture were obtained and by image processing techniques, extend of mineralization was evaluated. According to the results, mineral compound was more secreted from cells on the scaffolds with higher porosity and covalently functionalized surface. [ABSTRACT FROM AUTHOR]

While highly porous biodegradable sponges have typically been used as tissue engineering scaffolds, they could be applicable in settings requiring drug delivery. Since most drug delivery devices are intentionally solid, nonporous polymers, a detailed structure–function relationship of delivery from a porous degradable sponges would allow researchers to develop such devices for either delivery alone, or in conjunction with tissue engineering. Two fabrication techniques (salt‐leaching and solvent‐quenching) were used to prepare several different variations of poly(DL‐lactide‐glycolide) and poly(caprolactone)‐co‐poly(lactide) porous sponges. Upon fabrication, an in‐depth structure–function analysis was carried out where the functions of loading capacity and release profile of cisplatin, as a model drug, were evaluated in terms of the swelling, porosity, and degradation properties of the sponges. Swelling, pore volume fraction, and the number of pores per volume were all found to be positively correlated with both the loading capacity and amount of cisplatin released after 2 hr. Knowledge of these relationships can be used to assist in the design of other porous delivery systems. [ABSTRACT FROM AUTHOR]

The phase change microcapsule (mPCM) is one of the primary candidates in the fields of energy storage and thermal regulation. In this study, electro-spraying, as a green, high-efficiency electrohydrodynamic atomization technology, is applied to the microencapsulation of two phase change materials (PCM) (n-hexadecane and n-eicosane) with three loading contents (30%, 50%, and 70% by weight) in a polycaprolactone matrix. Ethyl acetate (EA) and chloroform (Chl) were chosen as solvents to prepare the working solutions. The objective of this study is to clarify the microencapsulation process during electro-spraying and to optimize the structure and properties of the electro-sprayed mPCM. The structures, morphologies, and thermal properties of the mPCM were characterized by optical microscopy (OM), scanning electron microscopy (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and fourier transform infrared spectroscopy (FT-IR). Electro-sprayed spherical and non-porous mPCMhave been successfully prepared. The mean diameter and the particle size distribution depend mainly on the choice of the n-alkane, as well as the solvent used to prepare the working solutions. Meanwhile, the structure formation of electro-sprayed mPCM and the loading content of PCM were mainly influenced by the evaporation of the solvent and the phase separation between PCM and poly(caprolactone) (PCL) matrix. During the shell formation or PCL solidification, the control of the PCM leaching out of the matrix allows improving the loading content. Finally, based on a high latent heat and simple formation process, the electro-spraying route of PCM is a green, non-toxic, and high-efficiency direction for energy storage and heat regulation. [ABSTRACT FROM AUTHOR]

In this study, we developed a three-dimensional (3D) in vitro infection model to investigate the crosstalk between phagocytes and microbes in inflammation using a nanofibrous membrane (NM). Poly(ε-caprolactone) (PCL)-NMs (PCL-NMs) were generated via electrospinning of PCL in chloroform. Staphylococcus aureus and phagocytes were able to adhere to the nanofibers and phagocytes engulfed S. aureus in the PCL-NM. The migration of phagocytes to S. aureus was evaluated in a two-layer co-culture system using PCL-NM. Neutrophils, macrophages and dendritic cells (DCs) cultured in the upper PCL-NM layer migrated to the lower PCL-NM layer containing bacteria. DCs migrated to neutrophils that cultured with bacteria and then engulfed neutrophils in two-layer system. In addition, phagocytes in the upper PCL-NM layer migrated to bacteria-infected MLE-12 lung epithelial cells in the lower PCL-NM layer. S. aureus-infected MLE-12 cells stimulated the secretion of tumor necrosis factor-α and IL-1α in 3D culture conditions, but not in 2D culture conditions. Therefore, the PCL-NM-based 3D culture system with phagocytes and bacteria mimics the inflammatory response to microbes in vivo and is applicable to the biomimetic study of various microbe infections.

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• First time shown lipase catalysed grafting of PCL on Cs by reactive extrusion. • Detailed characterization of the copolymers performed to confirm grafting reaction. • Lipase exhibit differences in grafting ratio, yield and functional gr. selectivity. • Antimicrobial activity of Cs against E.coli did not change after grafting of PCL. Chitin is an abundant natural polymer and its deacetylated derivative chitosan has been a focus for the development of biobased, biocompatible and antimicrobial materials. In this work, a green and scalable route to grafting polycaprolactone (PCL) to chitosan using an enzyme catalysed reactive extrusion process is described. FTIR, 1H and 13C NMR spectroscopy and HSQC analysis confirm grafting of PCL to chitosan and show differences in the grafting pattern obtained using two commercially produced lipase enzymes from Candida antarctica (CALB® and NovoCor®). The thermostable NovoCor enzyme gave a much higher grafting yield (96.3%) than the less thermostable CALB enzyme (5.90%). In the esterification reaction, CALB preferentially catalyses reaction on primary OH groups at the C-6 position of chitosan, whereas NovoCor catalyses on the secondary OH groups of chitosan at the C-3 position. This is related to the differences in the selectivity of the two lipase enzymes. The control synthesized without enzyme did not show any grafting reaction. The degree of crystallinity and thermal stability of the lipase catalysed copolymer was reduced compared to unmodified chitosan. Moreover, the PCL grafted chitosan produced by a solvent free reactive extrusion route retained antimicrobial property against E.coli. Such grafted co-polymers may have applications in the controlled release coatings and tissue culture surfaces. [ABSTRACT FROM AUTHOR]

Abstract Advanced wound dressings capable of interacting with lesions and changing the wound microenvironment to improve healing are promising to increase the therapeutic efficacy of this class of biomaterials. Aiming at the production of bioactive wound dressings with the ability to control the wound microenvironment, biomaterials of three different chemical compositions, but with the same architecture, were produced and compared. Electrospinning was employed to build up a biomimetic extracellular matrix (ECM) layer consisting of poly(caprolactone) (PCL), 50/50 dl -lactide/glycolide copolymer (PDLG) and poly(l -lactide) (PLLA). As a post-treatment to broaden the bioactivity of the dressings, an alginate coating was applied to sheathe and functionalize the surface of the hydrophobic electrospun wound dressings, in combination with the extract of the plant Arrabidaea chica Verlot, known for its anti-inflammatory and healing promotion properties. Wettable bioactive structures capable to interact with media simulating lesion microenvironments, with tensile strength and elongation at break ranging respectively from 155 to 273 MPa and from 0.94 to 1.39% were obtained. In simulated exudative microenvironment, water vapor transmission rate (WVTR) values around 700 g/m2/day were observed, while water vapor permeability rates (WVPR) reached about 300 g/m2/day. In simulated dehydrated microenvironment, values of WVTR around 200 g/m2/day and WVPR around 175 g/m2/day were attained. Graphical abstract Unlabelled Image Highlights • Hybrid dressings were electrospun and coated with alginate and a plant extract. • The dressings had a resistant hydrophobic core mimicking the ECM structure. • The biomaterials showed a hydrophilic surface containing Arrabidaea chica extract. • The dressings can potentially interact and alter lesion microenvironment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • In-situ copolymerization blending strategy was provided to prepare POC/PCL composite elastomer. • Crystallization of PCL was suppressed to produce a full-amorphous structure. • Composite elastomer exhibited increased extendibility but avoiding stickiness and fast degradation compared with POC. Abstract Poly(1, 8-octanediol citrate) (POC) degradable elastomer have attracted much attention due to its good biological properties. However, there is a compromise, i.e. to improve its extendibility inevitably leads to a sticky feature that causes inconvenient handling. Poly(ε-caprolactone) (PCL) is a commonly used biodegradable, flexible polyester applied in a variety of FDA-approved products. Here, an in-situ copolymerization blending strategy, i.e. melt polycondensation of citric acid and 1, 8-octanediol in the presence of PCL was adopted to produce a POC/PCL composite elastomer, in which partial PCL took part in polycondensation reaction and chemically bonded into the POC network, and the rest physically traversed within the network structure, leading to a transparent, flexible composite elastomer. The wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) analyses confirmed a full-amorphous structure and no crystallization of PCL occurring. Moreover, the introduction of PCL not only improved extendibility but avoided stickiness. Compared to the POC, the time for curing POC/PCL prepolymers was highly reduced; and the degradation of composite elastomers in PBS solution was accelerated despite the slow degradation of PCL incorporated; additionally, surface erosion degradation presumably happened for POC/PCL elastomers, which would allow the implant to retain inner strength for a longer time. [ABSTRACT FROM AUTHOR]

Biodegradable amphiphilic polyurethane films (bio-PUs) were synthesized by solvent free polyaddition reaction of hydrophilic poly(ethylene glycol) (PEG) and hydrophobic poly(caprolactone) (PCL) as macrodiols with hexamethylene diisocyanate. Samples were subsequently heat cured in order to obtain 3D crosslinked structure. Different PCL/PEG ratios allowed controlling the toughness of the resulting bio-PUs. Significant enhancement of Young’s modulus, strength and elongation at break was observed at a PCL/PEG molar ratio above 3. The change in the bio-PU mechanical behavior was ascribed to the formation of crystalline PCL domains in the bio-PU network. The presence of PEG increased both the ability to absorb water and the rate of hydrolytic degradation, while PCL increased the cell viability. Prepared solvent free bio-PUs may advantageously be used in medicine as elastic resorbable material applicable against post-surgical adhesions.

Ganciclovir (GCV) is a nucleoside analogue with antiviral activity against herpes viral infections, and the most widely used antiviral to treat cytomegalovirus infections. However, the low bioavailability and short half-life of GCV necessitate the development of a carrier for sustained delivery. In this study, guanosine-based GCV was used as the initiator directly in ring-opening polymerization of ε-caprolactone (ε-CL) to form hydrophobic GCV-poly(caprolactone) (GCV-PCL) which was then grafted with hydrophilic chitosan to form amphiphilic copolymers for the preparation of stable micellar nanoparticles. Successful synthesis of GCV-PCL and GCV-PCL-chitosan were verified by 1H-NMR analysis. Self-assembled micellar nanoparticles were characterized by dynamic light scattering and zetasizer with an average size of 117 nm and a positive charge of 24.2 mV. The drug release kinetics of GCV was investigated and cytotoxicity assay demonstrated that GCV-tagged polymeric micelles were non-toxic. Our results showed that GCV could be used directly in the initiation of ring-opening polymerization of ε-CL and non-toxic polymeric micelles for GCV delivery can be formed.

Summary: Fibrous nanomaterials such as electrospun materials have many uses ranging from tissue engineering to biosensors. High‐resolution imaging is an important component in the characterization of these materials. Important parameters required to predict and study the properties of fibre rich materials include diameter and orientation distribution as well as fibre spacing. The orientations and the relative dimensions of the fibres can be measured via specially designed imaging software. Difficulties in this measurement process can arise if fibres are distributed in close proximity to each other in relation to the resolution of the imaging modality. For example, if some automation is required in the measurement process and, particularly, if the automated processes are not designed for situations where the fibres are in close proximity to each other. This work is therefore concerned with the development of automated measurement techniques to provide estimates of the diameters of fibres and also the orientation distribution. The software automatically detects special points in the fibrous materials where fibres can be considered to have some delineation from surrounding fibres. These sparse points are considered to be points at which estimates of the fibres' properties can be quantified. Aligned and randomly distributed electrospun poly(caprolactone) nanofibres were prepared. Imaging of these materials was performed with an X‐ray Computer Tomography system with an image voxel size of 0.15 × 0.15 × 0.15 μm3. Scanning Electron Microscopy images were also obtained. Fibre diameters estimated using images from both modalities using the developed techniques were found to be in agreement. Orientation distribution was summarized with multiscale entropy and found to be consistent with visual observation across different scales. Lay Description: Fibres are present in many types of materials which can include, for some materials, very small fibres e.g. a few nanometres in diameter. Very small fibres are present in collagen and elastin which are common tissues of many organs in many types of living things. The sizes of these very small fibres and how they are arranged are important information that can help in the understanding of the overall properties of these materials. Materials with very small fibres can also be synthesized using specialised techniques. The properties of these synthesized fibrous materials are also important to help in understanding how the materials will perform in various different applications. Applications are many and can range from tissue engineering to drug delivery. Some properties of these materials can be shown, visually, with the aid of 3D imaging techniques such as X‐ray Computer Tomography (XCT) or in 2D, with Scanning Electron Microscopy (SEM) but at a higher magnification. The work described here is centred around the development of computer algorithms to automatically determine material properties from 3D XCT images. Tests are performed with material samples, where the fibres are aligned (in semi‐parallel fashion) and another where the fibres are randomly oriented (criss‐crossing). The tests show that the developed algorithms are able to successfully and relatively accurately determine the diameters of the fibres. The tests also show that it is possible to quantify the relative randomness of the orientations of the fibres. [ABSTRACT FROM AUTHOR]