Amount Of PCL Research Articles

Preparation, Characterization, and Release Profile Study of Vincristine Sulfate-loaded Polycaprolactone Nanoparticles

Background: Vincristine sulfate is commonly used to treat different types of cancers. However, its effectiveness is hindered by undesirable side effects, which significantly limit its applications in medicine. Objective: This study aims to prepare vincristine nanoparticles, in order to develop a promising approach for cancer therapy. Methods: Vincristine nanoparticles were prepared by utilizing polycaprolactone as a carrier through the double emulsion method. The morphological characteristics and particle size of the vincristine nanoparticles were examined. The surface charge and average dynamic size, encapsulation efficiency in addition to release profile study were also evaluated. Results: Dynamic Light Scattering confirmed the small size of nanoparticles (~200 nm). SEM showed spherical-shaped nanoparticles with smooth surfaces, and the polydispersity index values of the prepared nanoparticles were below 0.5 in all preparations. The zeta potential of the nanoparticles was found to be negative, which can be attributed to the presence of carboxylic groups in the PCL polymer, The encapsulation efficiency of Vincristine-loaded nanoparticles (NPs) varied from 36% to 57% for all the prepared NPs with varying amounts of PCL. The release profile demonstrated a prolonged release of Vincristine from the nanoparticles compared to the Vincristine solution. Conclusion: The double emulsion solvent evaporation method was used successfully to prepare vincristine- loaded PCL nanoparticles, which suggests that nanoscale carriers hold promise as effective vehicles for delivering chemotherapeutic agents in the treatment of cancer.

Influence of carbon nanotube functionalization on the physical properties of PCL diol/chitosan blends

AbstractBACKGROUNDChitosan‐poly(ε)caprolactone diol (PCL) blends were studied for food packaging film applications. The mechanical and thermal properties of blend films can be regulated with different amounts of PCL and the addition of a nanofiller could reinforce specific domains in the blend to generate nanocomposites with desirable properties for food packaging. This is evidence of the selective insertion of functionalized carbon nanotubes in either PCL or chitosan domains, depending on the nature of chemical groups and the structure over the surface nanofiller.RESULTSMultiwalled carbon nanotubes (MWNTs) were functionalized with four different dendritic molecules and were tested as nanofillers to reinforce biodegradable films made from 70 to 30, 80 to 20, and 90 to 10 Chitosan‐PCL blends in an effort to explore their effects on the barrier and mechanical properties of the yielded nanocomposites. PCL was obtained by biocatalysis from ɛ‐caprolactone and diethylene glycol and then blended with commercial chitosan. Blends were prepared from a solution of chitosan in acetic acid (2% wt/wt), adding PCL diol in chloroform dropwise under stirring. The MWNTs were modified with several functional groups (tannic acid via no‐covalent functionalization, poly(citric acid), poly(urea‐urethane), and poly(amino‐amido) dendrimer). Nanocomposites were obtained by adding in situ 0.5 wt/wt functionalized MWNTs during the preparation of blends. The structural interactions, morphological, and mechanical features of MWNTs/Blend nanocomposites were studied by Fourier‐transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscope (SEM), field emission scanning electron microscopy (FE‐SEM), and strain–stress testing.CONCLUSIONSPreferential interactions between nanofiller and matrix strongly depend on the nature of the nanofiller and the amount of hydrogen bonding species. It was possible to reinforce a particular domain in the blend to generate nanocomposites with desirable/tunable properties by using complementary chemical groups onto MWNTs surface. © 2023 Society of Chemical Industry (SCI).

Biodegradable blends of thermoplastic waxy starch and poly(ε-caprolactone) obtained by high shear extrusion: Rheological, mechanical, morphological and thermal properties

The aim of this work was to develop polymer blends of plasticized thermoplastic waxy starch (TPS) and poly(ɛ-caprolactone) (PCL) using the largest amount of TPS possible to obtain a biodegradable material motivated by sustainability issues and to replace petrochemical-based polymers with alternatives based on biopolymers. Addition of TPS to other polymers has been used to obtain cheaper and increasingly biodegradable final products. However, TPS presents limited mechanical properties, and mixing with other polymers such as PCL is necessary to overcome these limitations and improve its processability. TPS was processed by extrusion and thermo-compression using 30 wt% glycerol. The blends were suitably processed by extrusion and further injected. The TPS/PCL blends were studied by varying the amount of PCL in a range of 10 wt% in increasing order of addition. Thermal analysis showed that introducing PCL in TPS increased Tonset because of the higher thermal stability of the former, and that the obtained blends presented a behavior intermediate to that of neat polymers.Graphical Abstract

Thermal Mending of Electroactive Carbon/Epoxy Laminates Using a Porous Poly(ε-caprolactone) Electrospun Mesh.

For the first time, a porous mesh of poly(ε-caprolactone) (PCL) was electrospun directly onto carbon fiber (CF) plies and used to develop novel structural epoxy (EP) composites with electro-activated self-healing properties. Three samples, i.e., the neat EP/CF composite and two laminates containing a limited amount of PCL (i.e., 5 wt.% and 10 wt.%), were prepared and characterized from a microstructural and thermo-mechanical point of view. The introduction of the PCL mesh led to a reduction in the flexural stress at break (by 17%), of the interlaminar shear strength (by 15%), and of the interlaminar shear strength (by 39%). The interlaminar fracture toughness of the prepared laminates was evaluated under mode I, and broken samples were thermally mended at 80 °C (i.e., above the melting temperature of PCL) by resistive heating generated by a current flow within the samples through Joule’s effect. It was demonstrated that, thanks to the presence of the electrospun PCL mesh, the laminate with a PCL of 10 wt.% showed healing efficiency values up to 31%.

Electrospinning of ampicillin trihydrate loaded electrospun PLA nanofibers I: effect of polymer concentration and PCL addition on its morphology, drug delivery and mechanical properties

It was aimed to produce ampicillin trihydrate loaded electrospun PLA and PLA/PCL nanofibers using HFIP as solvent. The effect of PLA concentration (7.5–12.5%), PCL addition and added PCL amount (20–80%) on the nanofibers properties were investigated. The increase in PLA concentration caused an increase in nanofiber diameter and a decrease in mechanical properties. PLA nanofibers have shown biphasic controlled drug release up to 10 days, while PCL nanofiber caused only a rapid burst effect. As a result, PLA concentration and the amount of added PCL affected the average nanofiber diameter, in vitro drug release and mechanical properties of the obtained electrospun nanofibers.

Gelatin-based nanofibrous electrically conductive scaffolds for tissue engineering applications

Nanofibrous electrically conductive scaffolds based on gelatin, namely gelatin-grafted polythiophene (Gel-g-PTh) and gelatin-grafted polythiophene/poly(ε-caprolactone) (Gel-g-PTh/PCL), have been designed and fabricated using the electrospinning technique. The performances of the fabricated electrospun nanofibers as scaffolds in tissue engineering (TE) application were preliminarily investigated in terms of some physicochemical as well as biological features. The results revealed that both fabricated electrospun nanofibers have potential as scaffolds for use in TE applications that require electroactivity. It was found that the co-electrospinning of Gel-g-PTh with a small amount of PCL improves the nanofibers’ uniformity as well as some biological characteristics of the resultant scaffold.

Design of electrical conductive poly(lactic acid)/carbon black composites by induced particle aggregation

AbstractThe electrical conductivity of ternary composites composed of a biopolymer blend with conductive particles (carbon black [CB]) is induced by the control of particle dispersion in the dispersed phase. If the CB particles have higher chemical affinity for the secondary phase (poly(caprolactone) [PCL]]) than the matrix (poly(lactic acid) [PLA]), especially as the concentration of the PCL phase decreases significantly to 4 wt%, the PCL phase induces the aggregation of CB particles beyond the selective localization, resulting in a shift of the particle percolation threshold to a lower concentration of particles (2.44 wt% CB). Moreover, the mixing ratio between the CB and the PCL phase significantly affects the formation of percolation of particles. When the mixing ratio of CB to PCL is equivalent (1:1), the ternary composite shows high electrical DC conductivity above 1 S/m with 10 wt% CB. The addition of a small amount of PCL induces the formation of particle aggregates with a high aspect ratio, providing more electron transfer pathways due to the multiple points of contact between the particle aggregates (power law scaling exponent of the composites ~2.14). Meanwhile, a binary composite (PLA/CB) never reaches high electrical conductivity of 1 S/m and even requires a greater concentration of CB (13 wt% CB for 10−3 S/m) to accomplish electron transfer because of the small aspect ratio of randomly dispersed particle aggregates (power law scaling exponent ~3.20).

Threads Made with Blended Biopolymers: Mechanical, Physical and Biological Features.

Poly (Lactic Acid), PLA, and Poly (ε-CaproLactone), PCL, compatibilized with Ethyl Ester l-Lysine Triisocyanate (LTI) can be employed as biomaterials. We mixed PLA with PCL and LTI in a twin extruder and by a melt spinning process obtained threads with an average diameter of about 0.3 mm. In order to study the possible application of these threads, mechanical tensile (with the calorimetric and morphological investigations) and biological tests were performed. The results highlighted these biopolymers as promising materials for sutures since they can be rigid and elastic (especially by increasing the PCL amount in the blend), and they are bioactive, able to inhibit bacterial growth. This paper represents a starting point to optimize the blend composition for biomedical suture application.

Influence of free PCL in PCL/PBA-a copolymers and blends on morphology, thermo-mechanical and shape memory properties

Poly(ε-caprolactone) (PCL) and bisphenol A based polybenzoxazine (PBA-a) blends and copolymers differing in the amount of PCL and bonding mode are reported aiming at studying the role of free PCL. Copolymers containing and lacking free PCL were used to understand the influence of PCLs bonding mode on morphology and mechanical properties. XRD and DSC studies revealed that free PCL in the samples increased the degree of crystallinity in contrast to samples containing similar but bound amounts of PCL. Free PCL tends to phase separate leading to discontinuous phases in the appropriate blends in contrast to smooth surfaces and homogeneous copolymer-like samples as confirmed by AFM and SEM micrographs. Reduced crystallinity due to the absence of free PCL results in a less stabilized network and thereby in a diminished material stiffness. In view of shape memory properties, this study revealed that both a widened network due to covalent PCL incorporation and the existence of free and motile PCL facilitating crystallization are important parameters for the occurrence of shape memory abilities in PCL/PBA-a copolymers.

Tayloring PS/PCL blends: characteristics of processing and properties

Blends of Polystyrene (PS) and Poly(ε-caprolactone) (PCL) were twin screw extruded, two PSs, with low and high melt flow rate (MFR) were used and their feasibility within PCL investigated by means of torque rheometry, mechanical tests, heat deflection temperature (HDT) and scanning electron microscopy (SEM); predictive models were utilized to evaluate interfacial adhesion in PS/PCL blends. Results show that no decreasing was verified in torque rheometry plots suggesting thermally stable blends; elastic modulus decreased and elongation at break increased in PS/PCL blends compared to neat PS. PS/PCL blends with low MFR PS and higher PCL amount are more thermodynamically stable. Higher HDT was verified in PS/PCL blends. The trends observed applying predictive models are indicative of poor adhesion between PCL and PS, agreeing with coalescence and phase segregation as verified in SEM images. PS/PCL systems with higher MFR PS presented the best results.

Preparation of Amylose-Carboxymethyl Cellulose Conjugated Supramolecular Networks by Phosphorylase-Catalyzed Enzymatic Polymerization

Enzymatic polymerization has been noted as a powerful method to precisely synthesize polymers with complicated structures, such as polysaccharides, which are not commonly prepared by conventional polymerization. Phosphorylase is one of the enzymes which have been used to practically synthesize well-defined polysaccharides. The phosphorylase-catalyzed enzymatic polymerization is conducted using α-d-glucose 1-phosphate as a monomer, and maltooligosaccharide as a primer, respectively, to obtain amylose. Amylose is known to form supramolecules owing to its helical conformation, that is, inclusion complex and double helix, in which the formation is depended on whether a guest molecule is present or not. In this paper, we would like to report the preparation of amylose-carboxymethyl cellulose (CMC) conjugated supramolecular networks, by the phosphorylase-catalyzed enzymatic polymerization, using maltoheptaose primer-grafted CMC. When the enzymatic polymerization was carried out using the graft copolymer, either in the presence or in the absence of a guest polymer poly (ε-caprolactone) (PCL), the enzymatically elongated amylose chains from the primers on the CMC main-chain formed double helixes or inclusion complexes, depending on the amounts of PCL, which acted as cross-linking points for the construction of network structures. Accordingly, the reaction mixtures totally turned into hydrogels, regardless of the structures of supramolecular cross-linking points.

Study of the formation of biodegradable polycaprolactone particles using solvent evaporation method

Poly(ε-caprolactone) (PCL), an aliphatic polyester paved the way in the formation of biodegradable and biocompatible polymer particles in tissue engineering and drug delivery applications. The factors affecting in the preparation of PCL particles such as influences of the concentration of PCL, molecular weight and concentration of poly(vinylpyrrolidone) (PVP) stabilizer, and the reaction time on the characteristics of PCL particles were investigated. In the fabrication of PCL particles, size, morphology and stability of the polymer particles were tailored by varying the type and concentration of the stabilizer to the polymer, reaction time and stirring speed of the reaction. Additionally, formation of particles was also related to the amount of PCL and PVP concentration. The PCL particles possessed a spherical shape with the size ranges of 5-20 micron and stability increases with higher concentration of PVP while coagulation observed when PCL particles prepared with the low concentration of PVP. The change in the morphology and sizes of the PCL particle at different reaction conditions were evaluated by scanning electron microscopy (SEM) analysis.

Thermal behavior and structural study of ZrO2/poly(ε-caprolactone) hybrids synthesized via sol-gel route

The thermal behavior of pure ZrO2 and four ZrO2-based organic-inorganic hybrids (OIHs) containing increasing amount (6, 12, 24 and 50 wt%) of poly(ε-caprolactone) (PCL) (named Z, ZP6, ZP12, ZP24 and ZP50 respectively) has been studied by simultaneous thermogravimetry (TG) and differential scanning calorimetry (DSC). The FTIR analysis of the gas mixture evolved at defined temperatures from the samples submitted to the TG experiments identified the mechanism of each thermally activated process. The obtained results suggest that the inorganic matrix of the OIHs prepared by this method exerts a stabilizing effect on the polymer, in particular for poor-PCL hybrid materials. In fact, the different thermal behavior of the ZP50 sample suggests that the polymer is not entirely bonded to the -OH groups of the zirconia matrix due to their saturation. For this reason a part of PCL is not affected by the stabilizing effect of the matrix and is subjected to thermal degradation. Finally, by observing their thermal behavior it was possible to select the most suitable temperatures for thermal pretreatment: 400, 600 and 1000 °C. The structural analysis by X-ray diffraction (XRD) revealed that at 400 °C the materials are amorphous, while at 600 °C they are mostly tetragonal, and the content of the tetragonal phase decreases with increasing the amount of PCL in the OIHs. All the materials treated at 1000 °C are monoclinic, but their crystallinity decreases with increasing the PCL content.

Preparation of supramolecular network materials by means of amylose helical assemblies

Amylose, a natural polysaccharides, is a well-known functional material, because it forms double helix and inclusion complex assemblies depending on whether guest compounds are present or not, owing to its left-handed helical conformation. Amylose is precisely synthesized by phosphorylase-catalyzed enzymatic polymerization. In this study, we investigated the phosphorylase-catalyzed enzymatic polymerization initiated from maltoheptalose (primer for the polymerization)-grafted poly(γ-glutamic acid) in the presence of different feed ratios of a guest polymer, poly(ε-caprolactone) (PCL). In the absence of PCL or presence of less amount of PCL, the reaction mixtures totally turned into hydrogel form, predominantly composed of amylose double helixes. On the other hand, aggregates, which were largely composed of amylose inclusion complexes, were formed in the reaction mixtures in the presence of larger amount of PCL. The analytical results indicated that double helix cross-linking points participated into the formation of larger network structure, whereas smaller network structure was fabricated from inclusion complex cross-linking points. These structures on molecular level hierarchically constructed different macroscopic network sizes, leading to difference in the material forms.

Self-healing properties of epoxy resins with poly(ε-caprolactone) healing agent

Thermally induced healing through thermoplastic poly(e-caprolactone) (PCL), dissolved in 12.5, 25, 37.5 and 50 wt%, respectively, in amine-cured epoxy resins (EPs) was studied on compact tension (CT) specimens. Aromatic (hydrogenated diglycidyl ether of bisphenol A-type) and aliphatic (glycerol-triglycidylether) EPs were cured with the same amine (Jeffamine D 230) to receive EPs with different glass transition temperatures (T g). T g values of the parent EPs were lower (T g = 32 °C) and higher (T g = 90 °C), respectively, than the melt temperature (T m ≈ 60 °C) of the PCL. The curing-induced phase separation morphology of PCL was studied by light microcopy. Additional information on the phase structure was deduced from dynamic mechanical analysis. Blending with PCL reduced the T g of the corresponding EPs. Fully broken CT specimens were repeatedly healed at 80 °C which was close to or higher than the actual T g of the EP/PCL blend. It was found that the transition of PCL from disperse to continuous phase depends not only on the PCL amount, but also on the EP type and its curing. EP/PCL systems with semi-interpenetrating network structure (bi-continuous) exhibited markedly higher healing efficiencies compared to those in which PCL was present as disperse phase. The healing efficiency depended also on the temperature difference between the healing temperature and T g of the EP with respect to T m of PCL. When T g > T m then the related difference should be kept small, while for T g < T m the temperature difference should be large to support healing. Accordingly, the segmental mobility within the cross-linked EP network is a key parameter for thermal mending, too.

Surface modifications of titanium implants by coating with bioactive and biocompatible poly (ε-caprolactone)/SiO2 hybrids synthesized via sol–gel

Class I organic/inorganic hybrid materials have been synthesized by sol–gel method from a multicomponent solution containing tetraethyl orthosilicate (TEOS), water, ethanol and nitric acid by adding different percentages of poly (ε-caprolactone) (PCL) dissolved in chloroform. Those hybrids have been used, in sol phase, to dip coat commercially pure titanium (CP Ti) grade 4 substrates with the aim of transferring to them the known biological properties of silica-based sol–gel materials. Particular attention has been directed to investigate the effect of PCL amount on both structure and coating performances.The chemical composition of the films was ascertained by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis. Scanning electron microscope (SEM) proved that polymer allows to make crack-free coatings.The biological performances of the un-coated and coated substrates were compared and evaluated by means of bioactivity test and WST-8 assay. SEM and energy dispersive X-ray (EDX) analyses have detected higher hydroxyapatite nucleation on the surface of the coated substrates after soaking in a fluid simulating the composition of the human blood plasma (SBF). Moreover, higher vitality of NIH 3T3 mouse embryonic fibroblast cells seeded on coated specimens was recorded. The results, thus, prove that coating application effectively improves the bioactivity and biocompatibility of CP Ti grade 4 substrates.

Preparation and characterization of Rana chensinensis skin extract/poly(ε‐caprolactone) electrospun membranes as antibacterial fibrous mats

ABSTRACTIn this study, membranes composed of Rana chensinensis skin extracts (RCSEs) and poly(ε‐caprolactone) (PCL) were fabricated by an electrospinning technique. The RCSEs were prepared by the extraction of R. chensinensis skin with acetic acid solution, and the electrospun membranes were prepared by the mixture of RCSEs and PCL in 1,1,1,3,3,3‐hexafluoro‐2‐propanol before electrospinning. The membranes were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy and were subjected to mechanical tests (tensile and nanoindentation) and antibacterial evaluation. The results indicate that the surface roughness of the fibers clearly decreased with the increase in the amount of PCL in the membranes. The mechanical test indicated that PCL played a dominant role in the mechanical strength of the RCSE/PCL electrospun membranes. As a potential bactericidal packaging material for practical applications, the antibacterial activity results indicate that the membranes had antibacterial effects against Staphylococcus aureus and Escherichia coli. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42030.

TiO2/PCL hybrid materials synthesized via sol-gel technique for biomedical applications.

The aim of the present work has been the synthesis of organic/inorganic hybrid materials based on titanium dioxide and poly(ε-caprolactone) (PCL) to be used in the biomedical field. Several materials have been synthesized using sol-gel methods by adding different amounts of polymer to the inorganic sol. The obtained gels have been characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The FT-IR data allowed us to hypothesize that the structure formed was that of an interpenetrating network, realized by hydrogen bonds between TiOH groups in the sol-gel intermediate species and carbonyl groups in the polymer repeating units. SEM and AFM analyses highlighted that the obtained materials were nanostructurated hybrids. To evaluate the biological properties of the hybrids, their bioactivity and cytotoxicity were investigated as a function of the PCL amount. The bioactivity of the synthesized systems was proven by the formation of a hydroxyapatite layer on the surface of samples soaked in a fluid simulating human blood plasma (SBF). MTT cytotoxicity tests and Trypan Blue dye exclusion tests were carried out exposing NIH-3T3 mouse embryonic fibroblasts for 24 and 48h to extracts from the investigated hybrid materials. The results showed that all the hybrids had a non-cytotoxic effect on target cells.

Effect of Surface Grafted Hydroxyapatite on the Improved Performance of Hydroxyapatite/Poly(&amp;#949;-caprolactone) Scaffold

Hydroxyapatite nanoparticles (HAP) were surface-grafted with poly(ε-caprolactone) (PCL) using two types of hydroxyl groups: inherent hydroxyl groups within HAP and hydroxyl groups of poly(2-hydroxyethyl methacrylate) (PHEMA) grafted on the HAP surface by atom transfer radical polymerization (ATRP). The grafting efficiency and the amount of grafted polymer were evaluated by thermal gravimetric analysis (TGA). The colloidal stability testing suggested that the surface-grafted HAP retained higher dispersibility in methylene chloride than pure HAP nanoparticles did. Moreover, the dispersity of the modified particles was significantly improved with the increasing amount of PCL grafted. The composite scaffolds of PCL and surface-grafted HAP exhibited enhanced compressive strength and modulus, which was attributed to the increased interfacial interaction between PCL and surface-modified HAP. In particular, it was found that the compressive modulus of the surface-grafted HAP with 47.2 wt% PCL was 91.6% higher than that of pure HAP mixed with PCL scaffold. Keywords: Dispersity, hydroxyapatite, mechanical property, Poly(ε-caprolactone), surface grafted.

Distorted ring-banded spherulites in poly(l-lactic acid)/poly(ε-caprolactone) blends

Unique distorted ring bands with wrinkles and concentric structures in blends of poly(L-lactic acid) (PLLA)/poly(e-caprolactone) (PCL) were obtained by two-step isothermal crystallization and investigated by using polarized optical microscopy (POM) and atomic-force microscopy (AFM). Peculiar morphologies were revealed while the blends were crystallized by two-step crystallization with a fixed first crystallization temperature of 117 °C and different second crystallization temperatures. From the microscopy results, the morphology as the alternating ridges and valleys of wrinkle bands along with concentric ring bands can be resolved. The PLLA crystals could result in the structures of wrinkle bands and small concentric ring bands at the first crystallization temperature. Furthermore, formation of the alternating ridges and valleys of wrinkle bands could be suggested to be attributed to the different amounts of PCL inserted into the pre-formed crystals of PLLA while crystallizing the blends under a lower second crystallization temperature with fast crystallization of PCL. On the other hand at a higher second crystallization temperature, the wrinkle band changed to a branch-like band. PCL chains with high mobility could be sufficiently diffused and uniformly inserted into the pre-formed crystals of PLLA to generate more perfect crystals of PCL at the higher second crystallization temperature. The wrinkle bands with a significant ridge and valley structure vanished by changing the second crystallization to a higher one.