Polycaprolactone Polymer Research Articles

Development of a novel smart carrier for drug delivery: Ciprofloxacin loaded vaterite/reduced graphene oxide/PCL composite coating on TiO2 nanotube coated titanium

In the field of orthopaedic implants, post-surgery infections and biocompatibility are the most challenging obstacles. Sustained and controlled antibiotic release is a key factor in novel drug delivery systems. A novel drug delivery system combined with vaterite microsphere, graphite oxide (GO), reduced graphene oxide (rGO) incorporated in a polycaprolactone (PCL) matrix on TiO2 nanotube coated Ti (TNT-Ti) is established. Anodization was employed to develop TiO2 nanotubular arrays on Ti. Ciprofloxacin hydrochloride (CPF–HCl) loaded vaterite microspheres were synthesized by in situ precipitation method. Deposition of vaterite/PCL, vaterite-GO/PCL and vaterite-rGO/PCL composite coating on TNT-Ti was carried out by dip coating method. The composite coatings were characterized for their phase content, morphological features and functional groups. Among the three types of composite coatings, vaterite-rGO/PCL composite coating is found to be capable of encapsulating CPF-HCl to a level of 75.14 μg. The drug release profile of CPF-HCl from the vaterite-rGO/PCL composite coating exhibits a controlled release amounting to only 35.02 % of release at the end of 120 h. The vaterite-rGO/PCL composite coating exhibits a low dissolution rate and possesses adequate bioactivity in HBSS and SBF solutions at 37 °C for 14 and 10 days, respectively. The in situ loaded CPF-HCL drug on vaterite microspheres, PCL polymer matrix and GO/rGO nanofillers does not affect the cytocompatibility and all the composite coatings supported cell viability and proliferation. The ability of vaterite-rGO/PCL composite coating to provide a slow and steady release of antibiotics with sufficient bioactivity and biocompatibility at the tissue implant interface makes it a promising for osteomyelitis infection of bone tissue implant materials.

Silk fiber-based composite nanofiber tissue scaffold produced with electrospinning method.

Wound dressings are one of the most rapidly expanding areas in medical textiles. In recent years, a large number of functional wound dressing has been developed. The aims of these products are to speed up the wound healing process and to provide maximum comfort for patients. Today, the multidisciplinary studies are required to improve further existed wound dressings. The results of such research studies are also promised new hopes for the Turkish textile industry weakened by the global competition. For this purpose, three different polymers were selected as silk fibroin (SF) / polycaprolactone (PCL) / polyethylene oxide (PEO). The productions were made using triple and doublex mixture polymers and single polymer. It has been observed that the SF/PCL/PEO solution has extremely good viscosity, and conductivity values, fiber diameter, and structure thickness have the highest values. SF/PCL/PEO structure has a middle level in the strength value. It has been observed that the PCL polymer plays an effective role in the strength value. The most effective result for S group mats was seen in S2 (PCL/PEO) mat with a 2.62% reduction against the HaCaT cell line. A nanofiber tissue scaffold was produced by the electrospinning method, and a structured candidate for use was obtained by improving performance.

Control Release Coating for Urinary Catheters with Enhanced Released Profile for Sustained Antimicrobial Protection.

Catheter-associated urinary tract infections (CAUTIs) are common and pose significant costs to healthcare systems. To date, this problem is largely unsolved as commercially available antimicrobial catheters are still lacking in functionality and performance. A prior study by Lim et al. ( Biotechnol. Bioeng. 2018, 115 (8), 2000-2012) reported the development of a novel anhydrous polycaprolactone (PCL) polymer formulation with controlled-release functionality for antimicrobial peptides. In this follow-up study, we developed an improved antimicrobial peptide (AMP)-impregnated poly(ethylene glycol) (PEG)-polycaprolactone (PCL) anhydrous polymer coating for enhanced sustained controlled-release functionality to provide catheters with effective antimicrobial properties. Varying the ratio of PEG and PEG-PCL copolymers resulted in polymers with different morphologies, consequently affecting the AMP release profiles. The optimal coating, formulated with 10% (w/w) PEG-PCL in PCL, achieved a controlled AMP release rate of 31.65 ± 6.85 μg/mL daily for up to 19 days, with a moderate initial burst release. Such profile is desired for antimicrobial coating as the initial burst release acts as a sterilizer to kill the bacteria present in the urinary tract upon insertion, and the subsequent linear release functions as a prophylaxis to deter opportunistic microbial infections. As a proof-of-concept application, our optimized coating was then applied to a commercial silicone catheter for further antibacterial tests. Preliminary results revealed that our coated catheters outperformed commercial silver-based antimicrobial catheters in terms of antimicrobial performance and sustainability, lasting for 4 days. Application of the controlled-release coating also aids in retarding biofilm formation, showing a lower extent of biofilm formation at the end of seven inoculation cycles.

Repair of critical-size porcine craniofacial bone defects using a collagen–polycaprolactone composite biomaterial

Regenerative medicine approaches for massive craniomaxillofacial (CMF) bone defects face challenges associated with the scale of missing bone, the need for rapid graft-defect integration, and challenges related to inflammation and infection. Mineralized collagen scaffolds have been shown to promote mesenchymal stem cell osteogenesis due to their porous nature and material properties, but are mechanically weak, limiting surgical practicality. Previously, these scaffolds were combined with 3D-printed polycaprolactone (PCL) mesh to form a scaffold-mesh composite to increase strength and promote bone formation in sub-critical sized porcine ramus defects. Here, we compare the performance of mineralized collagen–PCL composites to the PCL mesh in a critical-sized porcine ramus defect model. While there were no differences in overall healing response between groups, our data demonstrated broadly variable metrics of healing regarding new bone infiltration and fibrous tissue formation. Abscesses were present surrounding some implants and PCL polymer was still present after 9–10 months of implantation. Overall, while there was limited successful healing, with 2 of 22 implants showed substantial levels of bone regeneration, and others demonstrating some form of new bone formation, the results suggest targeted improvements to improve repair of large animal models to more accurately represent CMF bone healing. Notably, strategies to increase osteogenesis throughout the implant, modulate the immune system to support repair, and employ shape-fitting tactics to avoid implant micromotion and resultant fibrosis. Improvements to the mineralized collagen scaffolds involve changes in pore size and shape to increase cell migration and osteogenesis and inclusion or delivery of factors to aid vascular ingrowth and bone regeneration.

Synthesis and Characterization of Polymeric Microspheres Template for a Homogeneous and Porous Monolith.

Monolith is an emerging technology applicable for separation, filtration, and chromatography due to its interconnected pore structure. However, the current templates used to form monolith pores are associated with poor heat dissipation, uneven pore size distribution, and relatively low mechanical strength during monolith scale-up. Templates made from polymeric microsphere particles were synthesized via a solvent evaporation technique using different types of polymer (polystyrene, polycaprolactone, polypropylene, polyethylene, and poly (vinyl-alcohol) at varied polymer (10–40 wt%) and surfactant (5–10%) concentrations. The resulting microsphere particles were tested as a monolith template for the formation of homogenous pores. Among the tested polymers, polystyrene at 10 wt% concentration demonstrated good particle morphology determined to around 1.94–3.45 µm. The addition of surfactant at a concentration of 7–10 wt% during microsphere synthesis resulted in the formation of well-shaped and non-aggregating microsphere particles. In addition, the template has contributed to the production of porous monoliths with enhanced thermal stability. The thermogravimetric analysis (TGA) indicated monolith degradation between 230 °C and 450 °C, implying the material excellent mechanical strength. The findings of the study provide insightful knowledge on the feasibility of polymeric microsphere particles as a pore-directing template to fabricate monoliths with desired pore structures.

Nanoengineered Antiviral Fibrous Arrays with Rose-Thorn-Inspired Architectures

Herpes simplex virus (HSV) plagues billions of humans with infections globally. We have developed and demonstrated rose-thorn-inspired antiviral fibrous arrays by electrospinning a composite of polycaprolactone (PCL) polymer with a dispersion of anisotropic zinc oxide tetrapod nanoparticles (ZOTeN). This rose-thorn-mimicking material enables physical and chemical protection. Under blue-light stimulation, ZOTeN photocatalyzes the production of hydrogen peroxide for an accessible disinfection and sterilizing mechanism to prolong materials usage. Using scanning electron microscopy and X-ray photoelectron spectroscopy, we confirm the rose-thorn-inspired morphology and the chemical composition, respectively. The fibrous material has dose-dependent antiviral properties against both HSV-1 and HSV-2. The engineered mats can potentially be used for manufacturing antiviral garments, face coverings, and bandages.

Effect of an Antioxidant Based on Red Beetroot Extract on the Abiotic Stability of Polylactide and Polycaprolactone.

This study investigated the effect of natural antioxidants inherent to beetroot (Beta vulgaris var. Vulgaris) on the ageing of environmentally friendly plastics. Certain properties were examined in this context, comprising thermal, mechanical, and morphological properties. A visual evaluation of relevant changes in the given polymers (polylactide and polycaprolactone) was conducted during an ageing test in a UV chamber (45 °C, 70% humidity) for 720 h. The films were prepared by a casting process, in which samples with the extract of beetroot were additionally incorporated in a common filler (bentonite), this serving as a carrier for the extract. The results showed the effect of the incorporated antioxidant, which was added to stabilize the biodegradable films. Its efficiency during the ageing test in the polymers tended to exceed or be comparable to that of the reference sample.

Energy harvesting with flexible piezocomposite fabricated from a biodegradable polymer

Technological advancement is generating a heap of electronic waste and has put onus on the production of wearable electronic systems to be environmentally sustainable without compromising much with their functionality. Many such systems employ flexible piezo sensors for force sensing and/or energy harvesting. In this work, we demonstrate the feasibility of fabricating a flexible piezoelectric energy harvester and sensor by reinforcing a biodegradable polymer polycaprolactone (PCL) with powders of ferroelectric-based piezoceramic systems PbTiO3–Bi(Zr0.5Ni0.5)O3 (PT-BNZ) and 1. The output volume power density of PCL-PTBNZ and PCL-BST was found to be 98.5 and 17 μW/cm3, respectively, for solenoid plunger pressure impact. The corresponding values in the tapping mode are 2556 and 1505 μW/cm3, respectively. The power output derived is significant and can be used to power micro and nano size electronic devices. Such composites can provide a better environment friendly and sustainable alternative to the current piezo energy harvesters.

Honokiol-Loaded Methoxy Poly (Ethylene Glycol) Polycaprolactone Micelles for the Treatment of Age-Related Macular Degeneration.

Age-related macular degeneration (AMD), a multifactorial age-related retinal hypoxic disorder resulting in irreversible loss of vision, is the foremost cause of blindness in the United States. Current treatment strategies involve multiple intraocular injections of antivascular endothelial growth factor (VEGF) agents into the vitreous of eye. In addition to the challenges of drug localization and targeted delivery, the need of frequent injections into the eye raises patient compliance issues, and thus call for development of sustained drug delivery systems. In this study, a sustained drug delivery system was prepared by loading an antihypoxia-induced factor (HIF) agent, honokiol (HON), into methoxy poly (ethylene glycol) polycaprolactone (MPEG-PCL) polymer. These HON-MPEG-PCL micelles were characterized by evaluating size, ζ potential, in vitro drug release profile, and morphology by transmission electron microscopy. The cytotoxic nature of developed micelles was assessed on human retinal pigment epithelial cell line (ARPE-19) cells by cytotoxicity assay. The cellular uptake and HIF and VEGF expression levels were determined in in vitro settings. Micelles formed had a particle size of 30.8 ± 0.8 nm with the poly dispersity index of 0.19 ± 0.0004 and ζ potential was found to be -5.46 ± 0.49 mv. Entrapment efficiency was calculated to be 64 ± 0.135%. In vitro drug release showed sustained release of drug from the formulation. Result from in vitro cytotoxicity study confirmed noncytotoxic nature of HON-MPEG-PCL micelles compared to HON drug solution. Furthermore, enzyme-linked immunosorbent assay studies performed showed the periodic downregulation of HIF and VEGF, which are major growth factors involved in underlying mechanism of AMD. The results showed successful development of HON-MPEG-PCL micelles, which may be useful for the effective treatment of AMD.

Thermoresponsive Poly (N‐Isopropylacrylamide)/Polycaprolacton Nanofibrous Scaffolds for Controlled Release of Antibiotics

Smart antibacterial materials capable of releasing antibiotic drugs upon exposure to external triggers are highly desired for various medical applications. Herein, the fabrication of thermosensitive drug‐loaded core−shell nanofibers using the electrospinning technique combined with in situ UV photopolymerization is reported on. The electrospinning method is used for shaping the core structure comprising biodegradable polymer polycaprolactone (PCL). The PCL fibers are coated with the temperature‐responsive poly‐N‐isopropylacrylamide (PNIPAM) via a UV photopolymerization process that allows to precisely control the shell thickness as verified by transmission electron microscope (TEM) analysis. The temperature‐dependent switchable wettability of prepared core−shell fibers is investigated and visualized though water contact angle measurements below and above the lower critical solution temperature. Loading of the antibiotic drug doxycycline hyclate (Doxy) in the PCL core nanofibers results in drug‐encapsulating fiber meshes that allow diffusion of drug molecules through the PNIPAM shell in a temperature‐dependent manner. The antibacterial activity is examined using Gram‐negative Escherichia coli (E. coli) as well as Gram‐positive Staphylococcus aureus (S. aureus) bacteria. The results demonstrate the high suitability of prepared biocompatible electrospun core−shell PCL/PNIPAM nanofibers as carriers for antibiotic drugs with temperature‐sensitive release behavior.

In vitro Corrosion Behavior and Biological Properties of Magnesium- Zinc-Calcium Alloy Coated with Polycaprolactone Nanofibers

Magnesium alloys have received great attention for the medical applications due to their desired properties.But the main problem of magnesium alloys is the high rate of degradation which provides not enough time for healing.Therefore, in this study, it was tried to control the corrosion rate of Mg-Zn-Ca alloy by applying a nanofiber of polycaprolactone polymer coating and investigate the behaviors such as biocompatibility and rate of degradation. For this purpose, the polymer nanofibers were prepared by electrospinning method and applied on the surface of magnesium-zinc (4 wt. %) -calcium (2 wt. %) alloy, and the corrosion behavior and biological properties were compared with the uncoated alloy. corrosion behavior was measured with Tafel polarization test as well as hydrogen test in body fluid simulation solution, measurement of the pH of the solution after sample destruction, wettability angle test, cytotoxicity test and cell adhesion test.The Tafel polarization test showed that the applied coating increased the corrosion potential from -1.5 to -0.6 volts and corrosion rate reduced by about two order of magnitudes. The amount of hydrogen emitted by the corrosion reaction in the coated sample was much less than that of the uncoated sample. Biocompatibility test showed that the cytotoxicity of the coated sample was 8% lower than that of the uncoated sample. In the cell adhesion test, it was observed that far more cells adhered onto the surface of the coated sample compared to the uncoated sample. The wettability angle on the surface of the coated sample was 128° while that of the uncoated sample was 100°, due to the inherent hydrophobicity of this polymer. Despite the hydrophobicity of polycaprolactone polymer, which is not favorable for cell growth, due to the high biocompatibility of this polymer, coating Mg alloys with this method and material could have some advantages for future implants.

Finite element modeling of electromagnetic properties of 3D printed materials in X‐band spectrum

AbstractMicrowave absorbers are distinctive class of materials, which are used to absorb undesired electromagnetic waves in the microwave spectrum. A finite element modeling approach was utilized in the present study to investigate the microwave absorption properties of three different materials such as polycaprolactone (PCL) polymer, polycaprolactone‐carbonyl iron particle (CIP) composite with random orientation of CIPs, and polycaprolactone‐carbonyl iron particle composite with oriented chain structures of CIPs, fabricated by extrusion‐based 3D printing process. A two‐dimensional model was formulated comprising the material under test and two rectangular waveguides attached to the vector network analyzer. A two‐port network model was used to emulate the real‐time experimental environment. It was found from the electric field distribution plot that the oriented PCL‐CIP model reflects and transmits marginal amplitude of electromagnetic waves when compared with nonoriented PCL‐CIP model followed by pure PCL model. The simulation results were validated with the experimental findings. A minimum loss of electromagnetic energy was observed for oriented model as compared to other models, supporting the experimental findings. Larger domain wall motions and micro capacitor behavior of oriented chains of carbonyl particles were responsible for such microwave absorption properties of oriented composites. The practical utility of the present modeling and simulation approach is multifold as it can be utilized to investigate and compare the electromagnetic shielding behavior of various polymeric composites without any material wastage, machine utilization, and physical testing.

An electro-spun tri-component polymer biomaterial with optoelectronic properties for neuronal differentiation

Optoelectronic biomaterials have recently emerged as a potential treatment option for neurodegenerative diseases, such as optic macular degeneration. Though initial works in the field have involved bulk heterojunctions mimicking solar panels with photovoltaics (PVs) and conductive polymers (CPs), recent developments have considered abandoning CPs in such systems. Here, we developed a simple antioxidant, biocompatible, and fibrous membrane heterojunction composed of photoactive polymer poly(3-hexylthiophene) (P3HT), polycaprolactone (PCL) and polypyrrole (PPY), to facilitate neurogenesis of PC-12 cells when photo-stimulated in vitro. The photoactive prototype, referred to as PCL-P3HT/PPY, was fabricated via polymerization of pyrrole on electro-spun PCL-P3HT nanofibers to form a membrane. Four experimental groups, namely PCL alone, PCL/PPY, PCL-P3HT and PCL-P3HT/PPY, were tested. In the absence of the CP, PCL-P3HT demonstrated lower cell survival due to increased intracellular reactive oxygen/nitrogen species production. PCL-P3HT/PPY rescued these cells by virtue of scavenging radicals, where the CP, PPY, acted as an antioxidant. Apart from having lower impedance, the material also enhanced neurogenesis of PC-12 cells when photo-stimulated, compared to the traditional PCL-P3HT. Lastly, the in vitro system with PC-12 was used to demonstrate the practicality of the material for potential use as a cellular patch in optic and nerve regeneration. This work demonstrated the importance of maintaining PV-CP heterojunctions while simultaneously providing an optoelectrical platform for neural and optical tissue engineering. Statement of significanceRegeneration and repair of injured nervous systems have always been a major clinical challenge. Stem cell therapy is a promising approach for nerve regeneration, and opto-electrical stimulation, which converts light into an electrical signal, has been shown to efficiently regulate stem cell behaviors with enhanced neurogenesis. We developed a micro-fibrous membrane, composed of photoactive polymer, P3HT, scaffold material PCL and conductive polymer PPY. Our heterojunction system improved cell survival via PPY quenching PCL-P3HT-generated cell-damaging reactive oxygen species. PPY also conducted electrons produced from light-stimulated P3HT to promote neurogenesis. This photoactive microfiber biomaterial has great potential as a highly biocompatible and efficient platform to wirelessly promote neurogenesis and survival. Our approach thus showed possibilities with respect to optical tissue engineering.

Biomimetic Scaffolds with a Mineral Gradient and Funnel-Shaped Channels for Spatially Controllable Osteogenesis.

A facile method is described herein for generating a mineral gradient in a biodegradable polymer scaffold. The gradient is achieved by swelling a composite film made of polycaprolactone (PCL) and hydroxyapatite (HAp) nanoparticles with a PCL solution. During the swelling process, the solvent and PCL polymer chains diffuse into the composite film, generating a gradient in HAp density at their interface. The thickness of the mineral gradient can be tuned by varying the extent of swelling to match the length scale of the natural tendon-to-bone attachment (20-60 µm). When patterned with an array of funnel-shaped channels, the mineral gradient presents stem cells with spatial gradations in both biochemical cues (e.g., osteoinductivity and conductivity associated with the HAp nanoparticles) and mechanical cues (e.g., substrate stiffness) to stimulate their differentiation into a graded distribution of cell phenotypes. This new class of biomimetic scaffolds holds great promise for facilitating the regeneration of the injured tendon-to-bone attachment by stimulating the formation of a functionally graded interface.

Encapsulation of Nerol Oil in Polycaprolactone Polymer and Stability Evaluation

The objective of this study was to obtain and characterize Nerol essential oil encapsulated in PCL. The miniemulsion and solvent evaporation method was used, resulting in PCL-Nerol capsules bonded by a physical interaction, with a dispersity index of 0.101, a particle size of 0.14 µm, and an encapsulation efficiency of 94.27%. In addition, the temperature at which the oil degraded could be observed to increase by 100 °C when it is encapsulated in PCL, revealing this polymer's capacity in working as an encapsulating agent. The PCL-Nerol capsules in suspension proved to be stable for 60 days regarding the pH of the suspensions, mean particle size, dispersity index, zeta potential and the encapsulation efficiency, not presenting clusters and flocculation. The results are considered satisfactory and important for the future industrial applications of the obtained microparticles.

Polymer-Coated and Nanofiber-Reinforced Functionally Graded Bioactive Glass Scaffolds Fabricated Using Additive Manufacturing.

In this study, carbon nanotube (CNT) reinforced functionally graded bioactive glass scaffolds have been fabricated using additive manufacturing technique. Sol-gel method was used for the synthesis of the bioactive glass. For ink preparation, Pluronic F-127 was used as an ink carrier. The CNT-reinforced scaffolds were coated with the polymer polycaprolactone (PCL) using dip-coating method to improve their properties further by sealing the micro-cracks. The CNT- reinforcement and polymer coating resulted in an improvement in the compressive strength of the additively manufactured scaffolds by 98% in comparison to pure bioactive glass scaffolds. Further, the morphological analysis revealed interconnected pores and their size appropriate for osteogenesis and angiogenesis. Evaluation of the in vitro bioactivity of the scaffolds after immersion in simulated body fluid (SBF) confirmed the formation of hydroxyapatite (HA). Further, the cellular studies showed good cell viability and initiation of osteogensis. These results demonstrate the potential of these scaffolds for bone tissue engineering applications.

Polymer-coated microparticle scaffolds engineered for potential use in musculoskeletal tissue regeneration

Biomaterials constructed exclusively of sintered microspheres have great potential in tissue engineering scaffold applications, offering the ability to create shape-specific scaffolds with precise controlled release yet to be matched by traditional additive manufacturing methods. The problem is that these microsphere-based scaffolds are limited in their stiffness for applications such as bone regeneration. Our vision to solve this problem was borne from a hierarchical structure perspective, focusing on the individual unit of the structure: the microsphere itself. In a core–shell approach, we envisioned a stiff core to create a stiff microsphere unit, with a polymeric shell that would enable sintering to the other microsphere units. Therefore, the current study provided a comparison of macroscopic biomaterials built on either polymer microspheres or polymer-coated hard glass microspheres. Identical polycaprolactone (PCL) polymer solutions were used to fabricate microspheres and as a thin coating on soda lime glass microspheres (hard phase). The materials were characterized as loose particles and as scaffolds via scanning electron microscopy, thermogravimetry, differential scanning calorimetry, Raman spectroscopy, mechanical testing, and a live/dead analysis with human umbilical cord-derived Wharton’s jelly cells. The elastic modulus of the scaffolds with the thinly coated hard phase was about five times higher with glass microspheres (up to about 25 MPa) than pure polymer microspheres, while retaining the structure, cell adhesion, and chemical properties of the PCL polymer. This proof-of-concept study demonstrated the ability to achieve at least a five-fold increase in macroscopic stiffness via altering the core microsphere units with a core–shell approach.

Conversion of Cyclohexane to 6-Hydroxyhexanoic Acid Using Recombinant Pseudomonas taiwanensis in a Stirred-Tank Bioreactor

6-hydroxyhexanoic acid (6HA) represents a polymer building block for the biodegradable polymer polycaprolactone. Alternatively to energy- and emission-intensive multistep chemical synthesis, it can be synthesized directly from cyclohexane in one step by recombinant Pseudomonas taiwanensis harboring a 4-step enzymatic cascade without the accumulation of any intermediate. In the present work, we performed a physiological characterization of this strain in different growth media and evaluated the resulting whole-cell activities. RB and M9* media led to reduced gluconate accumulation from glucose compared to M9 medium and allowed specific activities up to 37.5 ± 0.4 U gCDW−1 for 6HA synthesis. However, 50% of the specific activity was lost within 1 h in metabolically active resting cells, specifying growing cells, or induced resting cells as favored options for long-term biotransformation. Furthermore, the whole-cell biocatalyst was evaluated in a stirred-tank bioreactor setup with a continuous cyclohexane supply via the gas phase. At cyclohexane feed rates of 0.276 and 1.626 mmol min−1 L−1, whole-cell biotransformation occurred at first-order and zero-order rates, respectively. A final 6HA concentration of 25 mM (3.3 g L−1) and a specific product yield of 0.4 g gCDW−1 were achieved with the higher feed rate. Product inhibition and substrate toxification were identified as critical factors limiting biocatalytic performance. Future research efforts on these factors and the precise adjustment of the cyclohexane feed combined with an in situ product removal strategy are discussed as promising strategies to enhance biocatalyst durability and product titer and thus to enable the development of a sustainable multistep whole-cell process.

Application of the polycaprolactone polymer for the encapsulation of geraniol: evaluation of the efficiency and stability

Abstract Geraniol has been an attractive compound for food preservation due to its antibacterial and antifungal actions. The main objective of this study was to produce and characterize polycaprolactone (PCL) capsules for the protection of the encapsulated geraniol essential oil. The encapsulation was carried out using a miniemulsion polymerization technique with an efficiency of (95.44 ± 0.60%). The capsules were obtained with a mean size of 148 nm and with a polydispersity index of 0.12. Transmission electron microscopy results confirmed the formation of spherical capsules of PCL coating the geraniol. From the analysis of thermogravimetry, it was possible to prove the thermal protection of geraniol by PCL coating since the release of the encapsulated geraniol occurred with temperatures 100 °C higher than the volatilization temperature of the natural compound. An important observation was that the microcapsules of PCL-geraniol immersed in aqueous suspensions at 4 °C showed good stability over 60 days.

Well-aligned Polycaprolactone Fiber by Stable Jet Electrospinning

In this work, polycaprolactone (PCL) fiber membrane with random, partially aligned and well-aligned morphology by conventional electrospinning, high speed drum electrospinning and stable jet electrospinning, respectively. By adjusting PCL polymer solution (solution viscosity and conductivity) and electrospinning parameter (voltage, temperature, humidity et al.), well-aligned PCL membrane with fibers arranged in one direction under SEM observation. The mechanical behaviour were also studied. The stable jet electrospinning offers a possibility of producing well-aligned fiber membranes for future potential applications.