Polycaprolactone Films Research Articles

“Janus” PEEK implant with sandwich Mg-containing coating for infected tissue repair

Having good antibacterial properties and promoting soft and hard tissue repair are the keys to successful implantation of intraosseous transcutaneous. Polyether ether ketone (PEEK) is a class of FDA-approved polymer implants. However, the surface of PEEK is bioinert, which is easy to cause postoperative infection and poor tissue integration. In this study, polypyrrole (Ppy) was polymerized on sulfonated PEEK, Mg3(PO4)2 nanosheets were grown in situ on one side, and polycaprolactone (PCL) was then spun on the surface to form a Janus-like surface on PEEK. The Ppy/Mg3(PO4)2/PCL composite coating could inhibit bacterial adhesion, and the excellent photothermal properties of Ppy/Mg3(PO4)2/PCL and Ppy coatings further promote the removal of bacteria due to the accumulated heat. After the infection was eliminated, the Janus-like surface of modified PEEK switched macrophages to anti-proinflammatory response and promoted both soft and hard tissue repair. The Ppy modified sulfonated PEEK could promote collagen secretion in the soft tissue, while the PCL films on Ppy/Mg3(PO4)2/PCL was densified by temperature response under near-infrared light treatment to close the exposed interface of Mg3(PO4)2 nanosheets that was more conducive to bone repair. In summary, PEEK with Janus-like surface consisting of Ppy/Mg3(PO4)2/PCL and Ppy has multiple biological functions of sequential antibacterial and soft and hard tissue repair, and is a promising candidate material for intraosseous transcutaneous implants.

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

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

Polycaprolactone-based electrospun films incorporating sage extract: From active food packaging application to accelerated biodegradation by Pseudomonas

Polycaprolactone films incorporating sage extract (SE), developed by electrospinning and annealing, were tested as active, fast-degradable food contact materials. First, a release test with food simulants showed the films’ ability to release phenolics. This beneficial property was highlighted in the films’ application as pads for preventing raspberry quality deterioration. The highest SE containing film (20 %) demonstrated the highest preserving potential, suppressing raspberry spoilage, breakdown of soluble solids, maintaining color, and increasing phenolics content. Secondly, the degradation under natural environment conditions and conditions accelerating the degradation of the films was evaluated. Complete films’ bio-disintegration in compost occurred within three months, being catalyzed to four weeks by adding Pseudomonas aeruginosa, regardless of the SE incorporation. Visual appearance, light, scanning electron, and atomic force microscopy indicated an inhomogeneous surface degradation mechanism depended on the morphology of the films. Analysis of the structural properties and crystallinity showed that both amorphous and crystalline film regions were affected by biodegradation. The developed films as packaging materials can be beneficial from an economic and environmental point of view, as they can extend the shelf-life of fresh fruit, prevent the generation of food waste, reduce the accumulation of discarded packaging materials, protect the environment, and contribute to sustainable development.

Enhancement of the chondrogenic differentiation capacity of human dental pulp stem cells via chondroitin sulfate-coated polycaprolactone-MWCNT nanofibers

Most of the conditions involving cartilaginous tissues are irreversible and involve degenerative processes. The aim of the present study was to fabricate a biocompatible fibrous and film scaffolds using electrospinning and casting techniques to induce chondrogenic differentiation for possible application in cartilaginous tissue regeneration. Polycaprolactone (PCL) electrospun nanofibrous scaffolds and PCL film were fabricated and incorporated with multi-walled carbon nanotubes (MWCNTs). Thereafter, coating of chondroitin sulfate (CS) on the fibrous and film structures was applied to promote chondrogenic differentiation of human dental pulp stem cells (hDPSCs). First, the morphology, hydrophilicity and mechanical properties of the scaffolds were characterized by scanning electron microscopy (SEM), spectroscopic characterization, water contact angle measurements and tensile strength testing. Subsequently, the effects of the fabricated scaffolds on stimulating the proliferation of human dental pulp stem cells (hDPSCs) and inducing their chondrogenic differentiation were evaluated via electron microscopy, flow cytometry and RT‒PCR. The results of the study demonstrated that the different forms of the fabricated PCL-MWCNTs scaffolds analyzed demonstrated biocompatibility. The nanofilm structures demonstrated a higher rate of cellular proliferation, while the nanofibrous architecture of the scaffolds supported the cellular attachment and differentiation capacity of hDPSCs and was further enhanced with CS addition. In conclusion, the results of the present investigation highlighted the significance of this combination of parameters on the viability, proliferation and chondrogenic differentiation capacity of hDPSCs seeded on PCL-MWCNT scaffolds. This approach may be applied when designing PCL-based scaffolds for future cell-based therapeutic approaches developed for chondrogenic diseases.

Development of Drug-Loaded PCL@MOF Film Enclosed in a Photo Polymeric Container for Sustained Release.

The programmed fabrication of oral dosage forms is associated with several challenges such as controlled loading and disintegration. To optimize the drug payload, excipient breakdown, and site-specific sustained release of hydrophobic drug (sulfamethoxazole, SM), we propose the development of acrylate polymer tablets enclosed with drug-loaded polycaprolactone (PCL) films. The active pharmaceutical ingredient (API) is physisorbed into the porous iron (Fe)-based metal-organic framework (MOF) and later converted to tangible PCL films, which, upon folding, are incorporated into the acrylate polymer matrices (P1/P2/P3). X-ray powder diffraction (XRPD) analysis and scanning electron microscopy (SEM) micrographs confirmed the stability and homogeneous distribution of MOF within the 50 μm thick film. Adsorption-desorption measurements at ambient temperatures confirmed the decrease in the BET surface area of PCL films by 40%, which was ∼3.01 m/g, and pore volume from 30 to 9 nm. The decrease in adsorption and surface parameters could confirm the gradual accessibility of SM molecules once exposed to a degrading environment. Fourier transform infrared (FTIR) analyses of in vitro dissolution confirmed the presence of the drug in the MOF-PCL film-enclosed tablets and concluded the cumulative SM release at pH ∼ 8.2 which followed the order SM@Fe-MOF < P1/P2/P3 < PCL-SM@Fe-MOF < P1/PCL-SM@Fe-MOF < P3/PCL-SM@Fe-MOF. The results of the study indicate that the P3/PCL-SM@Fe-MOF assembly has potential use as a biomedical drug delivery alternative carrier for effective drug loading and stimuli-responsive flexible release to attain high bioavailability.

Biodegradable monolayer film based on the collagen extracted from Oreochromis sp. processing byproducts blended with chitosan and assembled with PCL and PLA monolayers to form bilayers films

AbstractThe objective of the study is to develop and characterize biodegradable monolayer and bilayer films using collagen extracted from tilapia skin and scales (Oreochromis sp.) with chitosan in combination with biodegradable polyester; polylactic acid (PLA) or polycaprolactone (PCL). Collagen extraction was conducted with acetic acid (0.5 M). Monolayer films based on collagen and chitosan were formed by the casting process with a solution of chitosan (2% w/w) in 1.5% acetic acid, followed by the addition of skin collagen at concentrations of 0.5%, 1%, or 2% w/w, and dried at 45–50°C. The PLA and PCL films were made by compression molding. The films were characterized according to their appearance, structure, morphology, interaction with water, thermal stability, and mechanical and barrier properties. The results indicated that collagen from tilapia skin and scales yielded 36.5% and 2.57%, respectively. The results showed that adding chitosan increased the tensile strength but decreased the elongation of the films. An improvement in thermal stability was observed by increasing the proportion of collagen or chitosan, and it also influenced water solubility and water vapor permeability. Microscopy showed a crack‐free interface between collagen and chitosan. The color of the films varied depending on the composition, highlighting the influence of chitosan in yellow and reddish tones. The bilayers with PLA had lower water vapor permeability and higher gloss compared to those with PCL. Finally, the developed films showed promising properties for their application in food packaging and promote the use of fishery waste.Practical applicationsThe study aims to develop and characterize biodegradable monolayer and bilayer films using collagen extracted from tilapia skin and scales (Oreochromis sp.) combined with chitosan and biodegradable polyester such as polylactic acid or polycaprolactone. The practical applications of this research span a wide range of industrial fields. For instance, monolayer films could be used as sustainable food packaging, offering enhanced barrier properties and biodegradability, thus reducing the environmental impact of conventional packaging. Furthermore, bilayer films could find applications in the healthcare industry, such as controlled‐release drug patches or dressings leveraging the antimicrobial properties of chitosan. This research also provides valuable insights into improving the mechanical, thermal, and barrier properties of biodegradable films, potentially leading to the production of more efficient and versatile materials for a variety of industrial applications.

A novel polycaprolactone film-coated electrode incorporating aluminum nanoparticles for pyruvate biosensing in clinical diagnosis

Pyruvate is an important parameter that is measured in a wide range of fields, from healthcare to environmental monitoring. Accurate and rapid measurement of pyruvate is therefore essential. Biosensors are well suited for this purpose. A novel, simple, and reliable biosensor was developed by modifying a polycaprolactone film with aluminum nanoparticles and used for the first time to detect pyruvate. The electrochemical properties and surface characteristics of the aluminum nanoparticle-modified film-coated gold electrode were investigated using cyclic voltammetry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The biosensor responded to pyruvate within a concentration range of 1 μM to 1000 μM with a sensitivity of 2.30 µA µM−1 cm−2 at an applied potential of + 0.4 V. The obtained accuracy was 99.5 % ± 0.002 with a relative standard deviation of only 0.041 %. The limit of detection was calculated to be 0.45 μM. The accuracy of spiked pyruvate measurement in a complex medium was highly accurate, with a result of 105.11 ± 0.02 % when tested using human serum from male AB plasma. The initial response was maintained at 98 % and 87 % after 10 and 20 days, respectively.

Sodium alginate-based multifunctional sandwich-like system for treating wound infections

Microbial colonization and development of infections in wounds is a sign of chronicity. The prevailing approach to manage and treat these wounds involves dressings. However, these often fail in effectively addressing infections, as they struggle to both absorb exudates and maintain optimal local moisture. The system here presented was conceptualized with a three-layer design: the outer layer made of a fibrous polycaprolactone (PCL) film, to act as a barrier for preventing microorganisms and impurities from reaching the wound; the intermediate layer formed of a sodium alginate (SA) hydrogel loaded with ampicillin (Amp) for fighting infections; and the inner layer comprised of a fibrous film of PCL and polyethylene glycol (PEG) for facilitating cell recognition and preventing wound adhesion. Thermal evaluations, degradation, wettability and release behavior testing confirmed the system resistance overtime. The sandwich demonstrated the capability for absorbing exudates (≈70 %) and exhibited a controlled release of Amp for up to 24 h. Antimicrobial testing was performed against Staphylococcus aureus and Escherichia coli, as representatives of Gram-positive and Gram-negative bacteria: >99 % elimination of bacteria. Cell cytotoxicity assessments showed high cytocompatibility levels, confirming the safety of the proposed sandwich system. Adhesion assays confirmed the system ease of detaching without mechanical effort (0.37 N). Data established the efficiency of the sandwich-like system, suggesting promising applications in infected wound care.

Platelet-Rich Plasma-Embedded Porous Polycaprolactone Film with a Large Surface Area for Effective Hemostasis.

Uncontrollable and widespread bleeding caused by surgery or sudden accidents can lead to death if not treated with appropriate hemostasis. To prevent excessive life-threatening bleeding, various hemostatic agents based on polymeric biomaterials with various additives for accelerated blood coagulation have been adopted in clinical fields. In particular, platelet-rich plasma (PRP), which contains many blood coagulation factors that can accelerate blood clot formation, is considered as one of the most effective hemostatic additives. We investigated a PRP-embedded porous film using discarded (expired) PRP and a film with a leaf-stacked structure (FLSS), as a hemostatic agent to induce rapid hemostasis. The film, which contained an LSS on one side (PCL-FLSS), was fabricated by a simple heating-cooling technique using tetraglycol and polycaprolactone (PCL) film. Activated PRP was obtained by the thawing of frozen PRP at the end of its expiration date (the platelet cell membrane is disrupted during the freezing and thawing of PRP, thus releasing various coagulation factors) and embedded in the PCL-FLSS (PRP-FLSS). From in vitro and in vivo experiments using a rat hepatic bleeding model, it was recognized that PRP-FLSS is not only biocompatible but also significantly accelerates blood clotting and thus prevents rapid bleeding, probably due to a synergistic effect of the sufficient supply of various blood coagulants from activated PRP embedded in the LSS layer and the large surface area of the LSS itself. The study suggests that PRP-FLSS, a combination of a porous polymer matrix with a unique morphology and discarded biofunctional resources, can be an advanced hemostatic agent as well as an upcycling platform to avoid the waste of biofunctional resources.

Electroanalytical analysis of phenol oxidation using bacteria immobilized by a polycaprolactone coating on the copper electrode surface

The copper electrode modified by bacteria immobilised by a polycaprolactone film was successfully developed by electropolymerisation for the purpose of determining the presence of phenol. Electrochemical techniques such as square-wave voltammetry (SWV), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrochemical properties of the Cu-polymer/bacteria electrode. The results show that the intensity of the phenol oxidation peak increases with concentration, allowing us to obtain good analytical results with DL of 2.156 × 10–7 M and QL which is 7.2 × 10–7 M , confirming that the biosensor has excellent electroanalytical activity for phenol oxidation, with good stability and a wide linear range. Our electrode is based on a easily available and inexpensive material, as well as on its simple preparation, which has demonstrated high performance for phenol.

Polycaprolactone (PCL)-based films integrated with hairy cellulose nanocrystals and silver nanoparticles for active Tilapia packaging applications

The migration of metal ions to the food matrix has been always a challenge in the production of active food packaging films. In this study, it was tried to evaluate the idea of using hairy cellulose nanocrystals (HCNs) in controlling the migration of Silver Nanoparticles (AgNPs) from polycaprolactone (PCL)-based films to the Tilapia fish. HCNs and the final films (integrated with various amounts of HCNs and AgNPs) were evaluated physicochemically and mechanically. Tilapia fish were packed using the films and after specific periods, the fish samples were assessed microbiologically and physiochemically. According to the results, incorporating NPs into PCL films enhanced tensile strength, elasticity, and toughness making the films more resistant to breakage and deformation under stress. The introduction of HCNs reduced the surface roughness level, decreasing AgNPs migration, but also accelerated the degradation rate. Films with [1% AgNPs +2% HCNs] and [1% AgNPs] had the lowest and highest water vapor transmission rate. The use of AgNPs (1%) + HCNs (2%) incorporated into PCL films resulted in a lower pH value, TVB-N, TBARs, and PV. It also decreased microbial activities in samples in comparison to the control. Therefore, the idea of using HCNs along with antibacterial metal-based nanoparticles can control the rate of ion migration.

Nanocomposite films of polycaprolactone and amorphous/sintered wollastonite nanoparticles for potential biomedical applications

Precipitation of an apatite layer on the surface of bioactive materials is considered an important step in the bone healing procedure. Wollastonite (CaSiO3) bioglass has been recently employed as a bone replacement material and also, a carrier for targeted drug delivery. Regarding the impact of a material structure on its biological activity, to achieve the 100 % clinical success, realizing the material crystallinity and bone bonding potential can be important. Therefore, this study tried to prepare pure wollastonite (WS) nano-powders (<20 nm) via an easy and fast hydrothermal process. Different quantities (5, 10 and 15 wt%) of the amorphous and crystalline particles have been added to polycaprolactone (PCL) to obtain composite films via a simple solvent casting technique. The in-vitro bioactivity of the prepared particles as well as composite films was studied by placing the samples in the simulated body fluid (SBF) for 21 days. The physicochemical and microstructural properties of the products were then characterized by XRD, FTIR, FESEM, EDS and TEM. Moreover, the influence of the crystallinity on the bioactivity of the synthesized nanoparticles and also the obtained composite films was investigated for the first time. The results indicated that the amorphous bioglass and the surface of composite containing 15 wt% WS were completely covered by a thick bone-like apatite layer Therefore, these findings revealed that the prepared composite films composed of amorphous WS could be regarded as promising bioactive candidates for bone filling applications.

Comprehensive study of antimicrobial polycaprolactone/clay nanocomposite films: Preparation, characterization, properties and degradation in simulated body fluid

AbstractEven though the biodegradability of polycaprolactone (PCL) and its nanocomposites is lower compared to other biodegradable polyesters, this property and good biocompatibility are used for development of materials for drug delivery with a long‐term effect. We prepared novel PCL/clay nanocomposite films with antimicrobials chlorhexidine (CH) or octenidine (OCT) combined with ZnO anchored on vermiculite (VER). The intercalation of CH and OCT into the interlayer of VER/ZnOVER was confirmed by XRD, FTIR and SEM. The organically modified nanofillers compared to VER (−46.0 mV) or ZnOVER (−34.9 mV) showed a positive ζ‐potential (+30.7 mV (VER_CH), +21.9 mV (VER_OCT), +24.6 mV (ZnOVER_CH)) indicating a relatively stable materials, except ZnOVER_OCT (+8.6 mV), which strongly agglomerated.Thin PCL/clay films were prepared by solvent casting method and the effect of used nanofillers on structural, thermal, mechanical and antimicrobial properties followed by degradation under hydrolytic conditions was studied. The results showed that presence of ZnO significantly decreases thermal and mechanical stability. The nanofillers with the higher hydrophilic character are responsible for the fastest degradation of PCL matrix. Films possessed high antimicrobial efficiency in long time intervals, hence these nanocomposites open new avenues for the possible application of such materials for the drug delivery with a long‐term effect.Highlights Antimicrobial active PCL/clay nanocomposites were prepared. Nanofillers influenced the structure and properties of prepared thin PCL films. ZnO caused lower thermal stability and worse mechanical properties of PCL films. PCL/clay nanocomposite films degraded slowly by a hydrolytic mechanism. High potential as medical materials with long‐lasting antimicrobial efficacy.

Pectin wrapped halloysite nanotube reinforced Polycaprolactone films for potential wound healing application

The current research work focuses on preparing the polycaprolactone (PCL) based nanocomposite films embedded with surface modified Halloysite Nanotube (HNT). The avenue of the study is to unravel the applicability of polymer nanocomposites for wound healing. The flexible property of HNT was taken as the major force to accomplish the addition of biopolymer pectin onto its surface. Functionalization of HNT with pectin has certainly enhanced its binding nature with the polymer. The PCL nanocomposite films were characterized by several promising techniques such as FTIR, XRD, DSC-TGA, FESEM, TEM, AFM, and mechanical properties were too examined along. When compared to the plane PCL film, the nanocomposite films manifested favorable results in terms of mechanical and chemical properties. Additionally, biometric studies such as in-vitro swelling, enzymatic degradation, and hemolysis performed on the films gave extremely good results. The haemolytic percentage recorded for the films exhibited a steady decrease with increasing amount of nanofillers. The MTT assay showed cell proliferation and its increase as the embedded HNT is more in the matrix. Wound closure study performed on NIH3T3 cell line with 1, 3 and 5wt% of films has given a strong proof for the involvement of polymer and HNT in the healing procedure.

Novel Nano Biodegradable Package Films of Polycaprolactone / Extracted Gelatin from White Shavings

Novel Nano Biodegradable Package Films of Polycaprolactone / Extracted Gelatin from White Shavings

Biodegradable UV-Protective Composite Film from Cellulosic Waste: Utilisation of Cotton Gin Motes as Biocomponent.

With an increase in environmental pollution and microplastic problems, it is more urgent now to replace non-biodegradable films with biodegradable films that are low-cost and from renewable resources. Cotton gin motes (GM), a type of cellulosic waste that is generated from cotton ginning, is an excellent candidate for fabricating biodegradable films due to its properties and abundance. In this study, GM was first mechanically milled into a fine powder, followed by compounding with polycaprolactone (PCL) and extruded to produce composite pellets which were then compress-moulded into composite films. This environmentally friendly process used physical processing and all the materials were consumed in the process without generating any waste residue. To improve the compatibility and mixing properties between GM and PCL, the use of a plasticiser (polyethylene glycol) was considered. A high content of GM powder (up to 50%) was successfully compounded with the polymer. The SEM images of the composite films showed smooth surface morphology and well-distributed GM powder in the PCL matrix. The added advantage of compounding GM with the polymer matrix was that the composite film developed UV-shielding properties due to the presence of lignin in the GM powder. This property will be critical for films used in UV-resistance applications. Furthermore, the composite even with high GM content (50%), showed good mechanical properties, with 9.5 MPa yield strength and 442% elongation, which was only a 50% decrease in elongation when compared with clear PCL film. The soil biodegradation of GM composite films under controlled temperature (20 °C) and humidity (50%) for 1 month showed around 41% weight loss. Overall, this study demonstrates the potential of GM to be used as a biodegradable and UV-protective composite film for a wide array of applications, such as packaging and UV-protective coverings.

Improvement of Endothelial Cell-Polycaprolactone Interaction through Surface Modification via Aminolysis, Hydrolysis, and a Combined Approach

Polycaprolactone (PCL) is a promising material for the fabrication of alternatives to autologous grafts used in coronary bypass surgery. PCL biodegrades over time, allowing cells to infiltrate the polymeric matrix, replacing the biodegrading graft, and creating a fully functional vessel constituted of autologous tissue. However, the high hydrophobicity of PCL is associated with poor cell affinity. Surface modification of PCL can increase this cell affinity, making PCL an improved scaffold material for acellular vascular grafts. In this study, the surface of PCL films was modified by hydrolysis, aminolysis, and the combination thereof to introduce carboxyl, hydroxyl, and amino groups on the surface. Only the hydrolyzed films exhibited a significant increase in their hydrophilicity, although further testing showed that all aminolysis conditions had amino groups on the surface. Furthermore, in vitro experiments with human umbilical endothelial cells (HUVECs) were performed to assess changes in cell affinity for PCL due to the surface treatments. PCL treated with sodium hydroxide (NaOH), a hydrolysis reaction, showed a significant increase in endothelial cell adhesion after 24 hours with a significant increase in cell survival after 72 hours. Thus, NaOH treatment improves the biocompatibility and endothelialization of PCL, creating a competent candidate for artificial, acellular, biodegradable vascular grafts.

Influence of polymer solution composition on the microstructure and thermal and mechanical characteristics of polycaprolactone films

AbstractThis study investigates the effects of addition of oils and alkanes to the polymer solution on the properties of polycaprolactone (PCL) films. The films were prepared by casting films onto a mold and evaporation in air. Films made without oils showed a dense microstructure. Most of the oils generated porous films, except for cyclohexane and castor oil. The neat PCL and cyclohexane films were stronger than other films, with a tensile strength of about ~11.5 MPa, followed by terpenes (~6.5 MPa) and the weakest films were obtained with hexadecane (~3.5 MPa). The elastic modulus was highest with limonene (~350 MPa), followed by cyclohexane (~150 MPa), and the lowest modulus (~65 MPa) was obtained with castor oil and hexadecane. All films showed high elongation at break (&gt;400%). The degree of crystallinity was the highest with terpenes, whereas the lowest crystallinity was obtained with hexadecane. No significant effect of the oils on the thermal transition temperatures of the films could be observed. In summary, the microstructure and mechanical properties of the PCL films could be effectively fine‐tuned for various applications through the addition of oils and alkanes to the polymer solution.Highlights Oils and alkanes were added to polycaprolactone (PCL) casting solution. PCL films were prepared by casting films onto a mold and evaporation in air. Oils affected the microstructure and mechanical properties of the films. Addition of oils provides a flexible tool to tailor the film properties. PCL films with varying properties could be fabricated for different fields.

Engineered Geobacillus lipolytic enzymes – Attractive polyesterases that degrade polycaprolactones and simultaneously produce esters

Plastic pollution is one of the biggest environmental problems plaguing the modern world. Polyester-based plastics contribute significantly to this ecological safety concern. In this study, lipolytic biocatalysts GD-95RM and GDEst-lip developed based on lipase/esterase produced by Geobacillus sp. 95 strain were applied for the degradation of polycaprolactone films (Mn 45.000 (PCL45000) and Mn 80.000 (PCL80000)). The degradation efficiency was significantly enhanced by the addition of short chain alcohols. Lipase GD-95RM (1 mg) can depolymerize 264.0 mg and 280.7 mg of PCL45000 and PCL80000, films respectively, in a 24 h period at 30 °C, while the fused enzyme GDEst-lip (1 mg) is capable of degrading 145.5 mg PCL45000 and 134.0 mg of PCL80000 films in 24 h. The addition of ethanol (25 %) improves the degradation efficiency ~2.5 fold in the case of GD-95RM. In the case of GDEst-lip, 50 % methanol was found to be the optimal alcohol solution and the degradation efficiency was increased by ~3.25 times. The addition of alcohols not only increased degradation speeds but also allowed for simultaneous synthesis of industrially valuable 6-hydroxyhexonic acid esters. The suggested system is an attractive approach for removing of plastic waste and supports the principles of bioeconomics.

The green synthesis of carbon quantum dots (CQDs) and characterization of polycaprolactone (PCL/CQDs) films

The synthesis of photoluminescent carbon quantum dots (CQD) from natural products is one of the most remarkable types of carbon-based nanomaterials due to their small size, high water solubility, nontoxicity, high stability, and excellent biocompatibility. New RC-CQDs have been prepared from natural material (rosehip fruit) via a hydrothermal method. CA-CQDs samples were synthesized from a synthetic carbon source (citric acid) by the same method for comparison with RC-CQDs. The maximum quantum yields of the as-prepared RC-CQDs and CA-CQDs samples were 23.8% and 9.6%, respectively. High-resolution transmission electron microscopy (RTEM) of RC-CQDs revealed a sphere shape with an approximate size of 5 nm, CA-CQDs were greater than 5 nm. Biodegradable polycaprolactone (PCL), which is used in bioengineering applications thanks to its mechanical and biodegradable properties, was used as a polymer matrix in this study. The PCL/RC-CQDs and PCL/CA-CQDs nanocomposite films were produced via liquid phase ultrasonic mixing at different amounts of RC-CQDs and CA-CQDs in PCL matrix (0.3-; 0.5-; 1.2-; 2.0% and 4.0% by weight), while unfilled PCL was also produced for comparison. The structural, mechanical, and biodegradable behaviors of PCL/RC-CQDs nanocomposite films have been investigated to improve the mechanical properties of PCL and increase its potential usability in load-bearing applications. PCL/RC-CQDs-2.0 film gave the maximum tensile strength value (17.65 MPa) with an increment of 27.7% and the highest value of the yield strength 9.02 MPa (an increase of 40.9%) and the highest value of microhardness 4.80 HV0,025 (an increase of 14.8%) were obtained using PCL/RC-CQDs-4.0 film compared with the PCL. The tensile strength and % elongation at break values of the PCL/CA-CQDs-0.3 film decreased by 14.8% and 133.1% compared with the PCL, respectively. The microhardness of the PCL/CA-CQDs-0.3 film was 5.48 HV0,025, increasing by 31.1% in comparison with 4.18 HV0,025, for the PCL. Biodegradability test results showed that films containing RC-CQDs exhibited lower weight loss than the PCL and films containing CA-CQDs. This result was attributed to the amorphous structure, low surface roughness and high contact angle of the RC-CQDs containing films. And also, CA-CQDs made PCL films more hydrophilic according to low contact angle results.