Development of double porous poly (ε - caprolactone)/chitosan polymer as tissue engineering scaffold

Durable and recyclable MOF@polycaprolactone mixed-matrix membranes with hierarchical porosity for wastewater treatment

With the fast-growing global water crisis, the development of novel technologies for water remediation and reuse is crucial. Industrial wastewater especially contains various toxic pollutants that pose an additional threat to the environment; thus, efficient removal of such contaminants can ensure safe reprocessing of industrial wastewater, thereby alleviating the demand for fresh water. Herein, we describe a novel and efficient approach for preparing porous polycaprolactone (PCL) membranes with a hierarchical architecture via a simple solvent/non-solvent methodology. A mixed-matrix membrane (MMM) was further constructed utilizing an amine-functionalized metal-organic framework as the sorbent filler nanoparticles and PCL as the polymer support matrix (MOF@PCL) for wastewater treatment applications. The MOF@PCL MMM demonstrated homogeneous morphology as well as exceptional performance towards the removal of both cationic (methylene blue, MB) and anionic (methyl orange, MO) organic dyes, where the maximum adsorption capacities reached 309 mg g-1 and 208 mg g-1, respectively. Kinetic and thermodynamic investigations revealed that the adsorption process was endothermic with a fast intraparticle diffusion rate constant. The MOF@PCL MMM also displayed excellent mechanical stability and recyclability, where the removal efficiency was maintained after 10 cycles.

The polycaprolactone/silk fibroin/carbonate hydroxyapatite electrospun scaffold promotes bone reconstruction by regulating the polarization of macrophages

Macrophages are known to modulate the osteogenic environment of bone regeneration elicited by biological bone grafts. Alteration in certain chemical components tends to affect macrophages polarization. Comparatively to hydroxyapatite (HAp), carbonate hydroxyapatite (CHA) consists of 7.4 (wt%) carbonate ions and more closely resembles the mineral content of bone. It remains unknown whether CHA scaffolds or HA scaffolds have better osteogenic properties. In this study, we fabricated PCL/SF scaffold, PCL/SF/HAp scaffold and PCL/SF/CHA scaffold using the electrospinning technique. Despite comparable mechanical properties, the PCL/SF/CHA scaffold exhibited better osteogenic properties than the PCL/SF/HAp scaffold. Although no significant differences were observed between the two scaffolds for promoting osteoblast differentiation in vitro, the PCL/SF/CHA group appeared to be more effective at promoting bone regeneration in cranial defects in vivo. The PCL/SF/CHA scaffold was found to promote macrophage polarization toward M2 via activating the JAK/STAT5 pathway which caused a pro-osteogenic microenvironment to facilitate osteoblast differentiation. The results of this study indicated a higher potential of CHA to substitute HAp in the production of bone scaffolds for better bone regeneration.

PCL/Andiroba Oil (Carapa guianensis Aubl.) Hybrid Film for Wound Healing Applications

Developing a biomimetic material to wound care is an emerging need for the healing process. Poly (ε-caprolactone) (PCL) is a polymer with the necessary dressing's requirements often used in medicine. Their surface, physic-chemical and biological properties can be modified by adding bioactive compounds, such as andiroba seed oil (Carapa guianensis). This Amazonian natural plant has medicinal and pharmacological properties. For this purpose, PCL polymeric films incorporated with andiroba oil were investigated. The synthesis of hybrids materials was carried out in the solvent casting method. Thermal properties were evaluated using thermogravimetric analysis (TGA/DTGA) and differential scanning calorimetry (DSC). The solvent type on the surface and hydrophilicity of samples was studied using a scanning electron microscope (SEM). Additionally, contact angle measurements, functional groups analysis, fluid absorption capacity, and cell viability were performed. The results demonstrated the influences of andiroba oil under the morphology and thermal properties of the polymeric matrix; the hydrophilicity of the hybrid film obtained by acetic acid was reduced by 13%; the porosity decreased as the concentration of oil increased, but its higher thermal stability. The L929 cell line's proliferation was observed in all materials, and it presented nontoxic nature. It was demonstrated the ability of PCL hybrid film as a matrix for cell growth. Then, the materials were proved potential candidates for biomedical applications.

Step-by-step design of poly (ε-caprolactone) /chitosan/Melilotus officinalis extract electrospun nanofibers for wound dressing applications

Composition of polymers and choosing the type of solvents in electrospinning systems is of great importance to achieve a mat with optimal properties. In this work, with emphasizing the influence of a novel solvent system, an electrospun wound dressing was designed in four steps. Firstly, to study the effect of polymer-solvent interactions and electrospinning distance, a constant amount of polycaprolactone (PCL) was dissolved at different compositions of formic acid (FA)/dichloromethane (DCM) and was electrospun at different distances. The composition of 80FA/20DCM and distance of 15 cm were selected as optimal conditions by lowest average diameter of fibers and simultaneously good surface uniformity. In the second step, the concentration of PCL was considered variable to achieve the lowest diameter of fibers. Finally, in the third and fourth steps, different concentrations of chitosan (CN) and constant dosage of Melilotus officinalis (MO) extract were added to the solution. The extract contained fibers had a mean diameter of 275 ± 41 nm which is in the required condition for wound caring. Eventually, the optimized PCL/CN and PCL/CN/MO specimens were evaluated by FTIR, DSC, Tensile, water contact angle, antibacterial assays, cell viability, and drug release analysis for determining their function and properties.

Chitosan based-nanoparticles and nanocapsules: Overview, physicochemical features, applications of a nanofibrous scaffold, and bioprinting

Recent advancements in the synthesis, properties, and applications of chitosan as the second after cellulose available biopolymer in nature were discussed in this review. A general overview of processing and production procedures from A to Z was highlighted. Chitosan exists in three polymorphic forms which differ in degree of crystallinity (α, β, and γ). Thus, the degree of deacetylation, crystallinity, surface area, and molecular mass significantly affect most applications. Otherwise, the synthesis of chitosan nanofibers is suffering from many drawbacks that were recently treated by co-electrospun with other polymers such as polyvinyl alcohol (PVA), polyethylene oxide (PEO), and polycaprolactone (PCL). Ultimately, this review focuses on the area of new trend utilization of chitosan nanoparticles as nanospheres and nanocapsules, in cartilage and bone regenerative medicine. Owing to its biocompatibility, bioavailability, biodegradability, and costless synthesis, chitosan is a promising biopolymeric structure for water remediation, drug delivery, antimicrobials, and tissue engineering.

Self-assembly of dextran - b - deoxycholic acid polyester copolymers: Copolymer composition and self-assembly procedure tune the aggregate size and morphology

Self-assembly potential of new amphiphilic block copolymers containing dextran (M_n 4500, 8000, 15,000) and a semi-rigid deoxycholic acid-oligoethyleneglycol polyester (M_n 2500-8800, 2 or 4 ethyleneglycol units), was evaluated as a function of copolymer composition and self-assembly procedure, using dynamic light scattering and transmission electron microscopy. Addition of copolymer solution to water provided small star-like micelles (∼ 100 nm), while addition of water to copolymer solution led to various morphologies and sizes (60-600 nm), depending on polymer composition. Worm-like micelles were obtained from a copolymer containing dextran with M_n 4500 and 66 wt% polyester, and vesicles were formed by copolymers prepared from dextran with M_n 8000 and containing 46 wt% polyester. Presence of a longer oligoethyleneglycol decreased the size of micelles and vesicles due to an enhanced flexibility of the polyester hydrophobic block. The results allow the selection of the most appropriate parameters to obtain the desired aggregate characteristics.

Three-Dimensional Printing Constructs Based on the Chitosan for Tissue Regeneration: State of the Art, Developing Directions and Prospect Trends

Chitosan (CS) has gained particular attention in biomedical applications due to its biocompatibility, antibacterial feature, and biodegradability. Hence, many studies have focused on the manufacturing of CS films, scaffolds, particulate, and inks via different production methods. Nowadays, with the possibility of the precise adjustment of porosity size and shape, fiber size, suitable interconnectivity of pores, and creation of patient-specific constructs, 3D printing has overcome the limitations of many traditional manufacturing methods. Therefore, the fabrication of 3D printed CS scaffolds can lead to promising advances in tissue engineering and regenerative medicine. A review of additive manufacturing types, CS-based printed constructs, their usages as biomaterials, advantages, and drawbacks can open doors to optimize CS-based constructions for biomedical applications. The latest technological issues and upcoming capabilities of 3D printing with CS-based biopolymers for different applications are also discussed. This review article will act as a roadmap aiming to investigate chitosan as a new feedstock concerning various 3D printing approaches which may be employed in biomedical fields. In fact, the combination of 3D printing and CS-based biopolymers is extremely appealing particularly with regard to certain clinical purposes. Complications of 3D printing coupled with the challenges associated with materials should be recognized to help make this method feasible for wider clinical requirements. This strategy is currently gaining substantial attention in terms of several industrial biomedical products. In this review, the key 3D printing approaches along with revealing historical background are initially presented, and ultimately, the applications of different 3D printing techniques for fabricating chitosan constructs will be discussed. The recognition of essential complications and technical problems related to numerous 3D printing techniques and CS-based biopolymer choices according to clinical requirements is crucial. A comprehensive investigation will be required to encounter those challenges and to completely understand the possibilities of 3D printing in the foreseeable future.