Curcumin incorporated polyurethane urea elastomers with tunable thermo-mechanical properties

Gum arabic as a sole wall material for constructing nanoparticle to enhance the stability and bioavailability of curcumin

In this study, a kind of nanoparticle prepared using gum arabic as a sole wall material for loading curcumin was obtained. The properties and digestive characteristics of the curcumin-loaded nanoparticle were determined. Results showed that the maximum loading amount of the nanoparticle was 0.51 µg/mg with an approximately 500 nm size. The Fourier transform infrared (FTIR) spectrum showed that the complexation was mainly related to the -C[bond, double bond]O, -CH, and -C-O-C- groups. The curcumin-loaded nanoparticle exhibited good stability under highly concentrated salinity stress, and the stability of the curcumin loaded in nanoparticles was significantly higher than that of free curcumin under ultraviolet radiation. The curcumin loaded in nanoparticle was released mainly in the intestinal digestion stage, and the release process was sensitive to the pH changes rather than protease. In conclusion, these nanoparticles can be a potential nanocarrier for enhancing the stability of curcumin which can be applied in the salt-containing food system.

Biocompatibility and Hemolytic Activity Studies of Synthesized Alginate-Based Polyurethanes

Many investigators have focused on the development of biocompatible polyurethanes by chemical reaction of functional groups contained in a spacer and introduced in the PU backbone or by a grafting method on graft polymerization of functional groups. In this study, alginate-based polyurethane (PU) composites were synthesized via step-growth polymerization by the reaction of hydroxyl-terminated polybutadiene (HTPB) and hexamethylene diisocyanate (HMDI). The polymer chains were further extended with blends of 1,4-butanediol (1,4-BDO) and alginate (ALG) with different mole ratios. The structures of the prepared PU samples were elucidated with FTIR and 1H NMR spectroscopy. The crystallinity of the prepared samples was evaluated with the help of X-ray diffraction (XRD). The XRD results reveal that the crystallinity of the PU samples increases when the concentration of alginate increases. Thermogravimetric (TGA) results show that samples containing a higher amount of alginate possess higher thermal stability. ALG-based PU composite samples show more biocompatibility and less hemolytic activity. Mechanical properties, contact angle, and water absorption (%) were also greatly affected.

Concerning Synthesis of New Biobased Polycarbonates with Curcumin in Replacement of Bisphenol A and Recycled Diphenyl Carbonate as Example of Circular Economy

Curcumin (CM) is a natural polyphenol well-known for its antioxidant and pharmaceutical properties, that can represent a renewable alternative to bisphenol A (BPA) for the synthesis of bio-based polycarbonates (PC). In the presented strategy, preparation of the CM-based PC was coupled with chemical recycling of the fossil-based BPA polycarbonate (BPA-PC) conducting a two-steps trans-polymerization that replaces BPA monomer with CM or its tetrahydrogenated colorless product (THCM). In the first step of synthetic strategy, depolymerization of commercial BPA-PC was carried out with phenol as nucleophile, according to our previous procedure based on zinc derivatives and ionic liquids as catalysts, thus producing quantitatively diphenyl carbonate (DPC) e BPA. In the second step, DPC underwent a melt transesterification with CM or THCM monomers affording the corresponding bio-based polycarbonates, CM-PC and THCM-PC, respectively. THCM was prepared by reducing natural bis-phenol with cyclohexene as a hydrogen donor and characterized by ¹H-NMR and MS techniques. Polymerization reactions were monitored by infrared spectroscopy and average molecular weights and dispersity of the two biobased polymers THCM-PC and CM-PC were determined by means of gel permeation chromatography (GPC). Optical properties of the prepared polymers were also measured.

Polymer-Based Materials Loaded with Curcumin for Wound Healing Applications

Some of the currently used wound dressings have interesting features such as excellent porosity, good water-absorbing capacity, moderate water vapor transmission rate, high drug loading efficiency, and good capability to provide a moist environment, but they are limited in terms of antimicrobial properties. Their inability to protect the wound from microbial invasion results in wound exposure to microbial infections, resulting in a delayed wound healing process. Furthermore, some wound dressings are loaded with synthetic antibiotics that can cause adverse side effects on the patients. Natural-based compounds exhibit unique features such as good biocompatibility, reduced toxicity, etc. Curcumin, one such natural-based compound, has demonstrated several biological activities such as anticancer, antibacterial and antioxidant properties. Its good antibacterial and antioxidant activity make it beneficial for the treatment of wounds. Several researchers have developed different types of polymer-based wound dressings which were loaded with curcumin. These wound dressings displayed excellent features such as good biocompatibility, induction of skin regeneration, accelerated wound healing processes and excellent antioxidant and antibacterial activity. This review will be focused on the in vitro and in vivo therapeutic outcomes of wound dressings loaded with curcumin.

Curcumin Incorporated Poly(Butylene Adipate-co-Terephthalate) Film with Improved Water Vapor Barrier and Antioxidant Properties

Curcumin incorporated poly(butylene adipate-co-terephthalate) (PBAT) based film was fabricated. Curcumin has uniformly distributed in the PBAT matrix to form a bright yellow PBAT/curcumin film. The PBAT/curcumin film has slightly reduced tensile strength and flexibility than the neat PBAT film, while the thermal stability of the film has not changed significantly. The blending of curcumin significantly decreased the water vapor permeability of the PBAT film. Additionally, the PBAT/curcumin film showed potent antioxidant activity with some antimicrobial activity. The PBAT/curcumin films with improved water vapor barrier and additional functions can be used for active packaging applications.

Hydrophobin-enhanced stability, dispersions and release of curcumin nanoparticles in water

Most chemotherapeutic drugs commonly suffer from low aqueous solubility that can potentially limit drugs absorption. Drug nanomerization is an advanced approach to overcoming their poor water-solubility. In this study, class I hydrophobin recombinant HGFI (rHGFI)-based curcumin (Cur) nanoparticles (rHGFI-Cur) were prepared by freeze-drying method. The rHGFI-Cur nanocomposites were characterized by contact angle, transmission electron microscopy, fluorescence microscopy and dynamic light scattering. The results showed that rHGFI could lead to the wettability conversion and stability improved of Cur in water. X-ray photoelectron spectroscopy and Fourier transform infrared suggested that rHGFI could non-covalently bind to Cur to render them hydrophilic through hydrophobic forces. Additionally, drug release and cytotoxicity assays illustrated that rHGFI-Cur nanoparticles could facilitate Cur release and exhibited higher cytotoxicity than free Cur for human esophageal cancer cells TE-1. Thus, it suggested that rHGFI has a great potential application for hydrophobic drug delivery without toxicity.[Formula: see text].

Biocompatible Aloe vera and Tetracycline Hydrochloride Loaded Hybrid Nanofibrous Scaffolds for Skin Tissue Engineering

Aloe vera (AV) and tetracycline hydrochloride (TCH) exhibit significant properties such as anti-inflammatory, antioxidant and anti-bacterial activities to facilitate skin tissue engineering. The present study aims to develop poly-ε-caprolactone (PCL)/ AV containing curcumin (CUR), and TCH loaded hybrid nanofibrous scaffolds to validate the synergistic effect on the fibroblast proliferation and antimicrobial activity against Gram-positive and Gram-negative bacteria for wound healing. PCL/AV, PCL/CUR, PCL/AV/CUR and PCL/AV/TCH hybrid nanofibrous mats were fabricated using an electrospinning technique and were characterized for surface morphology, the successful incorporation of active compounds, hydrophilicity and the mechanical property of nanofibers. SEM revealed that there was a decrease in the fiber diameter (ranging from 360 to 770 nm) upon the addition of AV, CUR and TCH in PCL nanofibers, which were randomly oriented with bead free morphology. FTIR spectra of various electrospun samples confirmed the successful incorporation of AV, CUR and TCH into the PCL nanofibers. The fabricated nanofibrous scaffolds possessed mechanical properties within the range of human skin. The biocompatibility of electrospun nanofibrous scaffolds were evaluated on primary human dermal fibroblasts (hDF) by MTS assay, CMFDA, Sirius red and F-actin stainings. The results showed that the fabricated PCL/AV/CUR and PCL/AV/TCH nanofibrous scaffolds were non-toxic and had the potential for wound healing applications. The disc diffusion assay confirmed that the electrospun nanofibrous scaffolds possessed antibacterial activity and provided an effective wound dressing for skin tissue engineering.

Candidate Polyurethanes Based on Castor Oil (Ricinus communis), with Polycaprolactone Diol and Chitosan Additions, for Use in Biomedical Applications

Polyurethanes are widely used in the development of medical devices due to their biocompatibility, degradability, non-toxicity and chemical versatility. Polyurethanes were obtained from polyols derived from castor oil, and isophorone diisocyanate, with the incorporation of polycaprolactone-diol (15% w/w) and chitosan (3% w/w). The objective of this research was to evaluate the effect of the type of polyol and the incorporation of polycaprolactone-diol and chitosan on the mechanical and biological properties of the polyurethanes to identify the optimal ones for applications such as wound dressings or tissue engineering. Polyurethanes were characterized by stress-strain, contact angle by sessile drop method, thermogravimetric analysis, differential scanning calorimetry, water uptake and in vitro degradation by enzymatic processes. In vitro biological properties were evaluated by a 24 h cytotoxicity test using the colorimetric assay MTT and the LIVE/DEAD kit with cell line L-929 (mouse embryonic fibroblasts). In vitro evaluation of the possible inflammatory effect of polyurethane-based materials was evaluated by means of the expression of anti-inflammatory and proinflammatory cytokines expressed in a cellular model such as THP-1 cells by means of the MILLIPLEX® MAP kit. The modification of polyols derived from castor oil increases the mechanical properties of interest for a wide range of applications. The polyurethanes evaluated did not generate a cytotoxic effect on the evaluated cell line. The assessed polyurethanes are suggested as possible candidate biomaterials for wound dressings due to their improved mechanical properties and biocompatibility.