Design and characterization of Poly(glycerol sebacate)/Poly(3-hydroxybutyrate)/bioglass/curcumin nanocomposite scaffold for wound healing application.

Various applications have been developed for biopolymers, such as scaffolds for tissue engineering. Nanocomposite materials are considered promising for wound healing applications in many unique fields. New nanocomposite scaffold biopolymers were synthesized through the salt leaching technique. Curcumin and bioglass nanoparticles as antibacterial agents were added to Poly(glycerol sebacate)/Poly(3-hydroxybutyrate) nanocomposite scaffolds with different concentrations. Several properties were explored, including morphology, physicomechanical properties, contact angles, antibacterial efficacy, and in vitro studies. The morphology of nanocomposite scaffolds was characterized using SEM and EDX. Additionally, nanocomposite scaffolds Poly(glycerol sebacate)/Poly(3-hydroxybutyrate) showed a water contact angle of 79.8°. The hydrophilicity and water vapor transition rate significantly improved by adding bioglass nanoparticles which were 55° and 2182 g m-2 day-1 for Poly(glycerol sebacate)/Poly(3-hydroxybutyrate)/5 %Bioglass/3 %Curcumin. Samples containing 3 wt% Curcumin had the highest swelling ratio (347 ± 12 %) and the lowest water contact angle. Furthermore, NIH/3T3 fibroblast cells showed significant attachment and viability in in-vitro biocompatibility tests. Bioglass and Curcumin inhibited bacterial growth effectively. Additionally, an in-vitro cell viability, cell attachment, and in-vitro scratch wound healing assay demonstrated that the Poly(glycerol sebacate)/Poly(3-hydroxybutyrates)/5 % Bioglass/3 % Curcumin nanocomposite scaffold could promote wound healing.

Design and characterization of bio-elastomers containing biomaterials for tissue engineering application.

AIMS: The purpose of this research is to fabricate a new type of bio-elastomer based on Poly(glycerol-sebacate)-co-Poly(hydroxybutyrate) (PGS-co-PHB) with varying amounts of bioglass 45S5 (BG) nanoparticles (1, 3 and 5 wt%) through the green polycondensation polymerization for tissue engineering applications. MATERIALS AND METHODS: Fabricated composite films are characterized by FTIR, 1H NMR, SEM, EDX, contact angle, DMTA, biodegradability, and biocompatibility. The cell viability and morphology of L929 cells are investigated by indirect MTT assay and SEM analysis, and the antibacterial activity of composite film is determined by the disk diffusion method. Furthermore, the bioactivity of the composite film is measured by soaking in simulated body fluid (SBF), and XRD and SEM determined the formation of a hydroxyapatite (HA) layer. KEY FINDINGS: The hydrophilicity improved by adding BG nanoparticles, and the water contact angle was reduced to 63.46°. Furthermore, the average cell viability of composite film is about 94 %, and the SEM images show that L929 fibroblast cells are well spread on the surface of the composite film. BG has a significant influence on the antibacterial activity of composite film as PGS-co-PHB/5 %BG shows more antibacterial properties due to the higher amount of BG. SEM and XRD analyses confirmed the presence of crystalline HA on the surfaces of the composite film, indicating their potential for high bioactivity. SIGNIFICANCE: The results indicate that the antibacterial composite films are excellent supports for cell growth and proliferation and could be promising candidates for tissue engineering applications.

Fabrication and characterization of polycaprolactone/chitosan nanofibers containing antibacterial agents of curcumin and ZnO nanoparticles for use as wound dressing.

The potential of the nanoscale structure is utilized by electrospun nanofibers, which are promising materials for wound dressings. Here, we prepared wound dressings constituting polycaprolactone (PCL) and chitosan (CS). Curcumin (Cur) and zinc oxide nanoparticles (ZnO) as antibacterial agents were embedded in PCL/CS electrospun nanofibers and different properties including morphology, physicomechanical, interaction with water, antibacterial efficiency, and in vitro studies were investigated. SEM images confirmed the nanofibrous structure of samples with 100 ± 5 to 212 ± 25 nm in average diameter. Elemental analysis of nanofibers showed a good distribution of ZnO along nanofibers which not only caused decreasing in nanofiber diameter but also increased tensile strength of nanofibers up to 2.9 ± 0.5 MPa and with good elongation at break of 39 ± 2.9. ZnO nanoparticles also facilitated the interaction of nanofibers with water, and this led to the highest water vapor transition rate, which was equal to 0.28 ± 0.02 g cm-2 day-1. The sample containing 3 wt% Cur had the highest water uptake value (367 ± 15%) and the lowest water contact angle (78 ± 3.7°), although Cur has a hydrophobic nature. The release profile of Cur showed a two-stage release and the Peppas model predicted a non-fickian diffusion. Simultaneous incorporation of CS, ZnO, and Cur effectively inhibited bacterial growth. In addition, in vitro studies represented that high content of Cur decreases cell viability and cell attachment. The outcomes from the fabricated nanofibrous scaffolds demonstrated appropriate properties for application as a wound dressing.

Multifunctional Gold Helix Phototheranostic Biohybrid That Enables Targeted Image-Guided Photothermal Therapy in Breast Cancer.

The preparation of multifunctional smart theranostic systems is commonly achieved through complicated strategies, limiting their biomedical applications. Spirulina platensis (SP) microalgae, as a natural helix with some of the intrinsic theranostic functionalities (e.g., fluorescent and photosensitizer pigments), not only facilitates the fabrication process but also guarantees their biosafety for clinical applications. Herein, the helical architecture of gold nanoparticles (AuNPs) based on a SP biotemplate was engineered as a safe, biodegradable, and tumor-targeted biohybrid for imaging-guided photothermal therapy (PTT) to combat triple-negative breast cancer. The quasi-spherical AuNPs were embedded throughout the SP cell (Au-SP) with minimally involved reagents, only by controlling the original morphological stability of SP through pH adjustment of the synthesis media. SP thiolation increased the localization of AuNPs selectively on the cell wall without using a reducing agent (Au-TSP). SP autofluorescence, along with the high X-ray absorption of AuNPs, was employed for dual-modal fluorescence and computed tomography (FL/CT) imaging. Furthermore, the theranostic efficacy of Au-SP was improved through a targeting process with folic acid (Au-SP@CF). High tumor inhibition effects were obtained by the excellent photothermal performance of Au-SP@CF in both in vitro and in vivo analyses. Of particular note, a comparison of the photothermal effect of Au-SP@CF with the naked SP and calcined form of Au-SP@CF not only indicated the key role of the helical architecture of AuNPs in achieving a high photothermal effect but also led to the formation of new gold microspiral biohybrids (Au-MS) over the calcination process. In short, well-controllable immobilization of AuNPs, appropriate biodegradability, good hemocompatibility, long-term biosafety, accurate imaging, high tumor suppression, and low tumor metastasis effects under laser irradiation are an array of intriguing attributes, making the proposed biohybrid a promising theranostic system for FL/CT-imaging-guided PTT.

The Effect of Poly (Ethylene glycol) Emulation on the Degradation of PLA/Starch Composites.

As a hydrophilic renewable polymer, starch has been widely used in biocompatible plastics as a filler for more than two decades. The present study aimed at investigating the effects of polyethylene glycol (PEG), as a plasticizer, on the physicochemical properties of a hybrid composite-polylactic acid (PLA) and thermoplastic starch (TPS). A solvent evaporation process was adopted to gelatinize the starch and disparate PEG contents ranging from 3 to 15 wt.% (with respect to the sample weight) were examined. It was revealed that the increase in the PEG content was accompanied by an increment in the starch gelatinization degree. Referring to the microstructural analyses, the TPS/PLA mixture yielded a ductile hybrid composite with a fine morphology and a uniform phase. Nevertheless, two different solvents, including acetone and ethanol, were used to assess if they had any effect on the hybrid's morphology, tensile strength and thermal properties. It was found that ethanol culminated in a porous hybrid composite with a finer morphology and better starch distribution in the PLA structure than acetone. As the result of PEG addition to the composite, the crystallinity and tensile strength were decreased, whereas the elongation increased. The hydrolytic degradation of samples was assessed under different pH and thermal conditions. Moreover, the microbial degradation of the PLA/TPS hybrid composite containing different PEG molar fractions was investigated in the soil for 45 days. The rate of degradation in both hydrolytic and biodegradation increased in the samples with a higher amount of PEG with ethanol solvent.

Effect of Surface Treatment of Halloysite Nanotubes (HNTs) on the Kinetics of Epoxy Resin Cure with Amines.

The epoxy/clay nanocomposites have been extensively considered over years because of their low cost and excellent performance. Halloysite nanotubes (HNTs) are unique 1D natural nanofillers with a hollow tubular shape and high aspect ratio. To tackle poor dispersion of the pristine halloysite (P-HNT) in the epoxy matrix, alkali surface-treated HNT (A-HNT) and epoxy silane functionalized HNT (F-HNT) were developed and cured with epoxy resin. Nonisothermal differential scanning calorimetry (DSC) analyses were performed on epoxy nanocomposites containing 0.1 wt.% of P-HNT, A-HNT, and F-HNT. Quantitative analysis of the cure kinetics of epoxy/amine system made by isoconversional Kissinger-Akahira-Sunose (KAS) and Friedman methods made possible calculation of the activation energy (Eα) as a function of conversion (α). The activation energy gradually increased by increasing α due to the diffusion-control mechanism. However, the average value of Eα for nanocomposites was lower comparably, suggesting autocatalytic curing mechanism. Detailed assessment revealed that autocatalytic reaction degree, m increased at low heating rate from 0.107 for neat epoxy/amine system to 0.908 and 0.24 for epoxy/P-HNT and epoxy/A-HNT nanocomposites, respectively, whereas epoxy/F-HNT system had m value of 0.072 as a signature of dominance of non-catalytic reactions. At high heating rates, a similar behavior but not that significant was observed due to the accelerated gelation in the system. In fact, by the introduction of nanotubes the mobility of curing moieties decreased resulting in some deviation of experimental cure rate values from the predicted values obtained using KAS and Friedman methods.

Association of environmental exposure with hematological and oxidative stress alteration in gasoline station attendants.

Gasoline station attendants spend a great deal of their time in the direct exposure to noxious substances such as benzene and byproducts of gasoline combustion. Such occupational exposure increases the risk of oxidative stress. This study aimed to evaluate hematological and biochemical alterations among petrol station workers. Forty gas station attendants and 39 non-attendants were recruited as exposed and control subjects, respectively. Plasma samples were evaluated for hemoglobin, hematocrit, and red blood cell count via the Sysmex KX-21 analyzer. Then, oxidized hemoglobin, methemoglobin, and hemichrome were measured spectrophotometrically. Moreover, serum antioxidant capacity and protein oxidation were evaluated. The means ± SD of hemoglobin (16.76 ± 0.14 g/dl vs 15.25 ± 0.14 g/dl), hematocrit (49.11 ± 0.36% vs 45.37 ± 0.31%), RBC count (5.85 ± 0.06 mil/µl vs 5.33 ± 0.06 mil/µl), Met-HB (1.07 ± 0.07 g/dl vs 0.39 ± 0.04 g/dl), and hemichrome (0.80 ± 0.07 g/dl vs 0.37 ± 0.02 g/dl) in the exposed group were significantly greater than the control group (P < 0.001). The results of the independent-sample t test illustrated that the FRAP test value in the exposed group (0.23 ± 0.01 mM) was significantly lower than the control group (0.34 ± 0.01 mM), while the value of the plasma protein carbonyl test in the exposed group (7.47 ± 0.33 mmol/mg protein) was meaningfully greater than the control group (5.81 ± 0.19 mmol/mg protein) (P < 0.001). In conclusion, gas station attendants suffer from higher levels of oxidative stress, and they need to take antioxidants in order to minimize the effects of oxidative stress.

Agarose-based biomaterials for tissue engineering.

Agarose is a natural polysaccharide polymer having unique characteristics that give reason to consider it for tissue engineering applications. Special characteristics of agarose such as its excellent biocompatibility, thermo-reversible gelation behavior and physiochemical features support its use as a biomaterial for cell growth and/or controlled/localized drug delivery. The resemblance of this natural carbohydrate polymer to the extracellular matrix results in attractive features that bring about a strong interest in its usage in the field. The scope of this review is to summarize the extensive researches addressing agarose-based biomaterials in order to provide an in-depth understanding of its tissue engineering-related applications.

Controlled grafting of vinylic monomers on polyolefins: a robust mathematical modeling approach.

Experimental and mathematical modeling analyses were used for controlling melt free-radical grafting of vinylic monomers on polyolefins and, thereby, reducing the disturbance of undesired cross-linking of polyolefins. Response surface, desirability function, and artificial intelligence methodologies were blended to modeling/optimization of grafting reaction in terms of vinylic monomer content, peroxide initiator concentration, and melt-processing time. An in-house code was developed based on artificial neural network that learns and mimics processing torque and grafting of glycidyl methacrylate (GMA) typical vinylic monomer on high-density polyethylene (HDPE). Application of response surface and desirability function enabled concurrent optimization of processing torque and GMA grafting on HDPE, through which we quantified for the first time competition between parallel reactions taking place during melt processing: (i) desirable grafting of GMA on HDPE; (ii) undesirable cross-linking of HDPE. The proposed robust mathematical modeling approach can precisely learn the behavior of grafting reaction of vinylic monomers on polyolefins and be placed into practice in finding exact operating condition needed for efficient grafting of reactive monomers on polyolefins.