Silk-reinforced polylactic acid/poly ε-caprolactone composites containing 1−7 wt % of silk fibers were fabricated through the melt-mixing method. The composites were then characterized by implementing Fourier transform infrared (FTIR), differential scanning calorimetry (DSC) and rheometry to investigate functional groups, thermal properties, rheological properties, and intrinsic viscosities of each composite. The crystallinity of the composites was found to decrease upon addition of silk, while, both storage modulus (G′) and loss modulus (G″) were increased which is an indication of interface bonding between the polymer and silk. The composite containing 5% silk fiber (PLACLS5) showed the optimum results. The composites' morphological analysis was conducted by scanning electron micrograph coupled with energy dispersive X-ray (SEM-EDX) mapping to assess the fiber dispersion in the composite matrix. The contact angle measurements and in vitro degradation were performed to evaluate the hydrophilicity, free surface energy, and hydrolytic degradation of the composites. The results implied that addition of higher contents of silk fiber could reduce the degradation duration of the composites, which is due to the high hydrophilicity of the fiber, uniform fiber dispersion within the matrix, the porous structure, and consequently, the hydrophilic behavior of the composites. These composites can be great alternatives for both soft and hard tissue engineering applications.
Perlite nano-particles were prepared through a mechanical grinding process and surface-modified by poly(methyl hydrogen siloxane) (PMHS). Nanocomposites based on low-density polyethylene (LDPE) and different compositions of treated and untreated nano particles were prepared via melt mixing of the ingredients on a co-rotating twin screw extruder. Laser light-scattering (LLS) was used to analyze the mean particle size of the nano perlite while Fourier-transform infrared spectroscopy (FTIR) was employed to investigate surface modification of the particles. Scanning electron microscopy (SEM) was used to evaluate the dispersion status of the nano particles in the polymer matrix. Results indicated a relatively good dispersion of the particles (50-500 nm in size) within the LDPE matrix. Mechanical measurements showed remarkable increases in tensile strength and modulus of the nanocomposites containing surface modified perlite, compared to the neat polymer. Also, flexural strength and modulus were increased with increasing nano perlite, while impact properties were reduced.
Nanocomposites based on low-density polyethylene (LDPE) and nano perlite were prepared at various perlite contents via melt mixing in a twin-screw extruder. Rheological measurements, dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA) tests were carried out on the nanocomposites. The results confirmed the establishment of interactions between LDPE matrix and treated nano perlite. In addition, dynamic mechanical properties and thermal stability of the treated nanocomposites were improved.
Ethosomes are most commonly used vesicular delivery system compared to other lipidic vesicles due to its ethanolic content. Thymoquinone (TQ), the main biologically active complex of Black Cumin seed, has established anticancer activities in several tumors. In this work, the preparation of ethosome for TQ encapsulation by response surface method (RSM) was developed. Central composite design (CCD) was used to optimize three effective parameters involved in ethosome structure including phospholipid, cholesterol and ethanol concentration and the combined effects of them, as well. The obtained optimum values for the variables were phospholipid 5% (W/W), ethanol 45% (V/V) and cholesterol 1.5% (W/W) which were validated by experimental assay. The ethosomal formulation was more characterized for vesicle shape, size, zeta potential and entrapment efficiency percentage. The result showed an efficiency of 99% for drug entrapment with average vesicle size and zeta potential of 20 ± 1 nm and − 63 ± 2 mv, respectively. A quadratic model with a high adequacy (R 2) for size and zeta potential of 0.9319 and 0.9338, respectively, was resulted from RSM and experimental assay. Thymoquinone (TQ) encapsulated in optimized ethosome. Also, cellular toxicity and release test was done. The toxicity and release curves were obtained and the cytotoxic activity of the ethosomic TQ against MCF-7 cell lines was greater than free TQ. IC50 values of free TQ, ethosomic TQ, were found to be 1.10 µg/ml, 0.95 µg/ml, respectively. The generated model suggests a new approach to prediction and experimental lipidic carriers.
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