The Effect of Poly (Glycerol Sebacate) Incorporation within Hybrid Chitin–Lignin Sol–Gel Nanofibrous Scaffolds

Chitin and lignin primarily accumulate as bio-waste resulting from byproducts of crustacean crusts and plant biomass. Recently, their use has been proposed for diverse and unique bioengineering applications, amongst others. However, their weak mechanical properties need to be improved in order to facilitate their industrial utilization. In this paper, we fabricated hybrid fibers composed of a chitin–lignin (CL)-based sol–gel mixture and elastomeric poly (glycerol sebacate) (PGS) using a standard electrospinning approach. Obtained results showed that PGS could be coherently blended with the sol–gel mixture to form a nanofibrous scaffold exhibiting remarkable mechanical performance and improved antibacterial and antifungal activity. The developed hybrid fibers showed promising potential in advanced biomedical applications such as wound care products. Ultimately, recycling these sustainable biopolymers and other bio-wastes alike could propel a “greener” economy

Characterization, mechanistic analysis and improving the properties of denture adhesives.

OBJECTIVE:Denture adhesives are widely used to avoid the detachment and sliding of dentures. However, the adhesion properties can be affected by variation in mouth conditions such as the level of salivation. The objective of this study was to understand the effect of environmental conditions on the adhesion properties of a commercially available denture adhesive named as Poligrip® Free manufactured by GlaxoSmithKline Ltd., UK and to identify the reasons for the observed variation in its adhesion strength. METHODS:The failure mechanisms of denture adhesive have been assessed through using different physical, mechanical and thermal characterization experiments. All methods were used in different pH, temperatures, and salivation conditions and at the end, a strategy was proposed to overcome the failure of the paste in hyposalivation as well. RESULTS:In vitro models mimicking the denture gingival interface were designed to evaluate the adhesion properties of the investigated adhesive. Changes in the adhesion strength in response to three major factors related to the oral conditions including level of salivation, pH, and temperature were measured. The results of lap shear, tensile test, and internal interactions suggested a cohesion failure, where the lowest adhesion strength was due to hyposalivation. Fourier transform infrared spectroscopy (FTIR) and rheological analysis confirmed the importance of hydrogen bonds and hydration in the adhesion strength of the paste. SIGNIFICANCE:The investigated scenarios are widely observed in patient using denture adhesives and the clinical reports have indicated the inconsistency in adhesion strength of the commercial products. After identifying the potential reasons for such behavior, methods such as the addition of tripropylene glycol methyl ether (TPME) to enhance internal hydrogen bonds between the polymers are proposed to improve adhesion in the hyposalivation scenario

Cationic Water-Soluble Conjugated Polyelectrolytes/Graphene Oxide Nanocomposites as Efficient Green Hole Injection Layers in Organic Light Emitting Diodes

The current research presents using a nanocomposite comprising of a cationic conjugated polyelectrolyte (CPE), poly­[(2,5-bis­(2-(<i>N</i>,<i>N</i>-diethylammonium bromide)­ethoxy)-1,4-phenylene)-<i>alt</i>-1,4-phenylene] or (PPPNEt₂·HBr), with graphene oxide (GO) as a new hole injection layer (HIL) for organic light emitting diodes. It is demonstrated that using the designed ionically functionalized water-soluble conjugated polymers instead of polyethylene dioxythiophene:polystyrenesulfonate (PEDOT:PSS) is a promising approach to overcome the strong acidic nature of PEDOT:PSS besides excluding its nonconductive PSS part. As the other aspiration of this work, we introduce a good partner for dissolving and spin-casting of GO as a simple and economic technique to use the hole conductive and electron blocking nature of GO in the hole injection portion of assembled devices. Using this new binary blend showed enhanced charge carrier mobility, good electroluminescence, and <i>J</i>–<i>V</i> characteristics in comparison with conventional devices. Such improvement is interpreted with induced ion space charge of HIL at the interface and resulting electric field screening effect due to ion migration

Mechanical and Biochemical Stimulation of 3D Multilayered Scaffolds for Tendon Tissue Engineering

Tendon injuries are frequent and occur in the elderly, young, and athletic populations. The inadequate number of donors combined with many challenges associated with autografts, allografts, xenografts, and prosthetic devices have added to the value of engineering biological substitutes, which can be implanted to repair the damaged tendons. Electrospun scaffolds have the potential to mimic the native tissue structure along with desired mechanical properties and, thus, have attracted noticeable attention. In order to improve the biological responses of these fibrous structures, we designed and fabricated 3D multilayered composite scaffolds, where an electrospun nanofibrous substrate was coated with a thin layer of cell-laden hydrogel. The whole construct composition was optimized to achieve adequate mechanical and physical properties as well as cell viability and proliferation. Mesenchymal stem cells (MSCs) were differentiated by the addition of bone morphogenetic protein 12 (BMP-12). To mimic the natural function of tendons, the cell-laden scaffolds were mechanically stimulated using a custom-built bioreactor. The synergistic effect of mechanical and biochemical stimulation was observed in terms of enhanced cell viability, proliferation, alignment, and tenogenic differentiation. The results suggested that the proposed constructs can be used for engineering functional tendons

Mechanical and Biochemical Stimulation of 3D Multilayered Scaffolds for Tendon Tissue Engineering.

Tendon injuries are frequent and occur in the elderly, young, and athletic populations. The inadequate number of donors combined with many challenges associated with autografts, allografts, xenografts, and prosthetic devices have added to the value of engineering biological substitutes, which can be implanted to repair the damaged tendons. Electrospun scaffolds have the potential to mimic the native tissue structure along with desired mechanical properties and, thus, have attracted noticeable attention. In order to improve the biological responses of these fibrous structures, we designed and fabricated 3D multilayered composite scaffolds, where an electrospun nanofibrous substrate was coated with a thin layer of cell-laden hydrogel. The whole construct composition was optimized to achieve adequate mechanical and physical properties as well as cell viability and proliferation. Mesenchymal stem cells (MSCs) were differentiated by the addition of bone morphogenetic protein 12 (BMP-12). To mimic the natural function of tendons, the cell-laden scaffolds were mechanically stimulated using a custom-built bioreactor. The synergistic effect of mechanical and biochemical stimulation was observed in terms of enhanced cell viability, proliferation, alignment, and tenogenic differentiation. The results suggested that the proposed constructs can be used for engineering functional tendons

Glucose‐Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid

Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide‐co‐poly(ethylene glycol) diacrylate) cores functionalized with phenylboronic acid. The complexation of the phenylboronic acid and cis‐diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range