Revised Manuscript with Corrections: Polyurethane-Based Conductive Composites: From Synthesis to Applications.

The purpose of this review article is to outline the extended applications of polyurethane (PU)-based nanocomposites incorporated with conductive polymeric particles as well as to condense an outline on the chemistry and fabrication of polyurethanes (PUs). Additionally, we discuss related research trends of PU-based conducting materials for EMI shielding, sensors, coating, films, and foams, in particular those from the past 10 years. PU is generally an electrical insulator and behaves as a dielectric material. The electrical conductivity of PU is imparted by the addition of metal nanoparticles, and increases with the enhancing aspect ratio and ordering in structure, as happens in the case of conducting polymer fibrils or reduced graphene oxide (rGO). Nanocomposites with good electrical conductivity exhibit noticeable changes based on the remarkable electric properties of nanomaterials such as graphene, RGO, and multi-walled carbon nanotubes (MWCNTs). Recently, conducting polymers, including PANI, PPY, PTh, and their derivatives, have been popularly engaged as incorporated fillers into PU substrates. This review also discusses additional challenges and future-oriented perspectives combined with here-and-now practicableness.

Triple-Networked Hybrid Hydrogels Reinforced with Montmorillonite Clay and Graphene Nanoplatelets for Soft and Hard Tissue Regeneration.

Hydrogel is a three-dimensional (3D) soft and highly hydrophilic, polymeric network that can swell in water and imbibe a high amount of water or biological fluids. Hydrogels have been used widely in various biomedical applications. Hydrogel may provide a fluidic tissue-like 3D microenvironment by maintaining the original network for tissue engineering. However, their low mechanical performances limit their broad applicability in various functional tissues. This property causes substantial challenges in designing and preparing strong hydrogel networks. Therefore, we report the triple-networked hybrid hydrogel network with enhanced mechanical properties by incorporating dual-crosslinking and nanofillers (e.g., montmorillonite (MMT), graphene nanoplatelets (GNPs)). In this study, we prepared hybrid hydrogels composed of polyacrylamide, poly (vinyl alcohol), sodium alginate, MMT, and MMT/GNPs through dynamic crosslinking. The freeze-dried hybrid hydrogels showed good 3D porous architecture. The results exhibited a magnificent porous structure, interconnected pore-network surface morphology, enhanced mechanical properties, and cellular activity of hybrid hydrogels.

Advances in Protein-Based Materials: From Origin to Novel Biomaterials.

Biomaterials play a very important role in biomedicine and tissue engineering where they directly affect the cellular activities and their microenvironment . Myriad of techniques have been employed to fabricate a vast number natural, artificial and recombinant polymer s in order to harness these biomaterials in tissue regene ration , drug delivery and various other applications. Despite of tremendous efforts made in this field during last few decades, advanced and new generation biomaterials are still lacking. Protein based biomaterials have emerged as an attractive alternatives due to their intrinsic properties like cell to cell interaction , structural support and cellular communications. Several protein based biomaterials like, collagen , keratin , elastin , silk protein and more recently recombinant protein s are being utilized in a number of biomedical and biotechnological processes. These protein-based biomaterials have enormous capabilities, which can completely revolutionize the biomaterial world. In this review, we address an up-to date review on the novel, protein-based biomaterials used for biomedical field including tissue engineering, medical science, regenerative medicine as well as drug delivery. Further, we have also emphasized the novel fabrication techniques associated with protein-based materials and implication of these biomaterials in the domain of biomedical engineering .

Fungal Carboxymethyl Chitosan-Impregnated Bacterial Cellulose Hydrogel as Wound-Dressing Agent.

Bacterial cellulose (BC) produced by Gluconoacetobacter hansenii is a suitable polymeric fiber network for wound-dressing purposes, but its lack of antibacterial properties limits it from healing bacterial wounds. We developed hydrogels by impregnating fungal-derived carboxymethyl chitosan to BC fiber networks using a simple solution immersion method. The CMCS-BC hydrogels were characterized using various characterization techniques such as XRD, FTIR, water contact angle measurements, TGA, and SEM to know the physiochemical properties. The results show that the impregnation of CMCS into BC fiber networks greatly influences BC's improving hydrophilic nature, which is crucial for wound healing applications. Furthermore, the CMCS-BC hydrogels were studied for biocompatibility analysis with skin fibroblast cells. The results revealed that by increasing the CMCS content in the BC, biocompatibility, cell attachment, and spreading capacity also increase. The antibacterial activity of CMCS-BC hydrogels is shown using the CFU method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). As a result, the CMCS-BC hydrogels exhibit more suitable antibacterial properties than those without BC due to the CMCS having amino groups that enhance antibacterial properties. Therefore, CMCS-BC hydrogels can be considered suitable for antibacterial wound dressing applications.

Cuminaldehyde-3-hydroxy-2-napthoichydrazone: Synthesis, effect of solvents, nonlinear optical activity, antioxidant activity, antimicrobial activity, and DFT analysis.

Hydrazones derived from essential oil components have attracted considerable interest because of their antimicrobial, antioxidant, and nonlinear optical applications. In the present work, a new essential oil component derivative (EOCD), cuminaldehyde-3-hydroxy-2-napthoichydrazone (CHNH), was synthesized. EOCD was characterized by Fourier transform infrared spectroscopy, mass spectrometry, nuclear magnetic resonance (1H and 13C) spectroscopy, elemental analysis, ultraviolet-visible absorption spectroscopy, and field-emission scanning electron microscopy. Thermogravimetric analysis and X-ray diffraction showed a higher stability, phase-pure, and non-existent isomorphic phase transition in EOCD. Solvent studies indicated that the normal emission band was caused by the locally excited state and the large Stokes shifted emission originated because of the twisted intramolecular charge transfer. The EOCD possessed higher direct and indirect band gap energies of 3.05 eV and 2.90 eV respectively, as determined by the Kubelka-Munk algorithm. The outcomes of frontier molecular orbitals, global reactivity descriptors, Mulliken, and molecular electrostatic potential surface by density functional theory calculations revealed high intramolecular charge transfer, good realistic stability, and high reactiveness of EOCD. The hydrazone EOCD exhibited higher hyperpolarizability (18.248 × 10-30 esu) in comparison to urea. Antioxidant test results indicated that EOCD showed significant antioxidant activity (p < 0.05), as determined by the DPPH radical scavenging assay. The newly synthesized EOCD showed no antifungal activity against Aspergillus flavus. Additionally, the EOCD showed good antibacterial activity against Escherichia coli and Bacillus subtilis.

Bacterial Cellulose and Its Applications.

The sharp increase in the use of cellulose seems to be in increasing demand in wood; much more research related to sustainable or alternative materials is necessary as a lot of the arable land and natural resources use is unsustainable. In accordance, attention has focused on bacterial cellulose as a new functional material. It possesses a three-dimensional, gelatinous structure consisting of cellulose with mechanical and thermal properties. Moreover, while a plant-originated cellulose is composed of cellulose, hemi-cellulose, and lignin, bacterial cellulose attributable to the composition of a pure cellulose nanofiber mesh spun is not necessary in the elimination of other components. Moreover, due to its hydrophilic nature caused by binding water, consequently being a hydrogel as well as biocompatibility, it has only not only used in medical fields including artificial skin, cartilage, vessel, and wound dressing, but also in delivery; some products have even been commercialized. In addition, it is widely used in various technologies including food, paper, textile, electronic and electrical applications, and is being considered as a highly versatile green material with tremendous potential. However, many efforts have been conducted for the evolution of novel and sophisticated materials with environmental affinity, which accompany the empowerment and enhancement of specific properties. In this review article, we summarized only industry and research status regarding BC and contemplated its potential in the use of BC.

Novel biomimetic chitin-glucan polysaccharide nano/microfibrous fungal-scaffolds for tissue engineering applications.

Naturally occurring many biological structures have provided sources of inspiration for the fabrication of many novel nanostructures for various applications. Electrospun nano/microfibrous structures have great potential as scaffolds for cell attachment and proliferation in the field of tissue engineering. Here, for the first time, we report on the preparation of three-dimensional (3D) fungal mycelial mats with chitin-glucan polysaccharide cell walls as nano/microfibrous scaffolds for tissue engineering applications. Treatment of fungal-scaffolds (F-scaffolds) with ß-mercaptoethanol (BME) improved hemocompatibility, and conferred biocompatibility with respect to the adhesion and proliferation of human keratinocytes. Field-emission scanning electron microscopy (FE-SEM) of BME-treated F-scaffolds revealed a meshwork of nano- and micro-fibrous mycelial structures with an average diameter of 2.94 ± 0.96 µm (range 0.92-5.6 µm). Tensile testing showed F-scaffolds had a mean tensile strength of 0.192 ± 0.07 MPa and a mean elongation at break of 10.74 ± 2.53%, respectively. The degradation rate of the F-scaffolds showed ~19.2 ± 1.9% weight loss in 28 days. FE-SEM of BME-treated F-scaffolds seeded with keratinocytes showed deposition of extracellular matrix (ECM) components and the formation of cell sheets in 14 days. In addition, the in vitro cytocompatibility of BME-treated F-scaffolds with keratinocytes was analyzed using resazurin-based assay, which showed a time-dependent increase in metabolic activity up to culture day 21. Overall, this novel investigation shows that filamentous fungal mats with a nano/microfibrous mycelial architecture are potentially useful for tissue engineering applications.

Effect of Extracts of Terminalia chebula on Proliferation of Keratinocytes and Fibroblasts Cells: An Alternative Approach for Wound Healing.

Terminalia chebula is one of the traditional medicines used in the treatment of many diseases. In the present work, different concentrations of various organic and aqueous extracts (solvent-free) of T. chebula were tested on fibroblast (L929) and keratinocytes cells to evaluate its biocompatible concentration by using MTT and live-dead viability/cytotoxic assay. These extracts were found to be effective in decreasing the ammonia accumulation in the media, thereby reducing its toxic effect on cells. DPPH assay further confirmed the free-radical scavenging ability of the extracts which increased with the increase in concentration of each extract. Cell proliferation/apoptosis, cytoskeletal structure, and ECM production were further evaluated by live-dead assay and phalloidin/cytokeratin staining, respectively. The cytoskeletal structure and ECM secretion of the cells treated with extracts showed higher cellular activity in comparison to control. In conclusion, we have demonstrated the effect of these extracts of T. chebula on both types of skin cells and optimized concentration in which it could be used as a bioactive component for wound healing applications by increasing cell proliferation and decreasing free-radical production without affecting the normal cellular matrix. It can also find applications in other therapeutics applications where ammonia toxicity is a limiting factor.

Engineering three-dimensional macroporous hydroxyethyl methacrylate-alginate-gelatin cryogel for growth and proliferation of lung epithelial cells.

Three-dimensional (3D) growth of cell is of particular interest in the field of tissue engineering and regenerative medicine. Scaffolds used for this purpose are often tailor-made to mimic the microenvironment and the extracellular matrix of the tissue with defined role such as to provide appropriate structural, chemical, and mechanical support. The aim of the study was to design the macroporous matrix with potential in the field of tissue engineering especially for lung muscle regeneration. Blend of hydroxyethyl methacrylate-alginate-gelatin (HAG) cryogel scaffold was synthesized using cryogelation technique and this polymer material combination is being reported first time. The rheology study showed the elastic property of the material in wet state with no variation in storage modulus (G'), loss modulus (G″), and phase angle upon temperature variation. The microcomputer tomography (micro-CT) analysis confirmed the homogenous polymer structure with average pore diameter of 84 µm. Scaffold synthesized using polymer combinations which is mixture of polysaccharide (alginate) and protein (gelatin) provides supportive environment for human lung epithelial cell proliferation confirmed by cytoskeletal stain phalloidin and nuclei staining 4',6-diamidino-2-phenylindole checked for over three weeks. The in vivo biocompatibility was further performed which showed integration of scaffold to the surrounding tissue with ability to recruit cells. However, at first week, small amount of infiltrating mast cells were found which subsequently diminished in following weeks. Immunohistochemistry for dendritic cells confirmed in vivo biocompatible nature of the HAG scaffold. The mechanical strength, stiffness, elastic measurements, in vivo compatibility, and in vitro lung cell proliferation show the potentiality of HAG materials for lung tissue engineering.