2021, Vol. 6, No. 1
Over the last couple of decades, the introduction of living systems to material science for the synthesis of functional materials from biological resources is receiving immense consideration. This is also in accordance with the need for green and sustainable development of new materials. For example, the growing concerns of the degradation of synthetic plastics are shifting the direction of materials-related research to the use of polymeric materials acquired from renewable resources. For example, the fungal mycelium-based materials are produced by growing the vegetative part of mushroom-forming fungi on different organic substrates. Such fungi are known for their ability to degrade agricultural wastes such as straws and sawdust. The mycelium-based composites having tailored structural, physical, chemical, mechanical, and biological properties are relying on the strain, feeding substrate, and the manufacturing process. The mycelium cell wall mainly contains the chitin, glucans, proteins, and lipids, whose concentrations depend upon the feeding substrate that ultimately defines the final properties of the synthesized materials. The mycelium-based functional materials with tunable properties are synthesized by selecting the desired components and the synthesis method. The pure and composites of stiff, elastic, porous, less dense, fast-growing, and low-cost mycelium-derived materials with efficient antimicrobial, antioxidant, and skin whitening properties pave their way in various applications such as construction, packaging, medicine, and cosmetics. This review describes the synthesis and structural organization of mycelium-based materials. It further discusses the effect of different factors on the material properties. Finally, it summarizes different applications of mycelium-based materials in medicine, cosmetics, packaging, and construction fields.
The use of polymer based composites in the treatment of skin tissue damages, has got huge attention in clinical demand, which enforced the scientists to improve the methods of biopolymer designing in order to obtain highly efficient system for complete restoration of damaged tissue. In last few decades, chitosan-based biomaterials have major applications in skin tissue engineering due to its biocompatible, hemostatic, antimicrobial and biodegradable capabilities. This article overviewed the promising biological properties of chitosan and further discussed the various preparation methods involved in chitosan-based biomaterials. In addition, this review also gave a comprehensive discussion of different forms of chitosan-based biomaterials including membrane, sponge, nanofiber and hydrogel that were extensively employed in skin tissue engineering. This review will help to form a base for the advanced applications of chitosan-based biomaterials in treatment of skin tissue damages.
Bacterial cellulose (BC) has been extensively explored as biomaterial for various biomedical applications owing to its non-toxic nature and unique structural morphology and impressive physico-chemical and mechanical properties. However, its high production cost and lack of antimicrobial activity have restricted its large-scale production and therapeutic applications. Therefore, the current study is aimed to devise a strategy for low-cost BC production and develop its composite with bioactive materials to bless it with antimicrobial activity. Herein, 5 mm thick reticulated fibrous and highly porous BC was produced by utilizing the wasted rotten tomatoes as the production medium. The produced bacterial cellulose waste (BCW) (i.e., produced from wastes) was ex-situ modified with bioactive plant extract (PE) obtained from Euclea schimperi, and the bactericidal activity of the developed BCW/PE was evaluated against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli through disc diffusion and colony forming unit (CFU) count methods. The BCW/PE composite showed high bactericidal activities against S. aureus and produced clear inhibition zone whereas negligible activity was observed against E. coli, indicating its bactericidal activity mainly against the Gram-positive bacterium. Overall, this study illustrates that there is a huge potential for developing valuable biomaterials from food wastes and utilizing their liquid holding capabilities for value-added applications in medical and pharmaceutical fields.
In face of scarcity in the supply of non-traditional Brazilian woods properly treated for use in high quality musical instruments, pieces of Amazonian wood species muiracatiara (Astronium lecointei) and maçaranduba (Manilkara huberi) purchased in the common internal Brazilian timber market were examined. These species were pre-selected for use in fingerboards of acoustic and electric guitars due to similar properties with ebony (Diospyros crassiflora). Variabilities of elastic modulus parallel to grain and density were investigated inside wooden pieces. In addition, referred parameters were used in calculation of speed of sound. Statistical tests were performed in order to compare both species and revealed inequality for variances of dynamic elastic modulus (Ed) and speed of sound, but equality for density. Equality of means was also examined via unequal variance t-test. Despite color differences, lower variability of M. huberi led to the indication of this species as likely capable to substitute satisfactorily ebony in fingerboards manufacturing.
Furfural is an alternative feedstock and has been used for the production of maleic acid (MA) and fumaric acid (FA) by an oxidation process. Deep eutectic solvents (DESs) were used as the green solvents while sodium chlorate was used as an oxidant and vanadium pentoxide was used as the catalyst at 70–90 ℃ under atmospheric pressure. It was found that several acidic DESs are valid, such as acetic acid/choline chloride (AA/ChCl) and propionic acid/choline chloride (PA/ChCl), and AA/ChCl DES was selected as the solvent for the conversion. The optimal DES is AA/ChCl, and the effect of the amount of oxidant, time, and temperature on the yield of the MA and FA has been systematically studied, and the conversion of furfural can reach 100% while the yield of the MA and FA reached 66.5% under reaction temperature of 80 ℃ for 12 h, which provides a new green route to synthesis valuable monomers from furfural.
The key process parameters for the hydrolysis and fermentation of Colocynthis vulgaris Shrad seeds shell (CVSSS) were optimized using the Box-Behnken Design (BBD) of Response Surface Methodology (RSM). Kinetic study was also carried out. The proximate analysis of the CVSSS was done by the method of the Association of Organic and Applied Chemistry (AOAC). Enzymatic hydrolysis was experimented by using Aspergillus Niger as a crude enzyme isolated from soil at sawdust dump site and screened for cellulosic activities. Factors that affected the hydrolysis of the CVSSS were screened by using the Greco-Latin square design of experiment. However, for Saccharomyces cerevisiae, factors that affected the fermentation of the CVSSS were screened by using the same Greco-Latin square design of experiment. Meanwhile, the result of the proximate analysis revealed that the CVSSS had 73.54% cellulose which could be converted to bioethanol. It was established that temperature, pH and time had significant effect on hydrolysis, while the optimum results were obtained at 46.8 ℃, 3.32 d, 5.68 and 59.87% for temperature, time, pH and glucose yield, respectively. Temperature, yeast dosage, pH and time had significant effect on fermentation, while the optimum results from optimization were found to be 33.58 ℃, 7.0, 3.55 d, 1.65 g per 50 mL and 25.6% for temperature, pH, time, yeast dosage and ethanol yield, respectively. The kinetics of both the enzymatic hydrolysis and fermentation agreed with the Michealis-Menten kinetic model with the correlation coefficients (R2) of 0.9708 and 0.8773, respectively. However, from the error analysis, the experimental and predicted values had a very good relationship as described by Michaelis-Menten model.
In order to solve the problem of poor thermal insulation in the current wood-plastic building, two kinds of structural wood wall integrated with wood plastic composite (WPC) are designed, and the thermal insulation performances of the walls are studied. The results show that the WPC integrated wall with frame-shear structure has a good stability, and the excellent performance of the WPC can be fully realized. Wall studs and wall panels are important factors affecting the thermal performance of the walls. Wood plastic materials can meet the thermal performance requirements of the walls. The single-layer frame walls and double-layer frame walls integrated with the WPC both have a good thermal performance. According to 'Design Standard for Energy Efficiency of Public Buildings (GB 50189-2015)', the heat transfer coefficient of the single-layer frame wall integrated with 20 mm thick WPC wall boards and WPC wall studs is 0.414 W/(m2·K), which can meet the standard of wall thermal level Ⅱt and is suitable for cold areas. The heat transfer coefficient of the double-layer frame wall integrated with 50 mm thick WPC wall panel and WPC wall studs is 0.207 W/(m2·K), which can meet the standard of wall thermal level Ⅰt and is suitable for severe cold areas.
The aim of the present study was to develop antibacterial cellulose (cotton) nanocomposite fabrics (CNCFs) with in situ generated silver nanoparticles using medicinal plant Vitex leaf extract. The developed CNCFs were characterized by scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD) and antibacterial tests. Further, these CNCFs possessed good antibacterial activities. These CNCFs prepared using simple and environmentally friendly method can be considered for medical applications in, such as, surgical aprons, wound cleaning, wound dressing, and hospital bed materials.