ABSTRACT
Currently, researchers are focusing on the development of nano-additive preservatives during the worldwide COVID-19 pandemic. This research aimed to constitute a small sized preservative nano-formulation which emerges from the biopolymer carboxymethyl cellulose (a green stabilizing agent) and hydromagnesite stromatolite (a fossilized natural additive). In this study, we investigated the optimization of the experimental design of carboxymethyl cellulose/hydromagnesite stromatolite (CMC/HS) bio-nanocomposites using a green and one-step sonochemical method at room temperature. In addition, we constructed a mathematical model which relates the intrinsic viscosity with all operating variables, and we carried out statistical error analysis to assess the validity of the proposed model. The characterization and chemical functional groups of CMC/HS bio-nanocomposites were determined by different advanced techniques such as SEM, HRTEM, DLS, FTIR, XRD, and BET. The challenge test was used to show the preservative efficacy of CMC/HS bio-nanocomposites against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Aspergillus brasiliensis. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltrazolium bromide (MTT) assay was performed on L929 cells to evaluate the in vitro cytotoxicity of CMC/HS bio-nanocomposites. According to the results, we showed that the synthesized CMC/HS bio-nanocomposites have no cytototoxic effects on L929 fibroblast cells and could be considered to be an alternative green nano-additive preservative against pathogenic microorganisms.
ABSTRACT
The COVID-19 pandemic has influenced the demand for products that are considered hygienic, thereby increasing the production rate and variety of hygienic products. Researching new antimicrobial materials is gaining importance with increasing awareness of the topic of infectious diseases caused by various microorganisms. In the present work, cellulosic handsheets were produced and then coated with coatings having different glutaraldehyde concentrations by a roller bar technique. The surface water absorption capacity of the sample groups and their structural and strength characteristics were analyzed. Also, the cross-linking effect of glutaraldehyde was determined by FTIR analysis. The results not only showed that, after being exposed to glutaraldehyde on their surface, the handsheets presented a higher hydrophilic structure and higher tensile strength properties, but also confirmed that coatings containing 1-5% glutaraldehyde lessened fungal activity on their surfaces.
ABSTRACT
Advancements in polymer science and engineering have helped the scientific community to shift its attention towards the use of environmentally benign materials for reducing the environmental impact of conventional synthetic plastics. Biopolymers are environmentally benign, chemically versatile, sustainable, biocompatible, biodegradable, inherently functional, and ecofriendly materials that exhibit tremendous potential for a wide range of applications including food, electronics, agriculture, textile, biomedical, and cosmetics. This review also inspires the researchers toward more consumption of biopolymer-based composite materials as an alternative to synthetic composite materials. Herein, an overview of the latest knowledge of different natural- and synthetic-based biodegradable polymers and their fiber-reinforced composites is presented. The review discusses different degradation mechanisms of biopolymer-based composites as well as their sustainability aspects. This review also elucidates current challenges, future opportunities, and emerging applications of biopolymeric sustainable composites in numerous engineering fields. Finally, this review proposes biopolymeric sustainable materials as a propitious solution to the contemporary environmental crisis. © 2022 Elsevier Ltd.
ABSTRACT
This paper promotes a basic, quick, stature adaptable, and direct approach to selecting exceptionally suitable materials in polyethylene glycol diacrylate (PEGDA) and silicon for microneedle fabrication. Researchers and scientists are facing challenges in readily selecting biocompatible materials for microneedle fabrication. Solid porous silicon and PEGDA microneedles are particularly biocompatible and desirable for vaccine delivery by the transdermal vaccine delivery method if microneedle arrays are fabricated successfully using lithography techniques as they belong to enhanced patient concurrence and well-being. Moreover, silicon and PEGDA microneedles are the ultimate for conveying coronavirus vaccines. In this work, we applied the ANSYS workbench tool to investigate the properties of triangular pyramidal-shaped solid silicon and PEGDA microneedle array to perform structural analysis on microneedle for estimating the capability of an array of needles to enter and convey vaccines along with the skin. These outcomes demonstrated that microneedles of porous silicon are better than polymers such as PEGDA as far as mechanical strength and capacity to convey drugs. Buckling was anticipated as the fundamental method to estimate the failure of microneedles and finally, by analysis, it was clear that buckling does not impact the potential of the silicon microneedle needle array. Silicon and PEGDA microneedles are penetrated against human skin surfaces in explicit dynamics by utilizing the ANSYS tool to select the best material. Along these lines, the current strategy can work with silicon and PEGDA microneedles for useful applications. The von Mises stresses generated by applying loads on silicon and PEGDA arrays were greater than the skin resistance of 3.18 MPa and suitable for skin insertion. Silicon microneedles are sustained due to buckling but PEGDA needles fail if the loading is more than 0.1 N. Vaccination can be provided to humans if needle arrays are fabricated based on this approach and design analysis and considering parameters.
ABSTRACT
Synthesis of bio-based environmental remedial and antimicrobial products is an urgent need of the 21st century in the COVID-19 pandemic world. Keeping this in mind, cellulose-supported Ag bionanocomposites (AGC NCs) were synthesized by using cellulose as a reducing and stabilizing agent. AGC NCs showed potential antimicrobial activity against Candida albicans, Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, and Bacillus subtilis with a MIC of 15, 15, 35, 15, and 30 mu g ml(-1) respectively. AGC NCs efficiently degraded harmful dyes, Orange G, Phenol red, Brilliant blue FCF, Giemsa stain, Neutral red, and 2-nitro aniline in the presence of sunlight with a rate constant of 0.229 x 10(-2) min(-1), 1.147 x 10(-2) L mol(-1) min(-1), 0.447 x 10(-2) L mol(-1) min(-1), 4.144 x 10(-2) mol L-1 min(-1), 0.317 x 10(-2) L mol(-1) min(-1), and 0.785 x 10(-2) L mol(-1) min(-1) in 60 min respectively. AGC NCs also showed efficient antioxidant activity in DPPH assay with an IC50 value of 52.67 mu g ml(-1). Formation of Ag NPs was confirmed by observing the UV-Visible absorption peak at 418 nm. The FCC structure of AGC NCs was confirmed by the X-ray diffraction (XRD) pattern with well-defined peaks at angles 38.24 degrees, 44.40 degrees, 64.64 degrees, and 77.28 degrees corresponding to the planes 111, 200, 220, and 311, with a d-spacing of 2.35, 2.04, 1.44, and 1.23 (JCPDS no. 00-001-1164). The presence of cellulose in AGC NCs was determined by Fourier transform infrared spectroscopy (FTIR) with bands at 3421.90 cm(-1) and 2899.3 cm(-1) due to O-H stretching and the methylene (-CH2-) group respectively and at 1076-1023 cm(-1) and 903 cm(-1) due to -C-O-C- pyranose ring skeletal vibration and beta-glycosidic linkages. The morphology, shape and size (13.21 nm), and elemental composition of the nanocomposites were determined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS) respectively. The thermal properties (exothermic peaks appear at 335 degrees C and 440 degrees C due to the thermal degradation of Ag NPs and cellulose respectively), surface area (13.892 m(2) g(-1)), stability (-18.43 +/- 0.850 mV), and hydrodynamic diameter (399.10 +/- 30.49 nm) and polydispersity index (PDI) value (0.565 +/- 0.193) of the composites were determined by thermogravimetric analysis (TGA) and differential thermal analysis (DTA), Brunauer-Emmett-Teller (BET) method, Zeta potential studies, and dynamic light scattering (DLS) respectively.