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Jun 2023
The increasing demand for environmentally-friendly materials has led to a surge in research on the production of biodegradable polymers. In this study, we investigate the synthesis of a biodegradable polymer by graft copolymerization of gum Arabic (GA) and polyethylene glycol (PEG). GA, a natural polysaccharide and PEG, a synthetic water-soluble polymer, were used as the backbone and graft monomer, respectively. The graft copolymerization was carried out using benzoyl peroxide as an initiator and performed under nitrogen atmosphere. The resulting polymer was characterized by Fourier transform infrared (FTIR) spectroscopy, Xray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The FTIR spectra confirmed the formation of the graft copolymer, and TGA analysis showed that the copolymer had higher thermal stability than GA. The DTA thermograms indicated two thermal events. The evaporation of water and organic polyethylene glycol components was measured, and the first mass loss was due to the loss of adsorbed and structural water in the gum Arabic, which occurred between 31.87 and 180°C, while the second, corresponding to the pyrolysis of polyethylene glycol functional groups and polysaccharide decomposition, resulted in a 70% mass loss. SEM morphological analysis of gum Arabic showed aggregates of high irregularity in particle shape. The cracks and holes obtained in the Gum Arabic micrograph disappeared from the new gum Arabic-graft-polyethylene glycol, leaving a smooth surface with scattered particles in the image, which was due to the grafting copolymer. From the XRD patterns, the percentages of the amorphous and crystalline phases were determined. The results show that gum Arabic has a 78% degree of crystallinity, whereas gum Arabic-graft-polyethylene glycol has the lowest value of 51%. Biodegradation activity was observed using the fungus Aspergillus flavus on different days on gum Arabic-g-polyethylene glycol. The results clearly showed inhibition zones with a change in the state of the copolymer from solid to liquid from days 8 to 14. These results indicate that the GA-PEG copolymer has potential as a biodegradable material for use in various applications, such as packaging, agriculture, and medical industries.
Oct 2019 DOI 10.14302/issn.2689-4602.jes-19-2760
The environmental impacts of waste disposal of polyethylene bags and seasonal variation of polyethylene disposal in Gusau City of Zamfara state, Nigeria was investigated. General public waste disposals from homes, schools and daily markets, were randomly selected for data collection. The data showed that polyethylene waste is generated more in the dry season than the wet season. The result also showed that table water sachet has 75% disposal. This is because, sachet water is cheap and consumed throughout the year with very little seasonal variation while at homes and markets also, displayed a very interesting pattern. The study revealed that in the market, polyethylene for table water sachets (10%) was the least, followed by ice cream sachets (6%), assorted items (5%) and biscuits wrappers (4%). On the other hand, the results showed that, at home, polyethylene for assorted items was the highest (61%), closely followed by biscuit wrappers (20%), table water sachets (14%) and ice cream wrappers (5%) respectively. Polyethylene waste poses various threats to public health and adversely affects flora and fauna as well as the environment especially when it is not appropriately collected and properly disposed. And based on this research, it was found that most of the public do not know the advantages, disadvantages and the health effects of rampant and improper disposal of polyethylene bags. It is concluded that aggressive campaign and enlightenment of the masses on the threats posed by polyethylene bags pollution should be carried out to prevent further negative environmental impact.
Sep 2020 DOI 10.14302/issn.2835-513X.ijl-20-3454
We investigated physical steric and thermal stability effects induced by cholesterol and polyethylene glycol (PEG) in liposomes encapsulated with riboflavin. The composition of liposome was varied systematically to decipher the individual and combined effects of cholesterol and PEG on the stabilization of liposomes, specially the photopolymerizable liposomes for their potential applications in photo-treatments. Our results indicate that inclusion of PEG in the lipids enhances the steric stabilization by adopting a brush-like regime that prevents the agglomeration of encapsulated liposomes. A mechanistic differential scanning calorimetry studies reveal the phase transitions and enthalpy changes in the lipid bilayer due to the presence of cholesterol suggesting its role in regulating membrane fluidity. Supporting in- vitro studies confirm the efficacy of PEGylated formulations encapsulating riboflavin.
Aug 2019 DOI 10.14302/issn.2690-0904.ijoe-19-2985
Hairdressers are taught to use gloves when dyeing hair. We wanted to study what gloves are recommendable for other common hair dye substances than p-phenylenediamine, such as toluene-2,5-diamine sulphate and 2‐methoxymethyl‐p‐phenylenediamine. The gloves used in professional salons and the gloves commonly sold with hair dyes for home-use were investigated. 7 volunteers previously allergic to toluene-2,5-diamine sulphate and p-phenylenediamine were tested in vivo with an open chamber test system to examine the permeation of chemicals through gloves (vinyl, nitrile and polyethylene), mimicking the real use condition of permanent hair dyes. The nitrile gloves used gave excellent protection with all four hair dyes tested. A good capacity of protection was found with the polyethylene glove, supplied with the package of a home-use hair dye, when tested with the same hair dye. The advice to hairdressers is to choice nitrile gloves when using the permanent hair dyes currently available on the market.
Apr 2019 DOI 10.14302/issn.2644-0105.jbfb-19-2681
This study compared the effect of container material type on macronutrient changes in human breast milk (HBM) during frozen storage. HBM was collected from breastfeeding mothers and baseline macronutrients were analyzed and recorded. The HBM was aliquoted into milk storage containers of five commonly used materials (low-density polyethylene (LDPE), polypropylene (PP), glass, stainless steel, and silicone). The samples were frozen in a standard freezer (-20°F) for 30, 60, and 180 days prior to thawing and retesting macronutrient values. In the 155 samples analyzed, macronutrient changes among different types of storage materials were insignificant at 30 and 60 days of frozen storage. When comparing macronutrients at baseline to 180 days, there was a significant decrease in protein value over time in LDPE containers as compared to silicone containers (p=0.001). Likewise, there was a significant decrease in total calories from baseline to 180 days in both PP and LDPE containers compared to silicone (p=0.046 and 0.013, respectively). While not significant for short-term storage, HBM has losses of macronutrients (protein) with long-term storage in LDPE and PP plastics. These differences could have major nutritional impact on growth, particularly to infants born prematurely.
Jan 2014 DOI 10.14302/issn.2328-0182.japst-12-183
Gold nanorods (GNRs) are plasmonic nanostructures by virtue of their size-dependent optical properties, offer a bionanotechnology platform in areas of bioimaging, drug delivery etc for disease diagnosis, prognosis, and therapy. GNRs are more sensitive to changes in local environments, and offer strong scattering and absorption efficiencies thus providing opportunities to integrate multiple imaging modes and therapeutic strategies. The hydrodynamic size of these GNR under physiological condition is <100 nm, making them ideal as intracellular delivery agents. RNA interference using small inhibitory RNA (siRNA) has become a powerful tool to downregulate mRNA levels by cellular nucleases that become activated when a sequence homology between the siRNA and a respective mRNA molecule is detected. siRNA is used to silence genes involved in the pathogenesis of various diseases and holds a promising option for the development of novel therapeutic strategies in neurological dysregulation such as that observed in drug addiction. However, a major challenge in gene therapy continues to be effective delivery of siRNA and its sustained release at targeted sites. Previously, we have shown the GNR coated with poly (diallyldimethyl ammoniumchloride) (GNR-PDDAC) electrostatically complexed to the dopamine- and cAMP-regulated neuronal phosphoprotein (DARPP-32) siRNA forming a GNR-nanoplex that was able to effectively silence the DARPP-32 gene expression in dopaminergic neuronal (DAN) cell cultures in- vitro. The current report, explores if modification of the surface coating properties of the GNRs with different surface coatings namely, amino terminated polyethylene glycol (GNR-PEG), polyethyleneimine (GNR-PEI) and Chitosan (GNR-CIT) alters their stability, cytotoxicity and DARPP-32 gene silencing efficiency in-vitro dopaminergic neuronal (DAN) cell cultures with the goal of determining the most suitable surface coating for the GNR that would provide a GNR-nanoplex with the most stability, least cytotoxicity and most efficacious gene silencing.