Electrospun poly (Ɛ-caprolactone)-eggshell membrane nanofibrous mat as a potential wound dressing material

Eggshell membrane (ESM) is a highly-collagenized, biopolymeric fibrous network generally considered domestic and industrial waste. However, its inherent extraordinary properties have made ESM widely used in different fields due to its high potential applications, especially in the biomedical field. In this study, a poly (?-caprolactone) (PCL) integrated ESM (PCL/ESM) nanofibrous mat is fabricated using an electrospinning technique to produce wound dressing materials with enhanced biocompatibility and antibacterial efficacy for potent tissue regeneration. The physicochemical, biological, and mechanical properties of the electrospun fabricated nanofibrous mat PCL (15% w/v) and PCL/ESM (0.5% w/v, 1.5% w/v, and 2.5% w/v) were investigated using FE-SEM, ATR-FTIR, DSC, and XRD. In addition, the water uptake ability, degradability, cell viability, and antibacterial activity of the mats were evaluated. The FTIR results revealed that the molecular interactions of ESM with the PCL are through hydrogen bond formation. The morphology and the nanofiber dimension of the electrospun fabricated mat are within the collagen dimensions present in the extracellular matrix. The overall results confirm that the PCL/ESM (2.5% w/v) have shown the most excellent mechanical properties with high biocompatibility and efficient antibacterial activity among the other fabricated mat. Therefore, this study suggests that electrospun PCL/ESM mat could be a potential material for wound dressing

Determination of para-arsanilic acid with improved diazotization reaction using differential pulse cathodic stripping voltammetry in aqueous system

Para-arsanilic acid (p-ASA) has been widely used in the poultry industry to promote growth and prevent dysentery. It is excreted unchanged in the manure and released into non-target sites causing organoarsenic pollution risk to the environment and living system. Therefore, simple and effective analytical strategies are demanded for determining the samples that contain p-ASA. However, direct determination of both p-ASA and ortho-arsanilic acid (o-ASA) using differential pulse cathodic stripping voltammetry (DPCSV) gives the similar voltammograms that directly hamper the analysis used by the DPCSV technique. In this study, a method to determine and differentiate p-ASA from o-ASA via diazotization and coupling reaction of the amine groups followed by the direct DPCSV determination of diazo compounds is presented. The diazotization reaction carried out at pH 1.5 and 0 ± 1°C for 10 min showed two reduction peaks in DPCSV at-70 mV and -440 mV vs. Ag/AgCl (KCl 3 M). However, when the diazotization reaction was performed at pH 12.5 and 0 ± 1°C for 40 min, a coloured azo compound was produced and the DPCSV showed only one reduction peak that appeared at -600 mV vs. Ag/AgCl (3 M of KCl). The results of this study show that only p-ASA compound gave a reduction peak, whereas o-ASA compound did not give any peak. The detection limit of p-ASA was found to be 4 × 10(-8 )M. As a result, the proposed electro-analytical technique might be a good candidate to determine and differentiate the p-ASA present in the poultry and environmental samples

Modified oil palm industry solid waste as a potential adsorbent for lead removal

As one of the largest oil palm producers in the world, Malaysia also produces the most abundant residues of palm oil known as empty fruit bunch (EFB). Mismanaging of this residue such as being unused and disposed to sanitary landfills will put the environments in danger. Hence, modification and environmental application of EFB for the pollutant removal is a hot research topic in recent trend. This study involves modification of palm oil industrial residues as EFB-activated carbon and further used as an adsorbent for the removal of lead. The physicochemical property of the EFB-activated carbon was assessed using SEM, FTIR and BET. The adsorption conditions i.e., pH, adsorbent dose, and contact time for the effective removal of lead were optimized. The optimum reaction conditions for lead adsorption by the EFB-activated carbon were 10 g/L of adsorbent, pH 1.0 and 15 min as contact time for the effective removal of lead in aqueous solution. The maximum lead concentration that has removed successfully was 92.24 mg/L under the optimum condition. This study may provide solution to manage the EFB residuals generated from palm oil industries and lead contaminated in the aquatic environment

PVDF-ErGO-GRC electrode: a single setup electrochemical system for separation, pre-concentration and detection of lead ions in complex aqueous samples

An effective electrode was developed based on electromembrane extraction (EME) and square wave voltammetry (SWV) for simultaneous separation, pre-concentration and determination of lead (II) (Pb(II)) ions in complex aqueous samples. Electrochemically reduced graphene oxide-graphite reinforced carbon (ErGO-GRC) was utilized in conjunction with the SWV. Pb(II) ions were extracted from an aqueous sample solution into an acidic acceptor phase (1 M HCl) in the lumen of the polyvinylidene fluoride (PVDF) membrane bag by the application of voltage of maximum 6 V across the supported liquid membrane (SLM), consisting of organic solvent and di-(2-ethylhexyl)phosphoric acid (D2EHPA). The parameters affecting the EME were optimized for Pb(II) ions. The optimum EME conditions were found to be 20% D2EHPA in 1-octanol impregnated in the wall of PVDF membrane (PVDF17) as the SLM, extraction time of 20 min, pH of sample solution of 8 and a voltage of 5 V. The PVDF-ErGO-GRC electrode system attained enrichment factors of 40 times and 80% of extraction with relative standard deviations (n=5) of 8.3%. Good linearity ranging from 0.25 to 2 nM with coefficients correlation of 0.999 was obtained. The Pb(II) ions detection limit of PVDF-ErGO-GRC electrode was found to be 0.09 nM. The newly developed single setup electrochemical system was applied to complex aqueous samples such as tap, river and sea water to evaluate the feasibility of the method for applications

A sensitive, selective and rapid determination of lead(II) ions in real-life samples using an electrochemically reduced graphene oxide-graphite reinforced carbon electrode

In this study, a sensitive and cost-effective electrochemically reduced graphene oxide (ErGO) on graphite reinforced carbon (GRC) was developed for the detection of lead (Pb(II)) ions present in the real-life samples. A film of graphene oxide (GO) was drop-casted on GRC and their electrochemical properties were investigated using cyclic voltammetry (CV), amperometry and square wave voltammetry (SWV). Factors influencing the detection of Pb(II) ions, such as grades of CRC, constant applied cathodic potential (CACP), concentration of hydrochloric acid and drop-casting drying time were optimised. GO is irreversibly reduced in the range of -0.7 V to -1.6 V vs Ag/AgCl (3 M) in acidic condition. The results showed that the reduction behaviour of CO contributed to the high sensitivity of Pb(II) ions detection even at nanomolar level. The ErGO-CRC showed the detection limit of 0.5 nM and linear range of 315 nM in HCl (1 M). The developed electrode has potential to be a good candidate for the determination of Pb(II) ions in different aqueous system. The proposed method gives a good recovery rate of Pb(II) ions in real-life water samples such as tap water and river water

Metabolites characterisation of laccase mediated Reactive Black 5 biodegradation by fast growing ascomycete fungus Trichoderma atroviride F03

In this study, fast growing ascomycete fungus Trichoderma atroviride F03 was explored to biodegrade bis-azo dye, Reactive Black 5 (RB5). The maximum RB5 biodegradation (91.1%) was achieved in the culture medium supplemented with an appropriate carbon source (glucose, 20gl-1), and nitrogen source (yeast extract, 20gl-1) at pH 5 and 27°C. The laccase produced by T.atroviride F03 was involved in the RB5 biodegradation processes. The metabolites such as (I) 1,2,4-trimethylbenzene, (II) 2,4-ditertbutylphenol, and (III) benzoic acid-TMS) were identified as the biodegradation products of RB5 using gas chromatography-mass spectrometry (GC-MS). The presence of these metabolites suggested that RB5 biodegradation was initiated by the cleavage of azo bond forming naphthalene-1,2,8-triol and sulphuric acid mono-[2-(toluene-4-sulfonyl)-ethyl] ester. The sulphuric acid mono-[2-(toluene-4-sulfonyl)-ethyl] ester was further desulphonated to 1,2,4-trimethylbenzene. Then, the oxygenated ring of C1 and C2 naphthalene-1,2,8-triol was cleaved to 2-(2-carboxy-ethyl)-6-hydroxy-benzoic acid. The degradation of 2-(2-carboxy-ethyl)-6-hydroxy-benzoic acid could be proceeded with two pathways: (i) decarboxylation and methylation to form 2,4-ditertbutylphenol and (ii) decarboxylation mechanism that induced the formation of benzoic acid-TMS. Finally, this study proved that T.atroviride F03 might be a good candidate in treating textile effluent containing azo dye as this treatment does not generating aromatic amines

Phyto-synthesis of silver nanoparticles using Alternanthera tenella leaf extract: an effective inhibitor for the migration of human breast adenocarcinoma (MCF-7) cells

In this study, phyto-synthesis of silver nanoparticles (AgNPs) was achieved using an aqueous leaf extract of Alternanthera tenella. The phytochemical screening results revealed that flavonoids are responsible for the AgNPs formation. The AgNPs were characterised using UV-visible spectrophotometer, field emission scanning microscopy/energy dispersive X-ray, transmission electron microscopy, fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction. The average size of the nanoparticles was found to be ≈48 nm. The EDX results show that strong signals were observed for the silver atoms. The strong band appearing at 1601-1595 cm-1 correspond to C-C stretching vibration from dienes in FT-IR spectrum indicating the formation of AgNPs. Human breast adenocarcinoma (MCF-7) cells treated with various concentrations of AgNPs showed a dose-dependent increase in cell inhibition. The IC50 value of the AgNPs was calculated to be 42.5 μg mL-1. The AgNPs showed a significant reduction in the migration of MCF-7 cells

Heavy metal pollution in immobile and mobile components of lentic ecosystems—a review

With growing population and urbanization, there is an increasing exploitation of natural resources, and this often results to environmental pollution. In this review, the levels of heavy metal in lentic compartments (water, sediment, fishes, and aquatic plants) over the past two decades (1997–2017) have been summarized to evaluate the current pollution status of this ecosystem. In all the compartments, the heavy metals dominated are zinc followed by iron. The major reason could be area mineralogy and lithogenic sources. Enormous quantity of metals like iron in estuarine sediment is a very natural incident due to the permanently reducing condition of organic substances. Contamination of cadmium, lead, and chromium was closely associated with anthropogenic origin. In addition, surrounding land use and atmospheric deposition could have been responsible for substantial pollution. The accumulation of heavy metals in fishes and aquatic plants is the result of time-dependent deposition in lentic ecosystems. Moreover, various potential risk assessment methods for heavy metals were discussed. This review concludes that natural phenomena dominate the accumulation of essential heavy metals in lentic ecosystems compared to anthropogenic sources. Amongst other recent reviews on heavy metals from other parts of the world, the present review is executed in such a way that it explains the presence of heavy metals not only in water environment, but also in the whole of the lentic system comprising sediment, fishes, and aquatic plants

Exploration of fast growing botryococcus sudeticus for upstream and downstream process in sustainable biofuels production

This study explores an integrated approach on biodiesel and bioethanol production from the indigenous strain Botryococcus sudeticus. The alga was isolated from the freshwater pond and mass cultivated in 25 m2 open raceway pond. A two-step combined harvesting technique such as coagulation and flocculation was standardized. The results showed that 150 ppm of ferric chloride and 15 ppm of organic polymer Poly-(D) glucosamine increases the harvesting efficiency and the biomass yield was achieved up to 99%. Based on the areal and volumetric biomass productivity, it is estimated that the alga B. sudeticus can produce 71.1 t ha-1 y-1 of dry biomass. The dry biomass was analyzed for its chemical compositions. The results revealed that, the alga accumulates 4.5% of hydrocarbon, 22.6% of lipid, 23% of carbohydrate and 19.5% of protein, respectively. Sequential stages of esterification and then transesterification were studied to convert the FFA and triglycerides into biodiesel. Triacylglycerides and free fatty acids were converted to alkyl esters with up to 89% efficiency and the biodiesel yield was estimated up to 0.195 g/dry biomass. Further, the exploitation of lipid extracted residual biomass was explored for bioethanol production. The results indicate that 0.165 g bioethanol/g residual biomass was obtained at 30 °C fermentation for 168 h

Persistence, toxicological effect and ecological issues of endosulfan – A review

Endosulfan, an organochlorine pesticide, is categorized as persistent organic pollutants (POPs) in the Stockholm Convention and phased out globally. In this review, the distribution, toxicity, and interactive effect of endosulfan isomers and their remediation approaches are discussed. The occurrence of endosulfan residues in various environmental compartments (air, soil, and water) and biota (plants and animals) reported during 2016–2020 confirms its persistence and biomagnification probability in the ecosystem. The distribution pattern of endosulfan residues in the ecosystem is indicating both historical and recent input of endosulfan in the farmland. The existing literature on the ecotoxicological effects of endosulfan highlights various negative impacts on the non-targeted species, including plants, algae, aquatic species, terrestrial organisms, and mammals, including humans. Significantly, the toxicity of endosulfan could increase its intensity while interacting with other coexisting chemicals. Finally, this review suggests the distribution and persistence of endosulfan residues in the ecosystem could pose a potential risk to living organisms, including humans