Currently most of the aerogel-based drug delivery carriers are made from non-biodegradable materials, such as silica. In this study, highly porous cellulose aerogels with Brunauer-Emmett-Teller (BET) ...surface areas that varied between 22 m2 g-1 and 525 m2 g-1 were prepared from a sugarcane bagasse cellulose solution of various concentrations. The potential utility of cellulose aerogels as controlled release carriers was evaluated by loading methylene blue (MB) as a model hydrophilic drug. The MB loading capacity and release kinetic profiles of cellulose aerogels were observed to be substantially influenced by their BET surface areas. Under optimum conditions, a maximum loading capacity of 6.4 mg MB mg-1 cellulose aerogel was achieved with sustained release of MB from cellulose aerogels at physiological pH over a period of 23 h.
Fluorescein 5(6)-isothiocyanate starch maleate (FISM) nanoparticles were prepared by covalently attached fluorescein 5(6)-isothiocyanate (FITC) with starch maleate. FISM nanoparticles with a mean ...particle size of 87 nm were formed via self-assembly upon precipitation in ethanolic solution. FISM nanoparticles were strongly fluorescent with maximum emission wavelength of 518 nm. The fluorescence of FISM nanoparticles can be quenched by silver (Ag+) and lead (Pb2+) ions in a concentration dependent manner. We have demonstrated the first use of FISM nanoparticles as cheap and effective fluorescent sensing probes for Ag+ and Pb2+ ions with detection limits as low as 2.55 × 10−5 M and 3.64 × 10−5 M, respectively.
Recent trends in electrochemical sensors based on conducting polymer functionalized graphene for the detection of pollutants in water are highlighted in this review. Graphene has been the subject of ...a lot of scientific research to be composited with conducting polymers. Researchers are interested in graphene and its variants because they have a lot of good qualities, like good electrical and mechanical properties and very high surface area. With this review, we intend to arouse interest in the important topic of graphene and conducting polymer nanocomposite that is making significant advances in electrochemical sensing, especially for sensing pollutants in water.
Hydrophobic, magnetic and highly porous cellulose aerogel was prepared by a simple method for fast and selective absorption of oil from water surface. The aerogel was able to absorb oil up to about ...28 times of its own weight within 10min and could be easily removed and recovered from the water surface by an external magnet. It could be either reused after washing with ethanol, or incinerated with the absorbed oil. The potential application of cellulose aerogel as an oil absorbent was demonstrated by its ease of preparation, low cost of precursor materials, magnetically retrievability, as well as high oil absorption capacity and efficiency.
•Hydrophobic cellulose aerogel was prepared for oil absorption application.•Magnetic nanoparticles were incorporated into the aerogel to impart magnetic property.•The hydrophobic and magnetic aerogel exhibited high oil absorption capacity.
In the present study, natural deep eutectic solvent composed of choline chloride and ascorbic acid (CHCL/AA NADES) was formulated for enhancing the solubility and antioxidant properties of ...antioxidant extracts from fruit wastes of Mangifera pajang. The solubilities of Mangifera pajang's antioxidant extracts in water and CHCL/AA NADES at different water contents (0–50 wt%) were investigated. It was observed that the antioxidant extracts were most soluble in the CHCL/AA NADES with 10 wt% of water, and the concentration of antioxidant was found to be approximately 15% and 4% as compared to water and pure CHCL/AA NADES, respectively. The positive effect of water on NADES can be related to the reduced viscosity of NADES, where the viscosity decreased up to 74% upon addition of water. Aside from that, all the tested CHCL/AA NADES enhanced the antioxidant capacity of antioxidant extracts by 1.3–14.64% compared to the antioxidant extracts in water. This finding highlights the role of CHCL/AA NADES as an antioxidant capacity enhancer. Noteworthy, the antioxidant extracts solubilized in the CHCL/AA NADES system formed a nano-scale cluster structure, as depicted by the TEM image, suggesting that the CHCL/AA NADES could potentially use in nanoformulation that provides protection to the antioxidant extracts.
•CHCL/AA NADES was formulated for enhancing the solubility and antioxidant capacity.•Addition of water into CHCL/AA NADES enhances the solubility of antioxidant by 15%.•CHCL/AA NADES further increased the DPPH scavenging activity.•The antioxidants-CHCL/AA NADES formed nano-scale cluster structure.
•We synthesized C-dots from sago wastes via one-step pyrolysis method.•The pyrolysis temperature of carbonisation was optimized.•Physicochemical and optical properties of the synthesized C-dots were ...investigated.•Fluorescence quenching of C-dots was observed in the presence of various metal ions.•We suggested the use of C-dots as potential probe for metal ions sensing.
This work reports the synthesis of carbon dots (C-dots) from sago industrial waste using thermal pyrolysis approach. The pyrolysis condition was found to govern the carbonisation conversion of bulk sago waste into carbon rich residue that can be further isolated to obtain carbon dots. In order to obtain the best yield of the carbon dots, optimization of the thermal pyrolysis conditions have been performed which consisted of varying temperature of carbonisation at a constant heating duration. The C-dots can be dispersed in aqueous media and portrayed a significant fluorescent property that can be observed by naked eye under a UV light source. The optimum temperature of carbonisation was determined at 400°C in which the strongest fluorescence emission was record at 390nm with the optimum excitation wavelength of 315nm. The fluorescence of the C-dots was found to be significantly quenched in the presence of various metal ions. Thus, the C-dots can be adopted as a potential optical probe for sensing of metal ions in aqueous media. An analytical characterization has been performed in this study over a series of commonly available metal ions and the sensing characteristics were evaluated using the standard Stern–Volmer quenching model. This study has successfully demonstrated an innovative approach of converting agricultural waste into high value optical sensing receptors for metal ions detection.
The study compared the antibacterial activity of synthesized ZnO nanoparticles (NPs) from fresh leaf and fresh stem bark aqueous extracts of Carica papaya against five selected microbes: ...Staphylococcus aureus, (Gram positive (+ve)), Escherichia coli (Gram negative (–ve)), Acinetobacter baumanni (Gram–ve), Exiguobacterium aquaticum (Gram+ve), and Klebsielia pneumonia (Gram +ve). The morphological features of the biosynthesized ZnO NPs were analyzed using transmission electron microscope (TEM) and scanning electron microscope (SEM); the Fourier-transform infrared spectrometer (FTIR) technique was used to observe the surface functional groups. The experimental results indicated that ZnO NPs were successfully synthesized using modified hydrothermal technique, which showed agglomerated flake-like or petal-like shapes with the organic extract surrounding the formed particles. The average particle size of the synthesized ZnO nanoparticles determined by SEM ranged between 54-97 nm with the width and length of the petal-like structures been 30 nm and 62 nm respectively. The average ZnO NPs from fresh stem bark extract of Carica papaya with higher concentrations (100-1000 ppm) demonstrated a higher antibacterial activity than the fresh leaf extracts. On the other hand, ZnO NPs from fresh leaf extracts of lower concentrations (25-50 ppm) rather showed a suitable result than the fresh stem bark. In general, ZnO NPs showed a positive antibacterial result towards the selected microbes. This shows that, the synthesized ZnO NP can be a substitute to chemical methods.
Stable colloidal suspension of magnetite/starch nanocomposite was prepared by a facile and aqueous-based chemical precipitation method, Magnetite/carbon nanocomposite thin films were subsequently ...formed upon carbonization of the starch component by heat treatment under controlled conditions. The initial content of native sago starch as the carbon source was found to affect the microstructure and electrochemical properties of the resulted magnetite/carbon nanocomposite thin films, A specific capacitance of 124 F/g was achieved for the magnetite/carbon nanocomposite thin films as compared to that of 82 F/g for pure magnetite thin films in Na2SO4 aqueous electrolyte.
Sago starch (Metroxylan sago) modified with polyvinyl alcohol (PVA) incorporated with citric acid as an antimicrobial agent at the optimized ratio of 5:8:15 (%, w v–1) for starch: PVA: citric acid is ...synthesized. The starch‐citrate film presents antimicrobial activity against the pathogenic food borne bacteria Salmonella thypimurium (S. thypimurium), Escherichia coli (E. coli) (O157:H7), and Listeria monocytogenes (L. monocytogenes) and food fungus Aspergillus spp. and Rhizopus spp. The studies showed that 98–99% of food borne bacteria growth and 87–99% of fungal growth can be inhibited. Qualitative assessment of food shelf‐life reveals that the starch‐citrate film is more efficient to inhibit the microbial growth in cake and bread samples compared to commercial food wrappers, as the film can extend the shelf‐life of the food products (10 days for cake and 40 days for bread). The potential application of this starch‐citrate film as antimicrobial and eco‐friendly bio‐based food packaging application is therefore demonstrated.
A homogeneous and translucent antimicrobial starch‐based is prepared from sago starch. It can be used for antimicrobial packaging to extend the shelf‐life of bakery products.
Nanostructured multilayer manganese dioxide/nickel/copper sulfide (MnO2/Ni/CuS) composite films were successfully deposited onto supporting polyethylene terephthalate (PET) substrate through the ...sequential deposition of CuS, Ni, and MnO2 thin films by chemical bath deposition, electrodeposition, and horizontal submersion deposition techniques, respectively. Deposition of each thin-film layer was optimized by varying deposition parameters and conditions associated with specific deposition technique. Both CuS and Ni thin films were optimized for their electrical conductivity whereas MnO2 thin film was optimized for its microstructure and charge capacity. The electrochemical properties of nanostructured multilayer MnO2/Ni/CuS composite films were evaluated by cyclic voltammetry as electrode materials of an electrochemical capacitor prototype in a dual-planar device configuration. Cyclic voltammogram in mild Na2SO4 aqueous electrolyte exhibited a featureless and almost rectangular shape which was indicative of the ideal capacitive behavior and high cycling reversibility of the electrochemical capacitor prototype. Nanostructured multilayer MnO2/Ni/CuS composite films on supporting polyethylene terephthalate (PET) substrate could potentially be utilized as electrode materials for the fabrication of high performance electrochemical capacitors.
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