We have demonstrated the loading of curcumin onto starch maleate (SM) under mild conditions by mixing dissolved curcumin and SM nanoparticles separately in absolute ethanol and ethanol/aqueous (40 : ...60 v/v), respectively. Curcumin-loaded starch-maleate (CurSM) nanoparticles were subsequently precipitated from a homogeneous mixture of these solutions in absolute ethanol based on the solvent exchange method. TEM analysis indicated that the diameters of CurSM nanoparticles were ranged between 30 nm and 110 nm with a mean diameter of 50 nm. The curcumin loading capacity of SM as a function of loading duration was investigated using the UV-visible spectrophotometer. The loading of curcumin onto SM increased rapidly initially with loading duration, and the curcumin loading capacity of 15 mg/g was reached within 12 hours. CurSM nanoparticles exhibited substantially higher water solubility of 6.0 × 10−2 mg/mL which is about 300 times higher than that of pure curcumin. With enhanced water solubility and bioaccessibility of curcumin, the potential utility of CurSM nanoparticles in various biomedical applications is therefore envisaged.
Spherical cellulose beads with tailored mean diameter between micrometer (20–80 μm) and nanometer (40–200 nm) ranges were fabricated from regenerated cellulose of paper wastes via water-in-oil (W/O) ...microemulsion and nanoprecipitation processes, respectively. The mean diameter ranges of cellulose beads were precisely controlled via modulating fabrication parameters such as stirring speed, surfactant concentration, cellulose concentration, and reaction temperature. By tailoring their mean diameter ranges and using curcumin as a model drug, cellulose beads with enhanced loading capacities and optimized release kinetic profiles of curcumin were fabricated.
Various types of lignocellulosic biomass wastes (LBW) had been successfully converted into cello-oligomers with different chain lengths via a controlled depolymerization process. Cellulose fibres ...isolated from LBW samples were dissolved with room temperature ionic liquid (RTIL) in the presence of an acid catalyst, Amberlyst 15 DRY. The effects of reaction time on the degree of polymerization and yields of water-insoluble cello-oligomers formed were studied. Besides, the yields of water-soluble cello-oligomers such as glucose and xylose were also determined. The depolymerization of cellulose fibres isolated from LBW was observed to follow both second-order and pseudo-second order kinetics under specific conditions. As such, cello-oligomers of controllable chain lengths could be obtained by adjusting the duration of depolymerization process under optimized conditions.
Carbon dots (CDs) that showed strong blue fluorescence were successfully synthesised from sodium alginate via furnace pyrolysis. The single step pyrolytic synthesis was simple to perform while ...yielded CDs with high photostability, good water solubility and minimum by-products. In order to design the probe with “turn-on” sensing capability, the CDs were screened against a series of metal cations to first “turn-off” the fluorescence. It was found that ferric ions (Fe3+) were most responsive and effective in quenching the fluorescence of CDs. Based on this observation, the conditioning of the probe was performed to ensure the fluorescence was completely quenched, while not overloading the system with Fe3+. At the optimised condition, the CDs-Fe3+ mixture served as a highly specific detection probe for ascorbic acid (AA). The analytical potential of the probe was evaluated and showed a good linear range of response for AA concentration of 24–40μg/mL. The selectivity study against other possible co-existing species was carried out and proved that our unique “turn-on” fluorescence signalling strategy was highly effective and selective towards AA as the target analyte. The probe was demonstrated for quantification of AA in real samples, which was the commercially available vitamin C supplement. The result showed good accuracy with minimum deviation from standard method adopted for validation purpose.
•CDs were successfully synthesised from alginic acid via facile pyrolytic carbonisation.•Blue fluorescence of CDs were quenched by ferric aions and turned on by ascrobic acid.•A unique fluorescence ‘turn-on’ basee on CDs for ascorbic acid sensing has been established.•Ascorbic acid sensing was investigated and anlysed on real semples.
A facile approach for the preparation of hydrophilic starch‐based spherical nanoparticles from native sago (Metroxylon sagu) starch using the drop‐wise solvent exchange method was reported. ...Starch‐maleate monoester (SM) was initially synthesized from native sago starch and maleic anhydride in an aqueous medium, and SM nanoparticles was subsequently precipitated in absolute ethanol under controlled conditions. The present study was focused mainly on modulating of the solvent and non‐solvent systems to prepare SM nanoparticles of different morphologies. The pH of the solvent system and the nature of surfactants being added into the solvent system could influence the morphology of regenerated SM nanoparticles. SM nanoparticles of discrete and spherical shape were regenerated from a basic SM sample solution, or an acidic sample solution in the presence of an appropriate surfactant. SM nanoparticles with mean diameter of about 250 nm was obtained by precipitation in absolute ethanol in the presence of Brij 35 as the surfactant.
In this study, we aim to fabricate a silver nanoparticles (Ag NPs) based electrochemical biosensor for Japanese Encephalitis virus antigen detection. Ag NPs were deposited onto screen-printed carbon ...electrode (SPCE) and the electrochemical properties of the Ag NPs modified SPCE were investigated via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). It was observed that the deposition of Ag NPs onto electrode surface has significantly enhanced the conductivity up to 20.5% than that of bare SPCE. The EIS data indicated limit of detection (LOD) of 2.60 ng/mL (at S/N = 3) towards JEV antigen, with an analysis assay time of 20 min. This presented Ag NPs modified SPCE has demonstrated a promising and rapid alternative to conventional biosensing techniques towards JEV antigen.
Fe3O4/SiO2/TiO2 core-shell nanoparticles were synthesized via a sol-gel method with the aid of sonication. Fe3O4 nanoparticles were being encapsulated within discrete silica nanospheres, and a layer ...of TiO2 shell was then coated directly onto each silica nanosphere. As-synthesized Fe3O4/SiO2/TiO2 core-shell nanoparticles showed enhanced photocatalytic properties as evidenced by the enhanced photodegradation of methylene blue under UV light irradiation.
Particle sizes of nanoparticles have significant effects on thin film properties such as the morphological and optical properties. However, controlling the size and morphology is a challenging task. ...One of the approaches towards overcoming these challenges is by using surfactants. This study reported the effects of several types of biopolymer surfactants on the size of zinc sulphide (ZnS) nanoparticles and the morphology of ZnS nanocrystalline thin films. The ZnS nanocrystalline thin films were fabricated by the spin-coating of ZnS nanoparticles on APTES (3-aminopropyl) triethoxysilane functionalised silica glass. Alginic acid, chitosan and starch were used as the surfactants to control the morphological and optical properties of the thin films. The XRD analysis confirmed the cubic structure and crystalline nature of the ZnS thin films. The field emission scanning electron microscope (FESEM) analysis revealed that the mean particle size of the ZnS nanocrystalline thin film to be with in the range of20-30 nm. The optical measurements revealed that all ZnS thin films exhibited a high transmittance of 92%-99% in the visible range. Photoluminescence (PL) spectra for all thin films were determined and exhibited their respective peaks at 470 nm and 620 nm.
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