► A simple and easy nanoprecipitation method was successfully used to synthesize starch nanoparticles with controllable sizes. ► The shape and size of the starch nanoparticles can be controlled by ...the synthesis parameters. ► Starch nanoparticles with mean particles size of 150nm were obtained in the presence of surfactants during precipitation.
Starch nanoparticles of particle size range between 300nm and 400nm were synthesized by a simple nanoprecipitation method from native sago starch (Metroxylon sagu). Starch nanoparticles were formed by controlled precipitation through drop-wise addition of dissolved native starch solution to excess absolute ethanol. The size and shape of starch nanoparticles were modulated varying the synthesis parameters including the use of appropriate surfactant. Starch nanoparticles with mean diameter of about 150nm were obtained in the presence of surfactants during precipitation. Both solvent and non-solvent systems used in the synthesis method were aqueous-based and the method was facile, and easy to perform as compared to other synthesis approaches previously reported.
Controllable particles sizes of starch nanoparticles were synthesized via a precipitation in water-in-oil microemulsion approach. Microemulsion method offers the advantages of ultralow interfacial ...tension, large interfacial area, and being thermodynamically stable and affords monodispersed nanoparticles. The synthesis parameters such as stirring rates, ratios of oil/cosurfactant, oil phases, cosurfactants, and ratios of water/oil were found to affect the mean particle size of starch nanoparticles. Starch nanoparticles with mean particles sizes of 109 nm were synthesized by direct nanoprecipitation method, whereas by using precipitation in microemulsion approach, starch nanoparticles with smaller mean particles sizes of 83 nm were obtained.
A series of bimetallic copper-nickel (CuNix, x = 0.1, 0.2, 0.5 and 1) nanoparticles supported on activated carbon (AC) were prepared by deposition-precipitation method for the oxidation of benzyl ...alcohol to benzaldehyde using hydrogen peroxide as oxidising agent. Analyses by means of X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) confirmed that Cu and Ni was successfully added on the surface of activated carbon. CuNi1/AC showed the best catalytic activity for the oxidation of benzyl alcohols to the corresponding aldehyde within a short reaction period at 80 °C. The catalytic performance is significantly enhanced by the addition of equal amount of Ni as compared to the monometallic counterpart. This result indicates the synergistic effect between Ni and Cu particles in the catalytic oxidation reaction.
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•Bimetallic CuNix/AC nanoparticles catalysts with different Cu-Ni ratios are prepared.•CuNix/AC catalysts are efficient for catalysing benzyl alcohol to benzaldehyde under mild conditions.•The addition of Ni at optimum amount for CuNix/AC catalysts improves the catalytic activity.•The presence of higher amounts of Ni resulted in more active sites to account for the superior catalytic performance.
Cellulose films with antimicrobial property were prepared by incorporation of chitosan nanoparticles as antimicrobial agents into the cellulose films. The antimicrobial property of these chitosan ...nanoparticles-doped cellulose films against Escherichia coli (E. coli) was evaluated via diffusion assay method, minimum inhibitory concentration (MIC) method, and minimum bactericidal concentration (MBC) method. The effects of antimicrobial agent amount, size-related property (nanoparticles and bulk chitosan), and crosslinking by citric acid on antimicrobial activity of cellulose films were studied. It was observed that the antimicrobial activity was enhanced when chitosan nanoparticles were used as compared to when bulk chitosan was used. A maximum E. coli inhibition of 85% was achieved with only 5% (v/v) doping of chitosan nanoparticles into the cellulose films. Crosslinking of the cellulose films with citric acid was observed to have resulted in 50% reduction of water absorbency and a slight increase of E. coli inhibition by 3% for chitosan nanoparticles-doped cellulose films.
Curcumin was loaded onto starch nanoparticles by using in situ nanoprecipitation method and water-in-oil microemulsion system. Curcumin loaded starch nanoparticles exhibited enhanced solubility in ...aqueous solution as compared to free curcumin. Effects of formulation parameters such as types of reaction medium, types of surfactant, surfactant concentrations, oil/ethanol ratios, loading time, and initial curcumin concentration were found to affect the particle size and loading efficiency (LF) of the curcumin loaded starch nanoparticles. Under optimum conditions, curcumin loaded starch nanoparticles with mean particles size of 87 nm and maximum loading efficiency of 78% were achieved. Curcumin was observed to release out from starch nanoparticles in a sustained way under physiological pH over a period of 10 days.
This paper aims to synthesize starch acetate nanoparticles for controlled release of piperine. Starch acetate is synthesized by chemically modified sago starch with acetylation reaction. Starch ...acetate nanoparticles with mean particle sizes of 110 nm are obtained by controlled precipitation through drop‐wise addition of dissolved starch acetate solution into excess absolute ethanol. Piperine is loaded onto starch acetate nanoparticles and native starch nanoparticles via the in situ nanoprecipitation process. Starch acetate nanoparticles exhibit higher piperine loading capacity as compared to native starch nanoparticles with the maximum loading capacity of 0.46 and 0.33 mg mg–1, respectively. Piperine is observed to release from starch acetate nanoparticles in a slow and sustained manner at pH 1.2 for 24 h. In contrast, piperine is observed to fully release from native starch nanoparticles after 16 h.
Starch acetate nanoparticles are prepared and studied. These starch acetate nanoparticles are used as nanocarriers for the controlled release of piperine.
•Cellulose depolymerization using an ionic liquid as solvent and a solid catalyst.•Cellulose depolymerizes via a second order reaction under optimized conditions.•Optimized depolymerization enables ...precise control of cello-oligomer chain lengths.
Cellulose extracted from printed paper wastes were selectively depolymerized under controlled conditions into cello-oligomers of controllable chain lengths via dissolution in an ionic liquid, 1-allyl-3-methylimidazolium chloride (AMIMCl), and in the presence of an acid catalyst, Amberlyst 15DRY. The depolymerization process was optimized against reaction temperature, concentration of acid catalyst, and reaction time. Despite rapid initial depolymerization process, the rate of cellulose depolymerization slowed down gradually upon prolonged reaction time, with 75.0wt% yield of regenerated cello-oligomers (mean Viscosimetric Degree of Polymerization value of 81) obtained after 40min. The depolymerization of cellulose fibers at 80°C appeared to proceed via a second-order kinetic reaction with respect to the catalyst concentration of 0.23mmol H3O+. As such, the cellulose depolymerization process could afford some degree of control on the degree of polymerization or chain lengths of cello-oligomers formed.
Highly porous cellulose beads of controllable sizes were successfully prepared from regenerated cellulose of printed paper wastes based on a facile dissolution and controlled precipitation approach. ...Pure and dispersed cellulose fibers were isolated from finely ground paper wastes by undergoing initial pretreatment and maceration processes in sodium hydroxide solution (NaOH, 12wt%). Dispersed cellulose fibers were subsequently dissolved in an ionic liquid (1-allyl-3-methylimidozoium chloride, AMIMCl) to form a homogenous cellulose solution. Highly porous cellulose beads of controllable sizes within the range of 0.4–2.2mm in diameter were prepared by precipitation in a coagulation bath of ultrapure water under controlled conditions. Cellulose beads of various mean sizes exhibited substantially different specific surface area which ranged between 107m2/g and 498m2/g. Cellulose beads of biocompatibility, high porosity and specific surface area are therefore potentially useful as drug delivery carriers.
•Highly porous cellulose beads derived from printed paper wastes.•Mean diameters of cellulose beads are modulated via synthesis conditions.•Specific surface area inversely proportional to mean diameter of cellulose beads.
Spherically shaped cellulose nanoparticles with average particle diameter range between 70 and 365 nm were fabricated from cotton fibers by a simple nanoprecipitation method. The average particle ...diameter of cellulose nanoparticles could be precisely controlled by modulating the synthesis conditions such as cellulose solution concentration and volume ratio of solvent/non-solvent. Methylene blue (MB) as a model hydrophilic drug was loaded onto cellulose nanoparticles via the in-situ nanoprecipitation process. The loading efficiency and release profile of MB were observed to be affected by the average particle diameter of cellulose nanoparticles.
(a) SEM image of cellulose fibers facial cotton and (b) TEM micrograph of cellulose nanoparticles prepared from 0.01 w/v % of cellulose solution. Display omitted
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