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Fulltext Effects of selected polysorbate and sucrose ester emulsifiers on the physicochemical properties of astaxanthin nanodispersions

Anarjan N, Tan CP

Molecules, 2013 Jan 09;18(1):768-77.
PMID: 23303336 DOI: 10.3390/molecules18010768

The effects of selected nonionic emulsifiers on the physicochemical characteristics of astaxanthin nanodispersions produced by an emulsification/evaporation technique were studied. The emulsifiers used were polysorbates (Polysorbate 20, Polysorbate 40, Polysorbate 60 and Polysorbate 80) and sucrose esters of fatty acids (sucrose laurate, palmitate, stearate and oleate). The mean particle diameters of the nanodispersions ranged from 70 nm to 150 nm, depending on the emulsifier used. In the prepared nanodispersions, the astaxanthin particle diameter decreased with increasing emulsifier hydrophilicity and decreasing carbon number of the fatty acid in the emulsifier structure. Astaxanthin nanodispersions with the smallest particle diameters were produced with Polysorbate 20 and sucrose laurate among the polysorbates and the sucrose esters, respectively. We also found that the Polysorbate 80- and sucrose oleate-stabilized nanodispersions had the highest astaxanthin losses (i.e., the lowest astaxanthin contents in the final products) among the nanodispersions. This work demonstrated the importance of emulsifier type in determining the physicochemical characteristics of astaxanthin nano-dispersions.

Matched MeSH terms: Nanospheres/chemistry*
An electrochemical DNA biosensor fabricated from graphene decorated with graphitic nanospheres

Raja Jamaluddin RZA, Tan LL, Chong KF, Heng LY

Nanotechnology, 2020 Nov 27;31(48):485501.
PMID: 32748805 DOI: 10.1088/1361-6528/abab2e

Graphene decorated with graphitic nanospheres functionalized with pyrene butyric acid (PBA) is used for the first time to fabricate a DNA biosensor. The electrode was formed by attaching a DNA probe onto PBA, which had been stacked onto a graphene material decorated with graphene nanospheres (GNSs). The nanomaterial was drop-coated onto a carbon screen-printed electrode (SPE) to create the GNS-PBA modified electrode (GNS-PBA/SPE). A simple method was used to produce GNS by annealing graphene oxide (GO) solution at high temperature. Field emission scanning electron micrographs confirmed the presence of a spherical shape of GNS with a diameter range of 40-80 nm. A stable and uniform PBA-modified GNS (GNS-PBA) was obtained with a facile ultrasonication step. Thus allowing aminated DNA probes of genetically modified (GM) soybean to be attached to the nanomaterials to form the DNA biosensor. The GNS-PBA/SPE exhibited excellent electrical conductivity via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) tests using potassium ferricyanide (K3[Fe(CN)6]) as the electroactive probe. By employing an anthraquinone monosulfonic acid (AQMS) redox intercalator as the DNA hybridization indicator, the biosensor response was evaluated using the DPV electrochemical method. A good linear relationship between AQMS oxidation peak current and target DNA concentrations from 1.0 × 10-16 to 1.0 × 10-8 M with a limit of detection (LOD) of less than 1.0 × 10-16 M was obtained. Selectivity experiments revealed that the voltammetric GM DNA biosensor could discriminate complementary sequences of GM soybean from non-complementary sequences and hence good recoveries were obtained for real GM soybean sample analysis. The main advantage of using GNS is an improvement of the DNA biosensor analytical performance.

Matched MeSH terms: Nanospheres/chemistry*
Predicting the fluorescent enhancement rate by gold and silver nanospheres using finite-difference time-domain analysis

Centeno A, Xie F, Alford N

IET Nanobiotechnol, 2013 Jun;7(2):50-8.
PMID: 24046905

Metal-induced fluorescence enhancement (MIFE) is a promising strategy for increasing the sensitivity of fluorophores used in biological sensors. This study uses the finite-difference time-domain technique to predict the fluorescent enhancement rate of a fluorophore molecule in close proximity to a gold or silver spherical nanoparticle. By considering commercially available fluorescent dyes the computed results are compared with the published experimental data. The results show that MIFE is a complex coupling process between the fluorophore molecule and the metal nanoparticle. Nevertheless using computational electromagnetic techniques to perform calculations it is possible to calculate, with reasonable accuracy, the fluorescent enhancement. Using this methodology it will be possible to consider different shaped metal nanoparticles and any supporting substrate material in the future, an important step in building reliable biosensors capable of detecting low levels of proteins tagged with fluorescence molecules.

Matched MeSH terms: Nanospheres/chemistry*
Biocompatible disulphide cross-linked sodium alginate derivative nanoparticles for oral colon-targeted drug delivery

Ayub AD, Chiu HI, Mat Yusuf SNA, Abd Kadir E, Ngalim SH, Lim V

Artif Cells Nanomed Biotechnol, 2019 Dec;47(1):353-369.
PMID: 30691309 DOI: 10.1080/21691401.2018.1557672

The application of layer-by-layer (LbL) approach on nanoparticle surface coating improves the colon-specific drug delivery of insoluble drugs. Here, we aimed to formulate a self-assembled cysteamine-based disulphide cross-linked sodium alginate with LbL self-assembly to improve the delivery of paclitaxel (PCX) to colonic cancer cells. Cysteamine was conjugated to the backbone of oxidized SA to form a core of self-assembled disulphide cross-linked nanospheres. P3DL was selected for PCX loading and fabricated LbL with poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSCMA) resulting from characterization and drug release studies. P3DL-fabricated PCX-loaded nanospheres (P3DL/PAH/PSSCMA) exhibited an encapsulation efficiency of 77.1% with cumulative drug release of 45.1%. Dynamic light scattering analysis was reported at 173.6 ± 2.5 nm with polydispersity index of 0.394 ± 0.105 (zeta potential= -58.5 mV). P3DL/PAH/PSSCMA demonstrated a pH-dependent swelling transition; from pH 1 to 7 (102.2% increase). The size increased by 33.0% in reduction response study after incubating with 10 mM glutathione (day 7). HT-29 cells showed high viabilities (86.7%) after treatment with the fabricated nanospheres at 0.8 µg/mL. Cellular internalization was successful with more than 70.0% nanospheres detected in HT-29 cells. Therefore, this fabricated nanospheres may be considered as potential nanocarriers for colon cancer-targeted chemotherapeutic drug delivery.

Matched MeSH terms: Nanospheres/chemistry
Functionalized Carbon Nano-scale Drug Delivery Systems From Biowaste Sago Bark For Cancer Cell Imaging

Abdul Manaf SA, Hegde G, Mandal UK, Wui TW, Roy P

Curr Drug Deliv, 2017;14(8):1071-1077.
PMID: 27745545 DOI: 10.2174/1567201813666161017130612

BACKGROUND: Nano-scale carbon systems are emerging alternatives in drug delivery and bioimaging applications of which they gradually replace the quantum dots characterized by toxic heavy metal content in the latter application.
OBJECTIVE: The work intended to use carbon nanospheres synthesized from biowaste Sago bark for cancer cell imaging applications.
METHODS: This study synthesised carbon nanospheres from biowaste Sago bark using a catalyst-free pyrolysis technique. The nanospheres were functionalized with fluorescent dye coumarin-6 for cell imaging. Fluorescent nanosytems were characterized by field emission scanning electron microscopy-energy dispersive X ray, photon correlation spectroscopy and fourier transform infrared spectroscopy techniques.
RESULTS: The average size of carbon nanospheres ranged between 30 and 40 nm with zeta potential of -26.8 ± 1.87 mV. The percentage viability of cancer cells on exposure to nanospheres varied from 91- 89 % for N2a cells and 90-85 % for A-375 cells respectively. Speedy uptake of the fluorescent nanospheres in both N2a and A-375 cells was observed within two hours of exposure.
CONCLUSION: Novel fluorescent carbon nanosystem design following waste-to-wealth approach exhibited promising potential in cancer cell imaging applications.

Matched MeSH terms: Nanospheres/chemistry*