Separation of nanoparticles in a density gradient: FeCo@C and gold nanocrystals.
Ontology highlight
ABSTRACT:
SUBMITTER: Sun X
PROVIDER: S-EPMC2656675 | biostudies-literature | 2009
REPOSITORIES: biostudies-literature
Publications
Separation of nanoparticles in a density gradient: FeCo@C and gold nanocrystals.
Sun Xiaoming X Tabakman Scott M SM Seo Won-Seok WS Zhang Li L Zhang Guangyu G Sherlock Sarah S Bai Lu L Dai Hongjie H
Angewandte Chemie (International ed. in English) 20090101 5
Similar Datasets
Project description:This article describes the stabilization and postsynthetic separation of gold nanostars (AuNS) synthesized with a morpholine-based Good's buffer, 3-(N-morpholino)propanesulfonic acid. Resuspension of AuNS in ultrapure water improved the shape stability of the particles over 30 days. We demonstrated the sorting of nanostars via rate-zonal centrifugation through a linear sucrose gradient based on branch length and number. We determined that one round of centrifugation was sufficient for separation. Also, we improved the structural homogeneity and stability of the nanoparticles through the optimization of the storage conditions and established a robust method to sort AuNS based on size and shape.
| S-EPMC6641882 | biostudies-literature
Project description:FeCo/graphitic carbon shell (FeCo/GC) nanocrystals (?4-5 nm in diameter) with ultrahigh magnetization are synthesized, functionalized, and developed into multifunctional biocompatible materials. We demonstrate the ability of this material to serve as an integrated system for combined drug delivery, near-infrared (NIR) photothermal therapy, and magnetic resonance imaging (MRI) in vitro. We show highly efficient loading of doxorubicin (DOX) by ?-stacking on the graphitic shell to afford FeCo/GC-DOX complexes and pH sensitive DOX release from the particles. We observe enhanced intracellular drug delivery by FeCo/GC-DOX under 20 min of NIR laser (808 nm) induced hyperthermia to 43 °C, resulting in a significant increase of FeCo/GC-DOX toxicity toward breast cancer cells. The synergistic cancer cell killing by FeCo/GC-DOX drug delivery under photothermal heating is due to a ?two-fold enhancement of cancer cell uptake of FeCo/GC-DOX complex and the increased DOX toxicity under the 43 °C hyperthermic condition. The combination of synergistic NIR photothermally enhanced drug delivery and MRI with the FeCo/GC nanocrystals could lead to a powerful multimodal system for biomedical detection and therapy.
| S-EPMC3043169 | biostudies-literature
Project description:ObjectivesChemotherapeutic drugs induce senescence in cancer cells but, unlike replicative senescence or oncogene-induced senescence, do so rather inefficiently and depending on DNA damage. A thorough understanding of the biology of chemotherapy-induced senescent cells requires their isolation from a mixed population of adjacent senescent and non-senescent cancer cells.Materials and methodsWe have developed and optimized a rapid iodixanol (OptiPrep)-based gradient centrifugation system to identify, isolate and characterize doxorubicin (DXR)-induced senescent hepatocellular carcinoma (HCC) cells (HepG2 and Huh-7) in vitro.ResultsAfter cellular exposure to DXR, we used iodixanol gradient-based centrifugation to isolate and re-plate cells on collagen-coated flasks, despite their low or null proliferative capacity. The isolated cell populations were enriched for DXR-induced senescent HCC cells, as confirmed by proliferation arrest assay, and β-galactosidase and DNA damage-dependent γH2A.X staining.ConclusionsAnalysing pure cultures of chemotherapy-induced senescent versus non-responsive cancer cells will increase our knowledge on chemotherapeutic mechanisms of action, and help refine current therapeutic strategies.
| S-EPMC6869531 | biostudies-literature
Project description:Sustainable production and use of carbon nanotube (CNT)-enabled materials require efficient assessment of CNT environmental hazards, including the potential for CNT bioaccumulation and biomagnification in environmental receptors. Microbes, as abundant organisms responsible for nutrient cycling in soil and water, are important ecological receptors for studying the effects of CNTs. Quantification of CNT association with microbial cells requires efficient separation of CNT-associated cells from individually dispersed CNTs and CNT agglomerates. Here, we designed, optimized, and demonstrated procedures for separating bacteria (Pseudomonas aeruginosa) from unbound multiwall carbon nanotubes (MWCNTs) and MWCNT agglomerates using sucrose density gradient centrifugation. We demonstrate separation of protozoa (Tetrahymena thermophila) from MWCNTs, bacterial agglomerates, and protozoan fecal pellets by centrifugation in an iodixanol solution. The presence of MWCNTs in the density gradients after centrifugation was determined by quantification of 14C-labeled MWCNTs; the recovery of microbes from the density gradient media was confirmed by optical microscopy. Protozoan intracellular contents of MWCNTs and of bacteria were also unaffected by the designed separation process. The optimized methods contribute to improved efficiency and accuracy in quantifying MWCNT association with bacteria and MWCNT accumulation in protozoan cells, thus supporting improved assessment of CNT bioaccumulation.
| S-EPMC5132190 | biostudies-literature
Project description: Not available
| S-EPMC3361505 | biostudies-literature
Project description:1. Sputum samples from a total of 18 asthmatic and chronic bronchitic patients were examined by analytical density-gradient ultracentrifugation. CsBr was used as the dispersal agent and dense electrolyte. 2. The patterns show two main groups of components, banding at about 1.3g/ml and 1.5g/ml; in addition, a few samples showed a further zone at approx. 1.65g/ml. These components were identified as protein, secretory glycoprotein and DNA respectively. The glycoprotein zone was frequently hypersharp, and usually contained two or more partially resolved bands; it was always well resolved from the protein. 3. The glycoprotein components were isolated from nine representative sputum samples by density-gradient ultracentrifugation on a preparative scale. Analytical density-gradient ultracentrifugation was used to monitor the efficiency of the separations. 4. Some sputum samples separated cleanly under these conditions, the glycoprotein being essentially devoid of free protein; in others, separation was apparently incomplete, although computer simulation indicated that the conditions were adequate to ensure separation. Further density-gradient separations in CsCl were necessary with several samples before satisfactory products were obtained; mixtures of CsCl with guanidinium chloride were no more effective than CsCl alone. The reluctance to separate indicates a very strong, but non-covalent, interaction between protein and glycoprotein, probably associated with the gelatinous character of the secretion. 5. The purified glycoprotein components were characterized analytically and physicochemically. They contained N-acetylgalactosamine, N-acetylglucosamine, galactose, fucose and N-acetylneuraminic acid, and had an amino acid composition in which serine, threonine and proline predominated; however, aspartic acid, glutamic acid and cystine were also appreciable. The glycoproteins were of very high molecular weight, and usually showed more than one component in sedimentation velocity; their distribution in a density gradient indicated a substantial, but largely monotonic, density heterogeneity. 6. Thiol reduction decreased the molecular weight very substantially, but the products were relatively more homogeneous than the native materials. The amino acid composition was changed significantly and a small and variable proportion of protein or peptide was liberated. It is concluded that the native materials are disulphide-linked aggregates, probably through a cross-linking peptide, in confirmation of earlier studies.
| S-EPMC1183702 | biostudies-other
Project description:Developing photoactivatable theranostic platforms with integrated functionalities of biocompatibility, targeting, imaging contrast, and therapy is a promising approach for cancer diagnosis and therapy. Here, we report a theranostic agent based on a hybrid nanoparticle comprising fullerene nanocrystals and gold nanoparticles (FGNPs) for photoacoustic imaging and photothermal therapy. Compared to gold nanoparticles and fullerene crystals, FGNPs exhibited stronger photoacoustic signals and photothermal heating characteristics by irradiating light with an optimal wavelength. Our studies demonstrated that FGNPs could kill cancer cells due to their photothermal heating characteristics in vitro. Moreover, FGNPs that are accumulated in tumor tissue via the enhanced permeation and retention effect can visualize tumor tissue due to their photoacoustic signal in tumor xenograft model mice. The theranostic agent with FGNPs shows promise for cancer therapy.
| S-EPMC9105889 | biostudies-literature
Project description:Electromagnetized gold nanopartilces can facilitate hippocampal neurogenesis.
2021-02-19 | GSE167006 | GEO
Project description:A full understanding and mediation of nanoparticle-serum protein interactions is key to design nanoparticles with vivid functions within the body, and to solve this problem one needs to differentiate and characterize individual nano-protein conjugates. In this paper, the authors applied capillary electrophoresis combined with inductively coupled plasma mass spectrometry detection to study the behavior of gold nanoparticles of different geometry, size and surface functionalization upon interacting with serum proteins and their mixtures. Due to high-resolution and -sensitivity benefits of this combined technique baseline separations were attained for free nanoparticles (at real-life doses) and different protein conjugates, and the conversion into the protein-bound form was scrutinized in terms of reaction time.
| S-EPMC5681605 | biostudies-literature
Project description:We used Au nanoparticles (Au-NPs) as a model for studying particle specific effects of manufactured nanomaterials (MNMs) by examining the toxicogenomic responses in a model soil organism, free living nematode Caenorhabditis elegans. Global genome expression for nematodes exposed to 4-nm citrate-coated Au-NPs at the LC10 (5.9 mg L-1) revealed significant differential expression of 797 genes. The levels of expression for five genes (apl-1, dyn-1, act-5, abu-11, and hsp-4) were confirmed independently with qRT-PCR. Seven common biological pathways associated with 38 of these genes were identified. Activation of 26 pqn/abu genes from noncanonical Unfolded Protein Response (UPR) pathway and up-regulation of molecular chaperones (hsp-16.1, hsp-70, hsp-3 and hsp-4) were observed and are likely indicative of endoplasmic reticulum stress. Inhibition of abu-11 with RNAi showed increase in mortality in Au-NP exposed nematodes suggesting possible involvement of abu-11 (a gene associated with specific to C. elegans UPR) in a protective mechanism against Au-NPs. Exposure to Au-NPs also caused activation of genes involved in apoptosis and necrosis and resulted ultimately in 10% mortality. These results demonstrate that Au-NPs are bioavailable and cause adverse effects to a model ecoreceptor which activate both general and specific biological pathways.
2012-04-16 | GSE32521 | GEO