scholarly journals Magnetically reusable and well-dispersed nanoparticles for oxygen detection in water

2021 ◽  
Author(s):  
Huahua Cui ◽  
Shanshan Wu ◽  
Lei Wang ◽  
Xiangzhong Sun ◽  
He Zhang ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
High Stability ◽  
Magnetic Nanoparticle ◽  
Oxygen Sensing ◽  
Oxygen Sensors ◽  
Biological Applications ◽  
E Coli ◽  
One Step ◽  
Continued Use ◽  
Strong Linear Relationship

Abstract In this study, we aimed to synthesize magnetically well-dispersed nanosensors for detecting dissolved oxygen (DO) in water, and explore their biological applications. Firstly, we synthesized two kinds of magnetic nanoparticle with average sizes of approximately 82 nm by one-step emulsion polymerization: polystyrene magnetic nanoparticles (Fe3O4@Os1-PS) and polymethylmethacrylate magnetic nanoparticles (Fe3O4@Os1-PMMA). Both types of nanoparticle present good dispersibility and fluorescence stability. The nanoparticles could be used as oxygen sensors that exhibited a high DO-sensitivity response in the range 0-39.30 mg/L, with a strong linear relationship. The nanoparticles have good magnetic properties, and so they could be recycled by magnet for further use. Recovered Fe3O4@Os1-PS still presented high stability after continued use in oxygen sensing for one month. Furthermore, Fe3O4@Os1-PS was employed for detecting the bacterial oxygen consumption of Escherichia coli (E-coli) to monitor the metabolism of bacteria. The results show that Fe3O4@Os1-PS provide high biocompatibility and non-toxicity. Polystyrene magnetic nanoparticles therefore present significant potential for application in biological oxygen sensing.

Magnetic Nanoparticle-Antibody Conjugates for the Separation of Escherichia coli O157:H7 in Ground Beef

2005 ◽  
Vol 68 (9) ◽  
pp. 1804-1811 ◽  
Author(s):  
MADHUKAR VARSHNEY ◽  
LIJU YANG ◽  
XIAO-LI SU ◽  
YANBIN LI
Keyword(s):  
Escherichia Coli ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Ground Beef ◽  
Immunomagnetic Separation ◽  
Capture Efficiency ◽  
Escherichia Coli O157 ◽  
Mechanical Mixing ◽  
E Coli ◽  
Antibody Conjugates

The immunomagnetic separation with magnetic nanoparticle-antibody conjugates (MNCs) was investigated and evaluated for the detection of Escherichia coli O157:H7 in ground beef samples. MNCs were prepared by immobilizing biotin-labeled polyclonal goat anti–E. coli antibodies onto streptavidin-coated magnetic nanoparticles. For bacterial separation, MNCs were mixed with inoculated ground beef samples, then nanoparticle-antibody–E. coli O157:H7 complexes were separated from food matrix with a magnet, washed, and surface plated for microbial enumeration. The capture efficiency was determined by plating cells bound to nanoparticles and unbound cells in the supernatant onto sorbitol MacConkey agar. Key parameters, including the amount of nanoparticles and immunoreaction time, were optimized with different concentrations of E. coli O157:H7 in phosphate-buffered saline. MNCs presented a minimum capture efficiency of 94% for E. coli O157:H7 ranging from 1.6 × 101 to 7.2 × 107 CFU/ml with an immunoreaction time of 15 min without any enrichment. Capture of E. coli O157:H7 by MNCs did not interfere with other bacteria, including Salmonella enteritidis, Citrobacter freundii, and Listeria monocytogenes. The capture efficiency values of MNCs increased from 69 to 94.5% as E. coli O157:H7 decreased from 3.4 × 107 to 8.0 × 100 CFU/ml in the ground beef samples prepared with minimal steps (without filtration and centrifugation). An enrichment of 6 h was done for 8.0 × 100 and 8.0 × 101 CFU/ml of E. coli O157:H7 in ground beef to increase the number of cells in the sample to a detectable level. The results also indicated that capture efficiencies of MNCs for E. coli O157:H7 with and without mechanical mixing during immunoreaction were not significantly different (P > 0.05). Compared with microbeads based immunomagnetic separation, the magnetic nanoparticles showed their advantages in terms of higher capture efficiency, no need for mechanical mixing, and minimal sample preparation.

scholarly journals Preparation of magnetic nanoparticles by one step synthesis with morphology of particles changed based on time of reaction and temperature treatment

2020 ◽  
Vol 16 (1) ◽  
pp. 1-10
Author(s):  
Tomáš Solný ◽  
Petr Ptáček ◽  
Tomáš Opravil ◽  
Lucie Dlabajová ◽  
Matěj Březina ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Temperature Treatment ◽  
One Step ◽  
Time Of Reaction

scholarly journals Understanding intracellular nanoparticle trafficking fates through spatiotemporally resolved magnetic nanoparticle recovery

2021 ◽  
Author(s):  
Emily Sheridan ◽  
Silvia Vercellino ◽  
Lorenzo Cursi ◽  
Laurent Adumeau ◽  
James A. Behan ◽  
...  
Keyword(s):  
Decision Making ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Magnetic Extraction

We describe how magnetic nanoparticles can be used to study intracellular nanoparticle trafficking, and how magnetic extraction may be integrated with downstream analyses to investigate nanoscale decision-making events.

scholarly journals Therapeutic Potential of Magnetic Nanoparticle-Based Human Adipose-Derived Stem Cells in a Mouse Model of Parkinson’s Disease

2021 ◽  
Vol 22 (2) ◽  
pp. 654
Author(s):  
Ka Young Kim ◽  
Keun-A Chang
Keyword(s):  
Parkinson’S Disease ◽  
Stem Cells ◽  
Parkinson's Disease ◽  
Magnetic Nanoparticles ◽  
Substantia Nigra ◽  
Mouse Model ◽  
Magnetic Nanoparticle ◽  
Imaging System ◽  
Therapeutic Potential ◽  
Adipose Derived Stem Cells

Parkinson’s disease (PD) is a progressive neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra. Several treatments for PD have focused on the management of physical symptoms using dopaminergic agents. However, these treatments induce various adverse effects, including hallucinations and cognitive impairment, owing to non-targeted brain delivery, while alleviating motor symptoms. Furthermore, these therapies are not considered ultimate cures owing to limited brain self-repair and regeneration abilities. In the present study, we aimed to investigate the therapeutic potential of human adipose-derived stem cells (hASCs) using magnetic nanoparticles in a 6-hydroxydopamine (6-OHDA)-induced PD mouse model. We used the Maestro imaging system and magnetic resonance imaging (MRI) for in vivo tracking after transplantation of magnetic nanoparticle-loaded hASCs to the PD mouse model. The Maestro imaging system revealed strong hASCs signals in the brains of PD model mice. In particular, MRI revealed hASCs distribution in the substantia nigra of hASCs-injected PD mice. Behavioral evaluations, including apomorphine-induced rotation and rotarod performance, were significantly recovered in hASCs-injected 6-OHDA induced PD mice when compared with saline-treated counterparts. Herein, we investigated whether hASCs transplantation using magnetic nanoparticles recovered motor functions through targeted brain distribution in a 6-OHDA induced PD mice. These results indicate that magnetic nanoparticle-based hASCs transplantation could be a potential therapeutic strategy in PD.

scholarly journals Complete biosynthesis of a sulfated chondroitin in Escherichia coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Scale Up ◽  
Production Methods ◽  
E Coli ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Microbial Product ◽  
Dry Cell Weight ◽  
One Step ◽  
Dry Cell

AbstractSulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production–chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 μg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.

Simulated Clustering Dynamics of Colloidal Magnetic Nanoparticles

Nanoscale ◽  
2021 ◽  
Author(s):  
Frederik Laust Durhuus ◽  
Lau Halkier Wandall ◽  
Mathias Hoeg Boisen ◽  
Mathias Kure ◽  
Marco Beleggia ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Self Assembly ◽  
Biomedical Applications ◽  
Magnetic Nanoparticle ◽  
Bottom Up ◽  
Novel Materials ◽  
Nanoparticle Clusters ◽  
Clustering Dynamics

Magnetically guided self-assembly of nanoparticles is a promising bottom-up method to fabricate novel materials and superstructures, such as, for example, magnetic nanoparticle clusters for biomedical applications. The existence of assembled...

scholarly journals Transient cell stiffening triggered by magnetic nanoparticle exposure

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Jose E. Perez ◽  
Florian Fage ◽  
David Pereira ◽  
Ali Abou-Hassan ◽  
Sophie Asnacios ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Early Time ◽  
Population Level ◽  
Short Time Scale ◽  
Initial Contact ◽  
Almost All ◽  
The Impact ◽  
Stiffening Effect

Abstract Background The interactions between nanoparticles and the biological environment have long been studied, with toxicological assays being the most common experimental route. In parallel, recent growing evidence has brought into light the important role that cell mechanics play in numerous cell biological processes. However, despite the prevalence of nanotechnology applications in biology, and in particular the increased use of magnetic nanoparticles for cell therapy and imaging, the impact of nanoparticles on the cells’ mechanical properties remains poorly understood. Results Here, we used a parallel plate rheometer to measure the impact of magnetic nanoparticles on the viscoelastic modulus G*(f) of individual cells. We show how the active uptake of nanoparticles translates into cell stiffening in a short time scale (< 30 min), at the single cell level. The cell stiffening effect is however less marked at the cell population level, when the cells are pre-labeled under a longer incubation time (2 h) with nanoparticles. 24 h later, the stiffening effect is no more present. Imaging of the nanoparticle uptake reveals almost immediate (within minutes) nanoparticle aggregation at the cell membrane, triggering early endocytosis, whereas nanoparticles are almost all confined in late or lysosomal endosomes after 2 h of uptake. Remarkably, this correlates well with the imaging of the actin cytoskeleton, with actin bundling being highly prevalent at early time points into the exposure to the nanoparticles, an effect that renormalizes after longer periods. Conclusions Overall, this work evidences that magnetic nanoparticle internalization, coupled to cytoskeleton remodeling, contributes to a change in the cell mechanical properties within minutes of their initial contact, leading to an increase in cell rigidity. This effect appears to be transient, reduced after hours and disappearing 24 h after the internalization has taken place.

One-Step Preparation of Competent E. coli: Transformation and Storage of Bacterial Cells in the Same Solution

2021 ◽  
Vol 2021 (11) ◽  
pp. pdb.prot101212 ◽  
Author(s):  
Michael R. Green ◽  
Joseph Sambrook
Keyword(s):  
Escherichia Coli ◽  
Convenient Method ◽  
Plasmid Dna ◽  
Transformation Efficiency ◽  
Bacterial Cells ◽  
E Coli ◽  
One Step ◽  
And Storage

This protocol describes a convenient method for the preparation, use, and storage of competent Escherichia coli. The reported transformation efficiency of this method is ∼5 × 107 transformants/µg of plasmid DNA.

Succinate Functionalization of Hyperbranched Polyglycerol-Coated Magnetic Nanoparticles as a Draw Solute During Forward Osmosis

2015 ◽  
Vol 15 (10) ◽  
pp. 8279-8284 ◽  
Author(s):  
Hee-Man Yang ◽  
Hye Min Choi ◽  
Sung-Chan Jang ◽  
Myeong Jin Han ◽  
Bum-Kyoung Seo ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Succinic Anhydride ◽  
Water Flux ◽  
Forward Osmosis ◽  
Feed Solution ◽  
Carboxyl Groups ◽  
Solute Leakage ◽  
One Step ◽  
Hyperbranched Polyglycerol ◽  
The One

Hyperbranched polyglycerol-coated magnetic nanoparticles (SHPG-MNPs) were functionalized with succinate groups to form a draw solute for use in a forward osmosis (FO). After the one-step synthesis of hyperbranched polyglycerol-coated magnetic nanoparticles (HPG-MNPs), the polyglycerol groups on the surfaces of the HPG-MNPs were functionalized with succinic anhydride moieties. The resulting SHPG-MNPs showed no change of size and magnetic property compared with HPGMNPs and displayed excellent dispersibility in water up to the concentration of 400 g/L. SHPG-MNPs solution showed higher osmotic pressure than that of HPG-MNPs solution due to the presence of surface carboxyl groups in SHPG-MNPs and could draw water from a feed solution across an FO membrane without any reverse draw solute leakage during FO process. Moreover, the water flux remained nearly constant over several SHPG-MNP darw solute regeneration cycles applied to the ultrafiltration (UF) process. The SHPG-MNPs demonstrate strong potential for use as a draw solute in FO processes.

One-step synthesis of a graphene-carbon nanotube hybrid decorated by magnetic nanoparticles

Carbon ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 2764-2771 ◽  
Author(s):  
Xiao Zhu ◽  
Guoqing Ning ◽  
Zhuangjun Fan ◽  
Jinsen Gao ◽  
Chunming Xu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Magnetic Nanoparticles ◽  
One Step
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