Magnetic Nanoparticle–Polyelectrolyte Interaction: A Layered Approach for Biomedical Applications

2008 ◽  
Vol 8 (8) ◽  
pp. 4033-4040 ◽  
Author(s):  
John E. Wong ◽  
Akhilesh K. Gaharwar ◽  
Detlef Müller-Schulte ◽  
Dhirendra Bahadur ◽  
Walter Richtering
Keyword(s):  
Magnetic Nanoparticles ◽  
Magnetic Nanoparticle ◽  
Layer By Layer ◽  
Layer Deposition ◽  
Dimethylammonium Chloride ◽  
Modified Magnetic Nanoparticles ◽  
Post Modification ◽  
Nanoparticle Core ◽  
Modification Of The Surface

This study describes the surface modification of magnetic nanoparticles using two different approaches. The first approach consists of an in situ modification of the surface during the precipitation of the magnetic nanoparticles while the second approach consists of a post-modification of the surface after the formation of the magnetic nanoparticles. In the latter case, we adopted the Layer-by-Layer assembly of polyelectrolyte multilayers of poly(diallyl-dimethylammonium) chloride and poly(styrenesulfonate) to build a polymeric shell around the magnetic nanoparticle core, thereby intentionally conferring to this hybrid core–shell the same charge as the charge of the polyelectrolyte deposited in the last layer. Electrophoretic measurements reveal charge reversal indicating successful Layer-by-Layer deposition while magnetization studies show that the superparamagnetic behavior is not much affected by the presence of polyelectrolytes on the modified magnetic nanoparticles. Fourier transform infrared and thermogravimetry analysis results underline that the various polyelectrolytes employed, in both the methodologies adopted, were successfully bound to the nanoparticles.

scholarly journals A platform for light-controlled formation of free-stranding lipid membranes

2020 ◽  
Vol 17 (163) ◽  
pp. 20190740 ◽  
Author(s):  
Nikolay V. Ryzhkov ◽  
Ekaterina V. Skorb
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membranes ◽  
Science And Technology Studies ◽  
Separation Distance ◽  
Layer By Layer ◽  
Net Charge ◽  
Novel Approach ◽  
Layer Deposition ◽  
Transmembrane Channels

The engineering of artificial cells is one of the most significant scientific challenges. Thus, controlled fabrication and in situ monitoring of biomimetic nanoscale objects are among the central issues in current science and technology. Studies of transmembrane channels and cell mechanics often require the formation of lipid bilayers (LBs), their modification and their transfer to a particular place. We present here a novel approach for remotely controlled manipulation of LBs. Layer-by-layer deposition of polyethyleneimine and poly(sodium 4-styrenesulfonate) on a nanostructured TiO 2 photoanode was performed to obtain a surface with the desired net charge and to enhance photocatalytic performance. The LB was deposited on top of a multi-layer positive polymer cushion by the dispersion of negative vesicles. The separation distance between the electrostatically linked polyelectrolyte cushion and the LB can be adjusted by changing the environmental pH, as zwitter-ionic lipid molecules undergo pH-triggered charge-shifting. Protons were generated remotely by photoanodic water decomposition on the TiO 2 surface under 365 nm illumination. The resulting pH gradient was characterized by scanning vibrating electrode and scanning ion-selective electrode techniques. The light-induced reversible detachment of the LB from the polymer-cushioned photoactive substrate was found to correlate with suggested impedance models.

In Situ Spectroscopic Approach to Atomic Layer Deposition

2002 ◽  
Vol 745 ◽  
Author(s):  
Martin M. Frank ◽  
Yves J. Chabal ◽  
Glen D. Wilk
Keyword(s):  
Infrared Spectroscopy ◽  
Atomic Layer Deposition ◽  
Aluminum Oxide ◽  
Atomic Layer ◽  
Gate Oxide ◽  
Silicon Surfaces ◽  
Oxide Growth ◽  
Layer By Layer ◽  
Layer Deposition

ABSTRACTThere is great need for a mechanistic understanding of growth chemistry during atomic layer deposition (ALD) of films for electronic applications. Since commercial ALD reactors are presently not equipped for in situ spectroscopy, we have constructed a model reactor that enables single-pass transmission infrared spectroscopy to be performed in situ on a layer-by-layer basis. We demonstrate the viability of this approach for the study of aluminum oxide growth on silicon surfaces, motivated by alternative gate oxide applications. Thanks to submonolayer dielectric and adsorbate sensitivity, we can quantify oxide thicknesses and hydroxyl areal densities on thermal and chemical SiO2/Si(100) substrates. Methyl formation and hydroxyl consumption upon initial trimethylaluminum (TMA) reaction can also be followed. We verify that in situ grown Al2O3 films are compatible in structure to films grown in a commercial ALD reactor.

Separating and characterizing functional nitrogen degraders via magnetic-nanoparticle mediated isolation technology in high concentration of ammonia nitrogen wastewater treatment

2020 ◽  
Author(s):  
Meng Yin ◽  
Yujiao Sun ◽  
Danyang Zheng ◽  
Lei Wang ◽  
Xiaohui Zhao ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Magnetic Nanoparticles ◽  
Activated Sludge ◽  
Microbial Community Structure ◽  
Magnetic Nanoparticle ◽  
Ammonia Nitrogen ◽  
Stable Conditions

<p>Magnetic-nanoparticle mediated isolation (MMI) is a new method for isolating active functional microbes from complex microorganisms without substrate labeling. In this study, the composition and properties of the magnetic nanoparticles （MNPs）were characterized by a number of techniques. And then the MNPs were added to activated sludge rich in ammonia nitrogen-degrading bacteria after long-term stable treatment,  another set of experiments plus urea was set as the only carbon source in the system. Compared with the group without MNPs, degradation experiment results showed that the ammonia nitrogen degradation ability of a group of MNPs was slightly improved. The high-throughput sequencing results showed that the addition of MNPs did not change the microbial community structure of activated sludge under long-term stable conditions, and that the addition of urea as a nitrogen source significantly changed the microbial community structure. RDA analysis results also showed that Comamonadaceae_unclassified and Thiobacillus absolutely dominated in situ ammonia degradation, and the change in dominant genera showed the same trend as the degradation rate of ammonia nitrogen. It has also proved that the complex flora after adding magnetic nanoparticles is more adaptable to newly introduced pollutants, using MMI to study pollutant-degrading microorganisms under in-situ conditions has a broad application prospect.</p>

Thermo-responsive adsorption and separation of amino acid enantiomers using smart polymer-brush-modified magnetic nanoparticles

2016 ◽  
Vol 40 (4) ◽  
pp. 3194-3207 ◽  
Author(s):  
Ya-Ya Song ◽  
Xiao-Dong Song ◽  
Heng Yuan ◽  
Chang-Jing Cheng
Keyword(s):  
Amino Acid ◽  
Magnetic Nanoparticles ◽  
Chiral Recognition ◽  
Magnetic Nanoparticle ◽  
Polymer Brush ◽  
Smart Polymer ◽  
Amino Acid Enantiomers ◽  
Modified Magnetic Nanoparticles ◽  
Recognition Capability

A novel type of multifunctional magnetic nanoparticle with highly chiral recognition capability, excellent thermo-sensitive adsorption and decomplexation properties toward amino acid enantiomers, and recyclability was developed in this study.

scholarly journals Development of an in-line magnetometer for flow chemistry and its demonstration for magnetic nanoparticle synthesis

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Maximilian O. Besenhard ◽  
Dai Jiang ◽  
Quentin A. Pankhurst ◽  
Paul Southern ◽  
Spyridon Damilos ◽  
...  
Keyword(s):  
Quality Control ◽  
Magnetic Nanoparticles ◽  
High Throughput ◽  
High Throughput Screening ◽  
Magnetic Nanoparticle ◽  
Nanoparticle Synthesis ◽  
Flow Chemistry ◽  
Continuous Quality ◽  
Highly Sensitive

A highly sensitive magnetometer for flow chemistry to characterise magnetic nanoparticles in solution, in situ and in real-time is presented. This facilitates continuous quality control and high-throughput screening of magnetic nanoparticle syntheses.

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