FT-IR images of (a) MNP@DOPA-tertiary amine, (b) MNP@DOPA-mPEG, and (c) MNP@DOPA-sulfonic acid. FT-IR spectra of (a) positively charged Fe3O4 NPs, (b) neutral Fe3O4 NPs and (c) negatively charged Fe3O4 NPs.
Surface engineered nanomaterials and dissertation overview
- Introduction
- Previous researches on surface engineered nanomaterials
- Chemistry of catechol based coating: Research Background
- References
Amphiphilically encapsulated quantum dots with phospholipids and glycoclusters were known as the first approaches of surface-designed nanoparticles (Figure 3).3-5 Amphiphilic molecules are a kind of surfactants and have the characteristics of micelle formation. Nanoparticle ligand exchange strategies are direct covalent attachment of ligands to the nanoparticle surface with bifunctional hydrophilic ligands.9 Ligands consist of a metal coordinating anchor group and a functional group at the same time.
Molecularly smooth and conformal nanocoating by amine-mediated redox
Introduction
A remarkable enhancement of the affinity to metal oxide surfaces of the compound was identified by density functional theory (DFT) calculations.
Experimental section
The raw NEXAFS spectra were normalized to the jet stream using a grid located upstream of the jet line. Finally, a vacuum height of 20 Å along the z axis was introduced to avoid self-interaction of the surface sheet model.
Result and discussion
The hydrodynamic sizes of OEGC-coated IONPs were several hundreds of nanometers due to incomplete coating of the OEGC (Figure 2.8d). These newly developed peaks suggested a change in the substitution pattern of the aromatic part of OEGC. Wide applications were also considered due to the high stability and biocompatibility of the PEG group.
The stability of TBC-AEE forms decreased in the order of AEEs attached to C6, C5, and C3 (see step 4 in Figure 2.15a). This result suggests that the catechol-amine adduct provides stable binding with ferrous ions through the electron-donating effects of the amine substituent on the ferrous ions. The first role of AA is to increase the basicity of the solution, which facilitates the coordination of catechol to the metal oxide surface.
Conclusion
F.; Alessandra, P.; Alessandro, P., Colloidal stability of iron oxide nanocrystals coated with a PEG-based tetra-catechol wetting agent. H.; Hyeon, T., Large-scale synthesis of uniform and ultrasmall iron oxide nanoparticles for high-resolution T1 magnetic resonance imaging contrast agents. Ren, F.; Zhao, C.; Sun, G.; Liang, R.; Li, Z., Mussel-inspired adhesive and sticky hydrogel based on nanoclay-confined dopamine polymerization.
Polito, L.; Colombo, M.; Monti, D.; Melato, S.; Caneva, E.; Prosperi, D., Solving the Structure of Ligands Bound to the Surface of Superparamagnetic Iron Oxide Nanoparticles by High-Resolution Magic-Angle Spinning NMR Spectroscopy. A.; Vander Elst, L., HR-MAS NMR spectroscopy: an innovative tool for characterizing iron oxide nanoparticle tracers for molecular imaging. Amine-supported catechol-based nanocoating on iron oxide nanoparticles for high-resolution magnetic resonance angiography.
Amine-assisted catechol-based nanocoating on iron oxide nanoparticles for high-
- Introduction
- Experimental section
- Result and discussion
- Conclusion
- References
Dynamic light scattering (DLS) measurements show that IONP@MCP/AEE has a monomodal and narrow size distribution in D.W. The morphology of the IONPs is preserved and no evidence of etching is observed. IONP@MCP/AEE is stable over a wide pH range (5–11) and at NaCl concentrations up to 2 M for at least one month (Figure 3.5a). FT-IR studies were performed on IONP@Oleic acid, MCP, IONP@MCP and IONP@MCP/AEE to investigate the molecular structure of the surface.
The signal was dramatically reduced for IONP@MCP compared to MCP and IONP@MCP/AEE. In addition, the MR enhancement signal was maintained for 80 min, indicating that IONP@MCP/AEE is useful for achieving steady-state imaging. TEM image of (a) 3-nm-sized IONPs capped with oleic acid and (b) 3-nm-sized IONPs coated with AEE-assisted MCP. a) HD of IONP@MCP/AEE at different pH and salt concentrations over time.
Facile synthesis and direct characterization of surface-charge-controlled magnetic
Introduction
Facile synthesis and direct characterization of magnetic iron oxide nanoparticles with controlled surface charge and their role in gene. Imaging based on FT-IR spectroscopy can be used to confirm analytical data obtained by ToF-SIMS imaging25, 26 as well as to provide further molecular structural and bonding information. Here, we present the facile synthesis and accurate surface characterization of well-designed and charge-controlled (positive, neutral, and negative) iron oxide (Fe3O4) NPs based on the use of dopamine-containing block copolymer-bearing ligands; thorough analysis of ligand molecules; and interactions of the resulting NPs with living cells.
ToF-SIMS imaging analysis together with FT-IR spectroscopy imaging enabled the molecular identification and spatial distribution for both the NPs and the surface conjugated (and unconjugated) ligands, providing direct evidence for the presence and integrity of the ligands on the NPs . Furthermore, we demonstrated that an appropriate surface charge modification plays a key role in intracellular uptake as well as in efficient gene transfection into suspension-type cell, the Jurkat human leukemic T cell, which is generally considered very difficult.28 Our study of surface - charge-controlled NPs for biomedical applications such as efficient gene transfection are summarized in Figure 4.1. Our strategy for a deep understanding of interactions between NPs and mammalian cells depends on the NP surface charge, brought about by well-designed surface chemistry; and chemical information-based surface image analysis, and the NPs gene transfection efficiency.42 Reproduced in part with permission from H.Na, H.H.Kim, and J.G.Son et al., Applied Surface Science Copyright 2019 ELSEVIER.
Experimental section
The obtained molecular weight (Mw) of the tertiary amine ligand was 8860 (PDI=1.09). The morphology and size analysis of the iron oxide NPs were examined by transmission electron microscopy (TEM, JEOL, JEM-2100) operated at 200 kV. . After a 24-h incubation period with the NPs, the cells were treated with 20 μl of MTT stock solution (5 mg/ml). The cells were incubated for 3 h and DMSO (200 μl) was added to each well to dissolve the insoluble formazan salt.
The cells were incubated for 3 h and optical densities were then measured at 450 nm using a microplate reader, SynergyH1 (Biotek, U.K.). The cells were seeded in a 6-well cell culture plate at a density of 5 x 10 5 cells per well. well, 24 h before transfection. After incubation for 24 h, cells were treated with 50 nM siRNA targeting NOTCH1 complexed with positively charged Fe3O4 NP or Lipofectamine 2000TM (Invitrogen, Carlsbad, CA).
Result and discussion
For ligands with different surface charges, the polymer synthesis was designed using two monomers, one as the common anchor (dopamine) and the other as the distinguishable functional group (tertiary amine for positive, PEG for neutral and sulfonic acid for negative surface). 42 Partially reproduced with permission from H.Na, H.H.Kim and J.G.Son et al., Applied Surface Science Copyright 2019 ELSEVIER. a) TEM images of Fe3O4 NPs before and after ligand exchange with DOPA-tertiary amine (positive), DOPA-mPEG (neutral) and DOPA-sulfonic acid (negative). Iron-related ions of Fe3O4 NPs ([Fe]+ and [FeO2]) are indicated by blue diamonds, and fragment ions of polymer ligands for tertiary amine, PEG, and sulfonic acid are indicated by orange diamonds.42 Reproduced in part with permission from H.Na , H.H. Kim and J.G. Son et al., Applied surface science Copyright 2019 ELSEVIER. The FT-IR peak assignments for the free ligands and ligand-coated Fe3O4 NPs are shown in Figure 4.9g.
Using this analytical approach, we were able to characterize the surface of Fe3O4 NPs after ligand replacement. However, positively charged Fe3O4 NPs (i.e., MNP@DOPA-tertiary amine) caused a slight decrease in cell viability at high concentrations (150 and 300 µg/mL). Biological interactions of suspension-type Jurkat cells with positively charged Fe3O4 NPs. a) Bio-TEM images of Jurkat cells after treatment with MNP@DOPA-tertiary amine at a concentration of 10 µg/mL.
Conclusion
Petri-Fink, Assessment of the in vitro and in vivo toxicity of superparamagnetic iron oxide nanoparticles, Chem. Rotello, Efficient gene delivery vectors by tuning the surface charge density of amino acid-functionalized gold nanoparticles, ACS Nano. Liang, Enhanced Gene Delivery and siRNA Silencing by Gold Nanoparticles Coated with Charge-Reversal Polyelectrolyte, ACS Nano.
Alessandro, Colloidal stability of iron oxide nanocrystals coated with a PEG-based tetra-catechol wetting agent, Nanotechnology. Nanoparticle surface charge affects distribution, uptake and lymph node trafficking by pulmonary antigen-presenting cells, Nanomedicine: Nanotechnology, Biology and Medicine. Seed-mediated synthesis of ultra-long copper nanowires and their application as transparent conducting electrodes.
Introduction
Experimental section
Result and discussion
It was essential to control the injected amount of CuCl2 to monitor variations in the average diameter of the resulting Cu NWs. As the Cl−/Cu2+ ratio in the injection solution increased, the apparent diameter of the Cu NWs decreased (Figure 5.5). To investigate the growth pathway, the external appearance of the reaction solution was monitored (Figure 5.6).
After injection of the CuCl2 solution, the color of the solution changed dramatically from purple-black to pale brown within minutes (Figures 5.6a and 5.6b). It can be seen from Figure 5.7b that the average size of NPs decreased from 14.3 nm to about 3 nm. The percolation threshold became significantly lower due to the high aspect ratio of Cu NWs.
Conclusion
나는 무명의 울산에서 길고 짧은 20대를 보내면서 많은 분들의 도움과 응원으로 이 논문을 쓸 수 있었다. 먼저, 항상 따뜻한 관심과 사랑으로 저를 아낌없이 가르쳐주시고 가르쳐주신 박종남 선생님께 진심으로 감사의 말씀을 전하고 싶습니다. 연구실에서 만난 선후배, 동기들에게도 감사드립니다.
앞으로도 좋은 일만 가득하시길 진심으로 바랍니다. 그리고 실험실에서 처음 만났고 실험에 대해 알게 해준 창진, 기철, 대철, 청호에게도 감사 인사를 전하고 싶습니다. 마지막으로 언제나 큰 힘이 되어주시는 부모님께 진심으로 감사드립니다.
