scholarly journals Polyelectrolyte coating on superparamagnetic iron oxide nanoparticles as interface between magnetic core and biorelevant media

2016 ◽  
Vol 6 (6) ◽  
pp. 20160068 ◽  
Author(s):  
Etelka Tombácz ◽  
Katalin Farkas ◽  
Imre Földesi ◽  
Márta Szekeres ◽  
Erzsébet Illés ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Colloidal Stability ◽  
High Surface ◽  
Fatal Outcome ◽  
Superparamagnetic Iron Oxide ◽  
Surface Reactivity ◽  
Superparamagnetic Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Biorelevant Media

Nanoparticles do not exist in thermodynamical equilibrium because of high surface free energy, thus they have only kinetic stability. Spontaneous changes can be delayed by designed surface coating. In biomedical applications, superparamagnetic iron oxide nanoparticles (SPIONs) require an optimized coating in order to fulfil the expectation of medicine regulatory agencies and ultimately that of biocompatibility. In this work, we show the high surface reactivity of naked SPIONs due to ≡Fe–OH sites, which can react with H + /OH − to form pH- and ionic strength-dependent charges. We explain the post-coating of naked SPIONs with organic polyacids via multi-site complex bonds formed spontaneously. The excess polyacids can be removed from the medium. The free COOH groups in coating are prone to react with active biomolecules like proteins. Charging and pH- and salt-dependent behaviour of carboxylated SPIONs were characterized quantitatively. The interrelation between the coating quality and colloidal stability measured under biorelevant conditions is discussed. Our coagulation kinetics results allow us to predict colloidal stability both on storage and in use; however, a simpler method would be required to test SPION preparations. Haemocompatibility tests (smears) support our qualification for good and bad SPION manufacturing; the latter ‘promises’ fatal outcome in vivo .

TARGETING CYCLIN B1 WITH ANTISENSE OLIGONUCLETOTIDES- COATED SUPERPARAMAGNETIC IRON OXIDE NANOPARTICLES

2018 ◽  
Vol 6 (10) ◽  
Author(s):  
Hosam Zaghloul ◽  
Doaa A. Shahin ◽  
Ibrahim El- Dosoky ◽  
Mahmoud E. El-awady ◽  
Fardous F. El-Senduny ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Cellular Uptake ◽  
Superparamagnetic Iron Oxide ◽  
Cyclin B1 ◽  
Superparamagnetic Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Mcf7 Cells ◽  
M Phase ◽  
The Impact

Antisense oligonucleotides (ASO) represent an attractive trend as specific targeting molecules but sustain poor cellular uptake meanwhile superparamagnetic iron oxide nanoparticles (SPIONs) offer stability of ASO and improved cellular uptake. In the present work we aimed to functionalize SPIONs with ASO targeting the mRNA of Cyclin B1 which represents a potential cancer target and to explore its anticancer activity. For that purpose, four different SPIONs-ASO conjugates, S-M (1–4), were designated depending on the sequence of ASO and constructed by crosslinking carboxylated SPIONs to amino labeled ASO. The impact of S-M (1–4) on the level of Cyclin B1, cell cycle, ROS and viability of the cells were assessed by flowcytometry. The results showed that S-M3 and S-M4 reduced the level of Cyclin B1 by 35 and 36%, respectively. As a consequence to downregulation of Cyclin B1, MCF7 cells were shown to be arrested at G2/M phase (60.7%). S-M (1–4) led to the induction of ROS formation in comparison to the untreated control cells. Furthermore, S-M (1–4) resulted in an increase in dead cells compared to the untreated cells and SPIONs-treated cells. In conclusion, targeting Cyclin B1 with ASO-coated SPIONs may represent a specific biocompatible anticancer strategy.

Evaluation of Surface-modified Superparamagnetic Iron Oxide Nanoparticles to Optimize Bacterial Immobilization for Bio-separation with the Least Inhibitory Effect on Microorganism Activity

2020 ◽  
Vol 10 (2) ◽  
pp. 166-174
Author(s):  
Mehdi Khoshneviszadeh ◽  
Sarah Zargarnezhad ◽  
Younes Ghasemi ◽  
Ahmad Gholami
Keyword(s):  
Iron Oxide ◽  
Amino Acid ◽  
Magnetic Nanoparticles ◽  
Iron Oxide Nanoparticles ◽  
Surface Coating ◽  
Superparamagnetic Iron Oxide ◽  
Superparamagnetic Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Surface Charges ◽  
Surface Modified

Background: Magnetic cell immobilization has been introduced as a novel, facile and highly efficient approach for cell separation. A stable attachment between bacterial cell wall with superparamagnetic iron oxide nanoparticles (SPIONs) would enable the microorganisms to be affected by an outer magnetic field. At high concentrations, SPIONs produce reactive oxygen species in cytoplasm, which induce apoptosis or necrosis in microorganisms. Choosing a proper surface coating could cover the defects and increase the efficiency. Methods: In this study, asparagine, APTES, lipo-amino acid and PEG surface modified SPIONs was synthesized by co-precipitation method and characterized by FTIR, TEM, VSM, XRD, DLS techniques. Then, their protective effects against four Gram-positive and Gram-negative bacterial strains including Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were examined through microdilution broth and compared to naked SPION. Results: The evaluation of characterization results showed that functionalization of magnetic nanoparticles could change their MS value, size and surface charges. Also, the microbial analysis revealed that lipo-amino acid coated magnetic nanoparticles has the least adverse effect on microbial strain among tested SPIONs. Conclusion: This study showed lipo-amino acid could be considered as the most protective and even promotive surface coating, which is explained by its optimizing effect on cell penetration and negligible reductive effects on magnetic properties of SPIONs. lipo-amino acid coated magnetic nanoparticles could be used in microbial biotechnology and industrial microbiology.

scholarly journals Phosphotungstic acid impregnated niobium coated superparamagnetic iron oxide nanoparticles as recyclable catalyst for selective isomerization of terpenes

RSC Advances ◽  
2021 ◽  
Vol 11 (23) ◽  
pp. 14203-14212
Author(s):  
Luccas Lossano Name ◽  
Sergio Hiroshi Toma ◽  
Helton Pereira Nogueira ◽  
Luis Humberto Avanzi ◽  
Rafael dos Santos Pereira ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Iron Oxide Nanoparticles ◽  
Conversion Efficiency ◽  
Phosphotungstic Acid ◽  
Superparamagnetic Iron Oxide ◽  
Recyclable Catalyst ◽  
Superparamagnetic Iron Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Magnetically Recyclable Catalyst

Conversion efficiency as high as 80–100% and 50% selectivity for camphene and limonene was achieved with low production of polymeric byproducts (18–28%), using a new magnetically recyclable catalyst – SPION-Nb30@HPW.

Sign in / Sign up

Export Citation Format

Share Document