Preparation and characterization of carboxyl-group functionalized superparamagnetic nanoparticles and t he potential for bio-applications

Abstract

Neste trabalho, foi desenvolvido um método para preparação de nanopartículas magnéticas monodispersas funcionalizadas com grupos carboxila. Maguemita de dimensões nanométricas (y-Fe 2 O 3 , 7,0 ± 1,0 nm) foi sintetizada usando-se o método de coprecipitação térmica e subseqüentemente coberta com grupos funcionais por copolimerização em suspensão conduzida em uma etapa. Estudos de espectroscopia de infravermelho com transformada de Fourier e análise termogravimétrica confirmaram o sucesso da funcionalização dos grupos carboxila na superfície dos nanocristais magnéticos. Esta superfície química torna possível a purificação de DNA baseada em SPRI (imobilização reversível em fase sólida). Assim, as nanopartículas foram empregadas para isolamento de DNA de cultura de células bacterianas e os resultados demonstraram sua aplicabilidade na preparação de DNA. In this work, a method was developed to prepare monodispersed carboxyl-group functionalized magnetic nanoparticles. Nanosized maghemite (y-Fe 2 O 3 , 7.0 ± 1.0 nm) was synthesized using thermal co-precipitation method and subsequently coated with functional groups by one-step suspension copolymerization. The Fourier transform infrared spectroscopy study and thermogravitmetric analyses confirmed the successful functionalization of carboxyl groups on the surface of magnetic nanocrystals. The surface chemistry makes it possible for SPRI (solid phase reversible immobilization)-based DNA purification. Thus the nanoparticles were employed to isolate plasmid DNA from bacterial cell culture and the results demonstrated its applicability in DNA preparation.

Effect of Surface Charge and Hydrophobicity Modulation on the Antibacterial and Antibiofilm Potential of Magnetic Iron Nanoparticles

“…The unfunctionalized MNPs showed Fe-O characteristic absorption band at 634.4 and 557.5 cm −1 [48]. Two other bands around 3422.7 cm −1 and 1634.9 cm −1 correspond to stretching and bending vibrations of surface hydroxyl groups on surface of MNPs [49]. OAMNPs showed OA coating characteristic bands at 2923.8 and 2852.9 cm −1 which correspond to CH 3 stretching.…”

Synthesis, characterization, and antimicrobial activity of an ampicillin-conjugated magnetic nanoantibiotic for medical applications

“…The initial mass loss for the MNPs at temperatures up to 200°C may be related to the removal of surface hydroxyl groups and/or adsorbed water. [48][49][50] At temperatures higher than 200°C, the mass loss was 1.9% for the MNPs and 4.5% for the CS-MNPs, which may be attributed to amorphous iron hydroxide decomposition followed by iron oxide formation for the former and evaporation followed by decomposition of the CS-MNPs for the latter. By comparing the weight loss curves for the MNPs and CS-MNPs, the quantity of CS coated on the MNPs was estimated at 2.6%.…”

In vitro removal of toxic heavy metals by poly(γ-glutamic acid)-coated superparamagnetic nanoparticles

“…However, the Ms value reported for bulk magnetite is relatively higher (89-92 emu/g), 28 which may be attributed to the small-particle surface effect resulting from the large surface area to volume ratio of synthesized SPIONs. 28,29 A drop in Ms value by 12.5% upon the coating of SPIONs with PGA confirmed the PGA coating on SPIONs. Nevertheless, an abundant magnetic property was still retained for PGASPIONs to provide fast separation using a magnet.…”