Magnetic Nanotubes for Magnetic-Field-Assisted Bioseparation, Biointeraction, and Drug Delivery

Abstract

Tubular structure of nanoparticles is highly attractive due to their structural attributes, such as the distinctive inner and outer surfaces, over conventional spherical nanoparticles. Inner voids can be used for capturing, concentrating, and releasing species ranging in size from large proteins to small molecules. Distinctive outer surfaces can be differentially functionalized with environment-friendly and/or probe molecules to a specific target. Magnetic particles have been extensively studied in the field of biomedical and biotechnological applications, including drug delivery, biosensors, chemical and biochemical separation and concentration of trace amounts of specific targets, and contrast enhancement in magnetic resonance imaging (MRI). Therefore, by combining the attractive tubular structure with magnetic property, the magnetic nanotube (MNT) can be an ideal candidate for the multifunctional nanomaterial toward biomedical applications, such as targeting drug delivery with MRI capability. Here, we successfully synthesized magnetic silica-iron oxide composite nanotubes and demonstrated the magnetic-field-assisted chemical and biochemical separations, immunobinding, and drug delivery.

Nanosized Cation-Deficient Fe−Ti Spinel: A Novel Magnetic Sorbent for Elemental Mercury Capture from Flue Gas

“…As shown in Figure 5h, a new peak at 713.3 eV appeared in the spectral region of Fe 2p, which may be attributed to Fe 2 (SO 4 ) 3 . Once Fe 3þ cations on (Fe 2 Ti) 0.8 O 4 transformed to Fe 2 (SO 4 ) 3 , the involved cation vacancies would be destroyed and cannot be regenerated.…”

“…The S 2p peaks (shown in Figure 5k) mainly centered at 168.4 and 170.1 eV, which may be assigned to SO 4 2-and HSO 4 -, respectively. Meanwhile, a subtle peak centered at 166.9 eV can be observed, which was ascribed to SO 3 2-. Furthermore, a new peak at 532.3 eV (shown in Figure 5j) appeared in the spectral region of O 1s, which may be assigned to SO 4 2-.…”

Microwave enhanced silica encapsulation of magnetic nanoparticles

“…MN@SiO 2 (400 mL TEOS) demonstrate magnetic response (Fig. 5b) to external fields, which implies usefulness for various bioapplications including magnetically assisted cell separation, 36 drug delivery 37 and removal of micro-organisms. 38 The size of our products is …”

Nanopartículas magnéticas: o cobalto

“…O principal aspecto envolvido foi o de selecionar a cadeia alquila do ligante. Tipicamente, a reação de decomposição de 3 4 [Co(ç -C H )(ç -C H ] foi conduzida a uma pressão 8 C H ] propiciou a formação de nanopartículas 8 12 polidispersas com diâmetro médio de 10 nm. Verificou-se, também, que o tamanho da cadeia alquila do grupo amina afeta o tamanho e morfologia das nanopartículas obtidas [25].…”

“…Além disso, os materiais nanoestruturados são magnéticos, o que significa que os mesmos seguem as leis de Coulomb e podem, portanto, serem manipulados por um campo magnético externo [6][7]. Também, as nanopartículas magnéticas podem responder a uma variação magnéti-ca em função do tempo, o que conduz a um efeito de transferência de energia do campo magnético excitante para as nanopartículas [8]. Assim, as nanoestruturas podem sofrer aquecimento, o que propicia o seu uso como agentes epitérmicos ou como agentes quimioterápicos e radioterápicos, conduzindo a uma destruição das células malignas [9].…”