Preparation of core–shell Fe<sub>3</sub>O<sub>4</sub>@poly(dopamine) magnetic nanoparticles for biosensor construction

Martín, Miriam; Salazar, Pedro; Villalonga, Reynaldo; Campuzano, Susana; Pingarrón, José M.; González–Mora, José Luis

doi:10.1039/c3tb21171a

Cited by 221 publications

(146 citation statements)

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“…In its high-T (austenite) phase, Ni-Mn-Ga has a cubic L2 1 Heusler structure. At the M-phase transition temperature T M , the lattice undergoes a transformation, which can be described by a periodic shuffling of (011) planes along the ½011 direction [6]. Depending on the stoichiometry and the residual stress, the resulting low-T M phase is commonly found to have either tetragonal or orthorhombic symmetry, with a modulation period of ten (10M) or 14 (14M) atomic layers [6,7], respectively.…”

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“…At the M-phase transition temperature T M , the lattice undergoes a transformation, which can be described by a periodic shuffling of (011) planes along the ½011 direction [6]. Depending on the stoichiometry and the residual stress, the resulting low-T M phase is commonly found to have either tetragonal or orthorhombic symmetry, with a modulation period of ten (10M) or 14 (14M) atomic layers [6,7], respectively. For specific stoichiometries, e.g., Ni 2þx Mn 1−x Ga with x ≲ 0.1, a premartensitic phase (PM phase) is observed above T M [3] with the transition temperature T PM up to 50 K above T M [3,8].…”

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confidence: 99%

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Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy

et al. 2015

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The origin of the martensitic transition in the magnetic shape memory alloy Ni-Mn-Ga has been widely discussed. While several studies suggest it is electronically driven, the adaptive martensite model reproduced the peculiar nonharmonic lattice modulation. We used femtosecond spectroscopy to probe the temperature and doping dependence of collective modes, and scanning tunneling microscopy revealed the corresponding static modulations. We show that the martensitic phase can be described by a complex charge-density wave tuned by magnetic ordering and strong electron-lattice coupling. DOI: 10.1103/PhysRevLett.115.076402 PACS numbers: 71.45.Lr, 78.47.-p, 81.30.Kf, 81.70.Fy Magnetic shape memory alloys present a new type of multifunctional materials, which display strong coupling between the magnetic and structural degrees of freedom. The ferromagnetic Ni-Mn-Ga alloy serves as a prototype system, displaying a giant 12% magnetic-field-induced strain in its low-temperature (T) martensitic phase (M phase) [1,2]. Since in Ni-Mn-Ga the M-phase transition can be tuned far above the room temperature by changing stoichiometry or doping [3,4], this alloy is of special technological interest [1,2,5].The rich phase diagram of Ni 2þxþy Mn 1−x Ga 1−y is characterized by a complex sequence of phase transitions. In its high-T (austenite) phase, Ni-Mn-Ga has a cubic L2 1 Heusler structure. At the M-phase transition temperature T M , the lattice undergoes a transformation, which can be described by a periodic shuffling of (011) planes along the ½011 direction [6]. Depending on the stoichiometry and the residual stress, the resulting low-T M phase is commonly found to have either tetragonal or orthorhombic symmetry, with a modulation period of ten (10M) or 14 (14M) atomic layers [6,7], respectively. For specific stoichiometries, e.g., Ni 2þx Mn 1−x Ga with x ≲ 0.1, a premartensitic phase (PM phase) is observed above T M [3] with the transition temperature T PM up to 50 K above T M [3,8]. In the PM phase, the lattice displays a harmonic threefold modulation with the wave vector q PM ¼ q max ð 1 3 ; 1 3 ; 0Þ. Inelastic neutron scattering studies of the high-T cubic phase [9] showed a dramatic softening of the TA-2 phonon branch at q PM , indicative of a Kohn anomaly. These observations [9][10][11][12], together with the observed opening of a pseudogap at T PM [8,13], suggest an electronic instability within the Peierls scenario to be driving the PM-phase transition. The observation of a phase mode in the 10M phase [14] also suggested the electronic instability. In fact, the electronic band structure studies [11,15,16] revealed the possible Fermi surface nesting conditions for all of the observed structural modulations. However, for the case of the 14M martensite, it was argued that the modulated phase can be constructed from nonmodulated martensitic unit cells [17,18]. This adaptive martensite scenario [17][18][19] recently received considerable attention.To determine which theory gives a more appropriate physical picture of the pha...

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Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy

et al. 2015

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“…11,12 AuNPs have attracted the interest of scientists especially in the areas of 13 biosensing, 14 imaging, 15 and drug delivery. 2 Magnetic nanoparticles (MNPs) have generated considerable interest in the scientific world especially in the area of biomedicine and technology, particularly in magnetic storage media, 16 biosensing, 17,18 inks and paints, 19 drug delivery and contrast agents in magnetic resonance imaging. 20 NPs are generally synthesized in either aqueous or organic solutions and thus require sophisticated coating for stability.…”

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Nanoparticle-cored dendrimers: functional hybrid nanocomposites as a new platform for drug delivery systems

2015

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“…layers. [5][6][7] The layer can be further modified with hydrophilic and/or biocompatible functional groups, including C=C, -NH-, -Br and sulfonyl, then dipole interaction of core is shielded, and agglomeration of particles is prevented. 3,[8][9][10] Core-shell MMIP can provide specific recognition because of the mesoporous and microporous molecular scale cavities, and can shorten the processing time of sample due to the excellent settling performance and ease to be separated from the matrix through an external magnetic field.…”

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confidence: 99%

Preparation and Performance of an Estradiol Templated Magnetic Sphere of Molecularly Imprinted Cryogel

Wang¹,

Tian²,

Yan³

et al. 2017

J. Braz. Chem. Soc.

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An estradiol templated core-shell magnetic molecularly imprinted cryogel (MMIC) was synthesized to selectively extract and analyze estradiol in milk powder. The microsphere of Fe 3 O 4 @SiO 2 was firstly prepared on Fe 3 O 4 with ethyl silicate and 3-methyl propyl trimethoxy silane. Then the polymerization of α-methacrylic acid and ethylene glycol dimethyl acrylate was carried out on Fe 3 O 4 @SiO 2 at −20 °C for 24 h with estradiol as template. The morphology and microstructure of MMIC were investigated by transmission electron microscopy and infrared spectrogram. When used as chromatographic stationary phase, MMIC showed good selectivity and chromatographic performance for the template. Spiked milk powder samples were used to examine the adsorption capacity and selectivity of MMIC, giving recoveries of 92-101% and limit of detection 0.8-1.2 ng g −1 .Experimental results indicate good reproducibility with relative standard deviation from 2.2 to 4.5% (n = 3) at spiked levels of estradiol 10, 50, and 100 ng g -1 .Keywords: magnetic sphere, molecularly imprinted cryogel, estradiol, milk powder IntroductionSample preparation is of vital importance in an analysis for reducing the interference of impurities, concentrating the low abundant components, and improving the sensitivity and selectivity. Sample pretreatment occupies more than 60% of the entire time, while it presents poor reproducibility and accuracy. Thus, a sound sample pretreatment is crucial to guarantee the accuracy, reliability of the results, as well as the efficiency of analytical determination. Solid phase extraction (SPE) has widely been used in the extraction, purification, and enrichment of analytes in environmental, food, and biological samples. However, SPE cannot eliminate the interference of matrix in complex samples because the conventional adsorbents, such as normal, reverse, and ionic phase and other special adsorbents, have poor selectivity. Molecularly imprinted polymer (MIP) is a kind of inclusive compound prepared from template, monomer, and cross linker. There is a covalent bond or hydrogen bond or Van der Waals' force between template and polymer.2 When template molecule is removed, a specific cavity with binding sites complementary to the size, shape, and functional group of template is formed in the polymer.2 Molecularly imprinted polymers based solid phase extraction (MIP-SPE) can be implemented in selective separation, analysis, and preparation of high-purity target substance. MIP-SPE can achieve rapid and high efficiency of extraction of the analytes, because of high specific surface area and high mass transfer rate. 3,4Core-shell magnetic molecularly imprinted polymer (MMIP) is a new type of functional composite, the magnetic core (such as Fe 3 O 4 ) of which is covered with inorganic (SiO 2 , Al 2 O 3 , etc.) or organic (surfactant, polymer, etc.) layers. [5][6][7] The layer can be further modified with hydrophilic and/or biocompatible functional groups, including C=C, -NH-, -Br and sulfonyl, then dipole interaction of core is...

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Preparation of core–shell Fe₃O₄@poly(dopamine) magnetic nanoparticles for biosensor construction

Cited by 221 publications

References 48 publications

Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy

Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy

Nanoparticle-cored dendrimers: functional hybrid nanocomposites as a new platform for drug delivery systems

Preparation and Performance of an Estradiol Templated Magnetic Sphere of Molecularly Imprinted Cryogel

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Preparation of core–shell Fe3O4@poly(dopamine) magnetic nanoparticles for biosensor construction

Cited by 221 publications

References 48 publications

Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy

Collective Modes and Structural Modulation in Ni-Mn-Ga(Co) Martensite Thin Films Probed by Femtosecond Spectroscopy and Scanning Tunneling Microscopy

Nanoparticle-cored dendrimers: functional hybrid nanocomposites as a new platform for drug delivery systems

Preparation and Performance of an Estradiol Templated Magnetic Sphere of Molecularly Imprinted Cryogel

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Preparation of core–shell Fe₃O₄@poly(dopamine) magnetic nanoparticles for biosensor construction