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Although tremendous advances have been made in preparing porous crystals from molecular precursors 1,2 , there are no general ways of designing and making topologically diversified porous colloidal crystals over the 10-1,000 nm length scale. Control over porosity in this size range would enable the tailoring of molecular absorption and storage, separation, chemical sensing, catalytic and optical properties of such materials. Here, a universal approach for synthesizing metallic open-channel superlattices with pores of 10 to 1,000 nm from DNA-modified hollow colloidal nanoparticles (NPs) is reported. By tuning hollow NP geometry and DNA design, one can adjust crystal pore geometry (pore size and shape) and channel topology (the way in which pores are interconnected). The assembly of hollow NPs is driven by edge-to-edge rather than face-to-face DNA-DNA interactions. Two new design rules describing this assembly regime emerge from these studies and are then used to synthesize 12 open-channel superlattices with control over crystal symmetry, channel geometry and topology. The open channels can be selectively occupied by guests of the appropriate size and that are modified with complementary DNA (for example, Au NPs)., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Colloidal crystal engineering of complex, low-symmetry architectures is challenging when isotropic building blocks are assembled. Here we describe an approach to generating such structures based upon programmable atom equivalents (nanoparticles functionalized with many DNA strands) and mobile electron equivalents (small particles functionalized with a low number of DNA strands complementary to the programmable atom equivalents). Under appropriate conditions, the spatial distribution of the electron equivalents breaks the symmetry of isotropic programmable atom equivalents, akin to the anisotropic distribution of valence electrons or coordination sites around a metal atom, leading to a set of well-defined coordination geometries and access to three new low-symmetry crystalline phases. All three phases represent the first examples of colloidal crystals, with two of them having elemental analogues (body-centred tetragonal and high-pressure gallium), while the third (triple double-gyroid structure) has no known natural equivalent. This approach enables the creation of complex, low-symmetry colloidal crystals that might find use in various technologies., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Multiplexed surface encoding is achieved by positioning two different sizes of gold nanocubes on gold surfaces with precisely defined locations for each particle via template-confined, DNA-mediated nanoparticle assembly. As a proof-of-concept demonstration, cubes with 86 and 63 nm edge lengths are assembled into arrangements that physically and spectrally encrypt two sets of patterns in the same location. These patterns can be decrypted by mapping the absorption intensity of the substrate at λ = 773 and 687 nm, respectively. This multiplexed encoding platform dramatically increases the sophistication and density of codes that can be written using colloidal nanoparticles, which may enable high-security, high-resolution encoding applications.

Disorders of blood vessels cause a range of severe health problems. As a powerful vasodilator and cellular second messenger, nitric oxide (NO) is known to have beneficial vascular functions. However, NO typically has a short half-life and is not specifically targeted. On the other hand, high-density lipoproteins (HDLs) are targeted natural nanoparticles (NPs) that transport cholesterol in the systemic circulation and whose protective effects in vascular homeostasis overlap with those of NO. Evolving the AuNP-templated HDL-like nanoparticles (HDL NPs), a platform of bioinspired HDL, we set up a targeted biomimetic nanotherapy for vascular disease that combines the functions of NO and HDL. A synthetic S-nitrosylated (SNO) phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphonitrosothioethanol) was synthesized and assembled with S-containing phospholipids and the principal protein of HDL, apolipoprotein A-I, to construct NO-delivering HDL-like particles (SNO HDL NPs). SNO HDL NPs self-assemble under mild conditions similar to natural processes, avoiding the complex postassembly modification needed for most synthetic NO-release nanoparticles. In vitro data demonstrate that the SNO HDL NPs merge the functional properties of NO and HDL into a targeted nanocarrier. Also, SNO HDL NPs were demonstrated to reduce ischemia/reperfusion injury in vivo in a mouse kidney transplant model and atherosclerotic plaque burden in a mouse model of atherosclerosis. Thus, the synthesis of SNO HDL NPs provides not only a bioinspired nanotherapy for vascular disease but also a foundation to construct diversified multifunctional platforms based on HDL NPs in the future.

Cellular adhesion is regulated by the dynamic ligation process of surface receptors, such as integrin, to adhesive motifs, such as Arg-Gly-Asp (RGD). Remote control of adhesive ligand presentation using external stimuli is an appealing strategy for the temporal regulation of cell-implant interactions in vivo and was recently demonstrated using photochemical reaction. However, the limited tissue penetration of light potentially hampers the widespread applications of this method in vivo. Here, we present a strategy for modulating the nanoscale oscillations of an integrin ligand simply and solely by adjusting the frequency of an oscillating magnetic field to regulate the adhesion and differentiation of stem cells. A superparamagnetic iron oxide nanoparticle (SPION) was conjugated with the RGD ligand and anchored to a glass substrate by a long flexible poly(ethylene glycol) linker to allow the oscillatory motion of the ligand to be magnetically tuned. In situ magnetic scanning transmission electron microscopy and atomic force microscopy imaging confirmed the nanoscale motion of the substrate-tethered RGD-grafted SPION. Our findings show that ligand oscillations under a low oscillation frequency (0.1 Hz) of the magnetic field promoted integrin-ligand binding and the formation and maturation of focal adhesions and therefore the substrate adhesion of stem cells, while ligands oscillating under high frequency (2 Hz) inhibited integrin ligation and stem cell adhesion, both in vitro and in vivo. Temporal switching of the multimodal ligand oscillations between low- and high-frequency modes reversibly regulated stem cell adhesion. The ligand oscillations further induced the stem cell differentiation and mechanosensing in the same frequency-dependent manner. Our study demonstrates a noninvasive, penetrative, and tunable approach to regulate cellular responses to biomaterials in vivo. Our work not only provides additional insight into the design considerations of biomaterials to control cellular adhesion in vivo but also offers a platform to elucidate the fundamental understanding of the dynamic integrin-ligand binding that regulates the adhesion, differentiation, and mechanotransduction of stem cells.

Atherosclerosis is one of the leading causes of morbidity and mortality worldwide. Nanotechnology has provided the possibility of designing nanoparticles that can translocate through tissues and home in to atherosclerotic plaques to achieve desired diagnostic, therapeutic, theranostic or 'theralivery' outcomes. Although nanomedicine approaches have demonstrated exciting possibilities, clinical reality is still distant and challenges are aplenty, such as specificity of targeting and nanotoxicity. Nevertheless, developments in formulations, delivery strategies and experimental models over the coming years will generate new knowledge to define the true potential of this field. This review discusses the most recent developments, current challenges and future possibilities., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Recent developments in scanning probe block copolymer lithography (SPBCL) enable the confinement of multiple metal precursors in a polymer nanoreactor and their subsequent transformation into a single multimetallic heterostructured nanoparticle through thermal annealing. However, the process by which multimetallic nanoparticles form in SPBCL-patterned nanoreactors remains unclear. Here, we utilize the combination of PEO-b-P2VP and Au, Ag, and Cu salts as a model three-component system to investigate this process. The data suggest that the formation of single-component Au, Ag, or Cu nanoparticles within polymer nanoreactors consists of two stages: (I) nucleation, growth, and coarsening of the particles to yield a single particle in each reactor; (II) continued particle growth by depletion of the remaining precursor in the reactor until the particle reaches a stable size. Also, different aggregation rates are observed for single-component particle formation (Au > Ag > Cu). This behavior is also observed for two-component systems, where nucleation sites have greater Au content than the other metals. This information can be used to trap nanoparticles with kinetic structures. High-temperature treatment ultimately facilitates the structural evolution of the kinetic particle into a particle with a fixed structure. Therefore, with multicomponent systems, a third stage that involves elemental redistribution within the particle must be part of the description of the synthetic process. This work not only provides a glimpse at the mechanism underlying multicomponent nanoparticle formation in SPBCL-generated nanoreactors but also illustrates, for the first time, the utility of SPBCL as a platform for controlling the architectural evolution of multimetallic nanoparticles in general.

The vision of nanoscale self-assembly research is the programmable synthesis of macroscale structures with controlled long and short-range order that exhibit a desired set of properties and functionality. However, strategies to reliably isolate and manipulate the nanoscale building blocks based on their size, shape, or chemistry are still in their infancy. Among the promising candidates, DNA-mediated self-assembly has enabled the programmable assembly of nanoparticles into complex architectures. In particular, two-dimensional assembly on substrates has potential for the development of integrated functional devices and analytical systems. Here, we combine the high-resolution patterning capabilities afforded by electron-beam lithography with the DNA-mediated assembly process to enable direct-write grayscale DNA density patterning. This method allows modulation of the functionally active DNA surface density to control the thermodynamics of interactions between nanoparticles and the substrate. We demonstrate that size-selective directed assembly of nanoparticle films from solutions containing a bimodal distribution of particles can be realized by exploiting the cooperativity of DNA binding in this system. To support this result, we study the temperature-dependence of nanoparticle assembly, analyze the DNA damage by X-ray photoelectron spectroscopy and fluorescence microscopy, and employ molecular dynamics simulations to explore the size-selection behavior.

Field effect transistors using ultrathin molybdenum disulfide (MoS(2)) have recently been experimentally demonstrated, which show promising potential for advanced electronics. However, large variations like hysteresis, presumably due to extrinsic/environmental effects, are often observed in MoS(2) devices measured under ambient environment. Here, we report the origin of their hysteretic and transient behaviors and suggest that hysteresis of MoS(2) field effect transistors is largely due to absorption of moisture on the surface and intensified by high photosensitivity of MoS(2). Uniform encapsulation of MoS(2) transistor structures with silicon nitride grown by plasma-enhanced chemical vapor deposition is effective in minimizing the hysteresis, while the device mobility is improved by over 1 order of magnitude.

Thermoelectric materials can directly generate electrical power from waste heat but the challenge is in designing efficient, stable and inexpensive systems. Nanostructuring in bulk materials dramatically reduces the thermal conductivity but simultaneously increases the charge carrier scattering, which has a detrimental effect on the carrier mobility. We have experimentally achieved concurrent phonon blocking and charge transmitting via the endotaxial placement of nanocrystals in a thermoelectric material host. Endotaxially arranged SrTe nanocrystals at concentrations as low as 2% were incorporated in a PbTe matrix doped with Na(2)Te. This effectively inhibits the heat flow in the system but does not affect the hole mobility, allowing a large power factor to be achieved. The crystallographic alignment of SrTe and PbTe lattices decouples phonon and electron transport and this allows the system to reach a thermoelectric figure of merit of 1.7 at ~800 K.

Nanoparticles with high-index facets are intriguing because such facets can lend the structure useful functionality, including enhanced catalytic performance and wide-ranging optical tunability. Ligand-free solid-state syntheses of high index-facet nanoparticles, through an alloying-dealloying process with foreign volatile metals, are attractive owing to their materials generality and high yields. However, the role of foreign atoms in stabilizing the high-index facets and the dynamic nature of the transformation including the coarsening and facet regulation process are still poorly understood. Herein, the transformation of Pt salts to spherical seeds and then to tetrahexahedra, is studied in situ via gas-cell transmission electron microscopy. The dynamic behaviors of the alloying and dealloying process, which involves the coarsening of nanoparticles and consequent facet regulation stage are captured in the real time with a nanoscale spatial resolution. Based on additional direct evidence obtained using atom probe tomography and density functional theory calculations, the underlying mechanisms of the alloying-dealloying process are uncovered, which will facilitate broader explorations of high-index facet nanoparticle synthesis. Faceted nanoparticles with high-index planes exposed usually bear promising material functionalities. Here, the authors directly observe the coarsening and facet regulation process of tetrahexahedra Pt nanoparticles by using in-situ gas-phase TEM. [ABSTRACT FROM AUTHOR]

Corrosion is a significant problem for the stability of structural metals and potentially for functional nanomaterials in operating environments. When two metals with different electrochemical potentials form a junction, galvanic corrosion occurs, resulting in the sacrificial dissolution of the metal with a higher oxidation potential (lower electrode potential). Here, it is shown that bimetallic hetero‐nanostructures composed of phase‐segregated metals undergo galvanic corrosion in aqueous environments. Such selective etching of the sacrificial metal in heterojunction particles leads to the formation of unusual and kinetically stabilized half‐spheroid particles. By using a fluid cell and in situ scanning transmission electron microscopy, a two‐stage corrosion process can be observed where the Cu experiences a fractal breakdown before the Ag corrodes due to the lack of a protective oxide layer. However, when treated with a mild Ar plasma, the stability of these structures against corrosion is enhanced due to the conversion of the amorphous native oxide to a denser, thin layer of CuO on the Cu surface. Taken together, this work highlights the importance of considering the effects of galvanic corrosion on the stability of multicomponent nanoparticles, and it shows how mass transport in a nanoscale system is influenced by redox processes. [ABSTRACT FROM AUTHOR]

Multicomponent nanoparticles can be synthesized with either homogeneous or phase-segregated architectures depending on the synthesis conditions and elements incorporated. To understand the parameters that determine their structural fate, multicomponent metal-oxide nanoparticles consisting of combinations of Co, Ni, and Cu were synthesized by using scanning probe block copolymer lithography and characterized using correlated electron microscopy. These studies revealed that the miscibility, ratio of the metallic components, and the synthesis temperature determine the crystal structure and architecture of the nanoparticles. A Co-Ni-O system forms a rock salt structure largely owing to the miscibility of CoO and NiO, while Cu-Ni-O, which has large miscibility gaps, forms either homogeneous oxides, heterojunctions, or alloys depending on the annealing temperature and composition. Moreover, a higher-ordered structure, Co-Ni-Cu-O, was found to follow the behavior of lower ordered systems. [ABSTRACT FROM AUTHOR]

The incorporation of nanostructured carbon has been recently reported as an effective approach to improve the cycling stability when Si is used as high-capacity anodes for the next generation Li-ion battery. However, the mechanism of such notable improvement remains unclear. Herein, we report in-situ transmission electron microscopy (TEM) studies to directly observe the dynamic electrochemical lithiation/delithiation processes of crumpled graphene-encapsulated Si nanoparticles to understand their physical and chemical transformations. Unexpectedly, in the first lithiation process, crystalline Si nanoparticles undergo an isotropic to anisotropic transition, which is not observed in pure crystalline and amorphous Si nanoparticles. Such a surprising phenomenon arises from the uniformly distributed localized voltage around the Si nanoparticles due to the highly conductive graphene sheets. It is observed that the intimate contact between graphene and Si is maintained during volume expansion/contraction. Electrochemical sintering process where small Si nanoparticles react and merge together to form large agglomerates following spikes in localized electric current is another problem for batteries. In-situ TEM shows that graphene sheets help maintain the capacity even in the course of electrochemical sintering. Such in-situ TEM observations provide valuable phenomenological insights into electrochemical phenomena, which may help optimize the configuration for further improved performance [ABSTRACT FROM AUTHOR]

Proposes a multistep technique for the generation of metallic/alloy nanoparticles coated with amorphous silica. Factors that affect the performance and properties of nanoparticles; Materials that may be used to form silica coatings on nanoparticles; Description of an apparatus used to produce silica-coated magnetic nanoparticles; Functions of amorphous silica coating.

Microcantilevers are used to detect DNA strands with a specific sequence using gold nanoparticle modified DNA. The hybridization reactions lead to the attachment of gold nanoparticles. After the amplification process by catalyzing the nucleation of silver, the shift of the cantilever frequency signals the binding events. The method can detect target DNA at a concentration of 0.05 nM or lower. Combined with stringency washing, a single base pair mismatched DNA strand can be discriminated. The cantilever is 1/100 times smaller than its macroscopic counterpart (quartz crystal microbalance), and can be mass produced as miniaturized sensor arrays by current processing technology. Multiple DNA detection is possible by coating multiple cantilevers with various capture DNA strands and monitoring the change in their resonance frequencies. [ABSTRACT FROM AUTHOR]

A correction to the article "Dynamics of Electrochemical Lithiation/Delithiation of Graphene-Encapsulated Silicon Nanoparticles Studied by In-situ TEM" that was published in the January 24, 2014 issue is presented.

Tetrahexahedral particles (~10 to ~500 nanometers) composed of platinum (Pt), palladium, rhodium, nickel, and cobalt, as well as a library of bimetallic compositions, were synthesized on silicon wafers and on catalytic supports by a ligand-free, solid-state reaction that used trace elements [antimony (Sb), bismuth (Bi), lead, or tellurium] to stabilize high-index facets. Both simulation and experiment confirmed that this method stabilized the {210} planes. A study of the PtSb system showed that the tetrahexahedron shape resulted from the evaporative removal of Sb from the initial alloy—a shape-regulating process fundamentally different from solution-phase, ligand-dependent processes. The current density at a fixed potential for the electro-oxidation of formic acid with a commercial Pt/carbon catalyst increased by a factor of 20 after transformation with Bi into tetrahexahedral particles. [ABSTRACT FROM AUTHOR]

Nanomaterials that form as heterostructures have applications in catalysis, plasmonics, and electronics. Multielement nanoparticles can now be synthesized through a variety of routes, but how thermodynamic phases form in such structures and how specific interfaces between them can be designed and synthesized are still poorly understood. We explored how palladium-tin alloys form mixed-composition phases with metals with known but complex miscibilities. Nanoparticles with up to seven elements were synthesized, and many form triphase heterostructures consisting of either three-interface or two-interface architectures. Density functional theory calculations and experimental work were used to determine the balance between the surface and interfacial energies of the observed phases. From these observations, design rules have been established for making polyelemental systems with specific heterostructures, including tetraphase nanoparticles with as many as six junctions. [ABSTRACT FROM AUTHOR]

We have prepared nanocrystals of MoS2 across a range of length scales by heating single crystals of the molecular precursor (NH4)2Mo3S13·H2O. Rod-shaped crystals of the polysulfide precursor retain their original morphology after heating at temperatures up to 1000 °C and undergo complete conversion to MoS2 while acting as a template for the confined formation of MoS2 nanocrystals. This solid state transformation proceeds with the release of gaseous species without blowing the crystals apart and leads to formation of pores embedded into a nanocrystalline assembly of the templated nano-MoS2. The obtained assemblies of MoS2 nanocrystals have the exact same shape of the original rod-shaped (NH4)2Mo3S13·H2O crystals indicative of a pseudomorphic shape-retentive process. Such crystal-shaped nanocrystal assemblies show electrical conductivity values similar to a bulk MoS2 single crystal with electron carrier concentration of 1.5 × 1014 cm–3 and mobility of 7 cm2/(V s). The nanocrystals of MoS2 were grown at temperatures ranging from 450 to 1000 °C, and the sizes, shapes, morphologies, and their orientations can be engineered as a function of heating rate, soaking time, and temperature. These findings suggest a unique process for constrained templated nanocrystal growth from an organized molecular precursor structure with control of bulk morphology, size distribution, and orientation of nanocrystallites. [ABSTRACT FROM AUTHOR]

Multiplexed surface encoding is achieved by positioning two different sizes of gold nanocubes on gold surfaces with precisely defined locations for each particle via template-confined, DNA-mediated nanoparticle assembly. As a proof-of-concept demonstration, cubes with 86 and 63 nm edge lengths are assembled into arrangements that physically and spectrally encrypt two sets of patterns in the same location. These patterns can be decrypted by mapping the absorption intensity of the substrate at λ = 773 and 687 nm, respectively. This multiplexed encoding platform dramatically increases the sophistication and density of codes that can be written using colloidal nanoparticles, which may enable high-security, high-resolution encoding applications. [ABSTRACT FROM AUTHOR]

DNA programmable assembly has been combined with top-down lithography to construct superlattices of discrete, reconfigurable nanoparticle architectures on a gold surface over large areas. Specifically, the assembly of individual colloidal plasmonic nanoparticles with different shapes and sizes is controlled by oligonucleotides containing “locked” nucleic acids and confined environments provided by polymer pores to yield oriented architectures that feature tunable arrangements and independently controllable distances at both nanometer- and micrometer-length scales. These structures, which would be difficult to construct by other common assembly methods, provide a platform to systematically study and control light-matter interactions in nanoparticle-based optical materials. The generality and potential of this approach are explored by identifying a broadband absorber with a solvent polarity response that allows dynamic tuning of visible light absorption. [ABSTRACT FROM AUTHOR]

DNA surface ligands can be used as programmable "bonds" to control the arrangement of nanoparticles into crystalline superlattices. Here, we study the intrinsic responsiveness of these DNA bonds to changes in local dielectric constant (εr) as a new approach to dynamically modulate superlattice structure. Remarkably, ethanol (EtOH) addition can be used to controllably tune DNA bond length from 16 to 3 nm and to increase bond stability by >40 °C, while retaining long-range order and crystal habit. Interestingly, we find that these structural changes, which involve the expansion and contraction of crystals by up to 75% in volume, occur in a cooperative fashion once a critical percentage of EtOH is reached. These results provide a facile and robust approach to create stimuli-responsive lattices, to access high volume fractions, and to improve thermal stability. [ABSTRACT FROM AUTHOR]

Multimetallic nanoparticles are useful in many fields, yet there are no effective strategies for synthesizing libraries of such structures, in which architectures can be explored in a systematic and site-specific manner.The absence of these capabilities precludes the possibility of comprehensively exploring such systems.We present systematic studies of individual polyelemental particle systems, in which composition and size can be independently controlled and structure formation (alloy versus phase-separated state) can be understood.We made libraries consisting of every combination of five metallic elements (Au, Ag,Co, Cu, and Ni) through polymer nanoreactor-mediated synthesis. Important insight into the factors that lead to alloy formation and phase segregation at the nanoscale were obtained, and routes to libraries of nanostructures that cannot be made by conventional methods were developed. [ABSTRACT FROM AUTHOR]

Alloy nanoparticles are important in many fields, including catalysis, plasmonics, and electronics, due to the chemical and physical properties that arise from the interactions between their components. Typically, alloy nanoparticles are made by solution-based synthesis; however, scanning-probe-based methods offer the ability to make and position such structures on surfaces with nanometer-scale resolution. In particular, scanning probe block copolymer lithography (SPBCL), which combines elements of block copolymer lithography with scanning probe techniques, allows one to synthesize nanoparticles with control over particle diameter in the 2-50 nm range. Thus far, single-element structures have been studied in detail, but, in principle, one could make a wide variety of multicomponent systems by controlling the composition of the polymer ink, polymer feature size, and metal precursor concentrations. Indeed, it is possible to use this approach to synthesize alloy nanoparticles comprised of combinations of Au, Ag, Pd, Ni, Co, and Pt. Here, such structures have been made with diameters deliberately tailored in the 10-20 nm range and characterized by STEM and EDS for structural and elemental composition. The catalytic activity of one class of AuPd alloy nanoparticles made via this method was evaluated with respect to the reduction of 4-nitrophenol with NaBH4. In addition to being the first catalytic studies of particles made by SPBCL, these proof-of-concept experiments demonstrate the potential for SPBCL as a new method for studying the fundamental science and potential applications of alloy nanoparticles in areas such as heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

We have investigated the possible mechanisms of phonon scattering by nanostructures and defects in PbTe-X (X = 2% Sb, Bi, or Pb) thermoelectric materials systems. We find that among these three compositions, PbTe-2% Sb has the lowest lattice thermal conductivity and exhibits a larger strain and notably more misfit dislocations at the precipitate/PbTe interfaces than the other two compositions. In the PbTe-Bi 2% sample, we infer some weaker phonon scattering BiTe precipitates, in addition to the abundant Bi nanostructures. In the PbTe-Pb 2% sample, we also find that pure Pb nanoparticles exhibit stronger phonon scattering than nanostructures with Te vacancies. Within the accepted error range, the theoretical calculations of the lattice thermal conductivity in the three systems are in close agreement with the experimental measurements, highlighting the important role of misfit dislocations, nanoscale particles, and associated interfacial elastic strain play in phonon scattering. We further propose that such particle-induced local elastic perturbations interfere with the phonon propagation pathway, thereby contributing to further reduction in lattice thermal conductivity, and consequently can enhance the overall thermoelectric figure of merit. [ABSTRACT FROM AUTHOR]

Abstract: Core–shell nanoparticles have emerged as an important class of functional nanostructures with potential applications in many diverse fields, especially in health sciences. We have used a modified aqueous sol–gel route for the synthesis of size-selective FePt@SiO2 core–shell nanoparticles. In this approach, oleic acid and olyel amine stabilized FePt nanoparticles are first encapsulated through an aminopropoxysilane (APS) monolayer and then subsequent condensation of triethoxysilane (TEOS) on FePt particle surface. These well-defined FePt@SiO2 core–shell nanoparticles with narrow size distribution become colloidal in aqueous media, and can thus be used as carrier fluid for biomolecular complexes. In comparison, the scarce hydrophilic nature of oleic acid monolayers on FePt particle surface yields an edgy partial coating of silica when only TEOS is applied for the surface modification. The synthesized core–shell nanoparticles were characterized by direct techniques of high resolution transmission electron microscopy (HRTEM), EDS and indirectly via UV–vis absorption and FTIR studies. The FePt@SiO2 nanoparticles exhibit essential characteristics of superparamagnetic behavior, as investigated by SQUID magnetometry. The blocking temperatures (T B) of FePt and FePt@SiO2 (135 and 80 K) were studied using zero field cooled (ZFC)/field cooled (FC) curves. [Copyright &y& Elsevier]