Versatile Nanoparticles Research Articles

Facile synthesis of lanthanide nanoparticles with paramagnetic, down- and up-conversion properties

Lanthanide materials play an important role in biomedical researches, among which paramagnetic, down- and up-conversion lanthanide nanoparticles are of particular interest. However, little effort has been made to develop versatile lanthanide nanoparticles with these properties combined in a single particle. Herein, we present a facile strategy to make multifunctional lanthanide nanoparticles by doping sensitized lanthanide complexes into porous silica coated on up-conversion NaYF(4) nanocrystals. The nanoparticles not only show strong down- and up-conversion fluorescence but also exhibit high magnetic resonance properties.

Nanoparticle assembly by confinement in wrinkles: experiment and simulations

We created hierarchically ordered structures of nanoparticles on smooth planar hydrophilic substrates by drying colloidal dispersions in confinement under macroscopic stamps with microscopically wrinkled surfaces. Experiments were carried out with model nanoparticle suspensions that possess high colloidal stability and monodispersity. The structures ranged from single parallel lines of particles to arrays of dense prismatic ridges. The type of observed structure could be controlled by the particle concentration in the initial dispersion. Confinement between two crossed stamps led to interconnected meshes of particles. The precise morphology could be predicted in all cases by Monte Carlo computer simulations of confined hard spheres. Our findings open up possibilities for versatile nanoparticle assembly on surfaces.

Uniform Mesoporous Dye-Doped Silica Nanoparticles Decorated with Multiple Magnetite Nanocrystals for Simultaneous Enhanced Magnetic Resonance Imaging, Fluorescence Imaging, and Drug Delivery

Highly versatile nanocomposite nanoparticles were synthesized by decorating the surface of mesoporous dye-doped silica nanoparticles with multiple magnetite nanocrystals. The superparamagnetic property of the magnetite nanocrystals enabled the nanoparticles to be used as a contrast agent in magnetic resonance (MR) imaging, and the dye molecule in the silica framework imparted optical imaging modality. Integrating a multitude of magnetite nanocrystals on the silica surface resulted in remarkable enhancement of MR signal due to the synergistic magnetism. An anticancer drug, doxorubicin (DOX), could be loaded in the pores and induced efficient cell death. In vivo passive targeting and accumulation of the nanoparticles at the tumor sites was confirmed by both T2 MR and fluorescence imaging. Furthermore, apoptotic morphology was clearly detected in tumor tissues of mice treated with DOX loaded nanocomposite nanoparticles, demonstrating that DOX was successfully delivered to the tumor sites and its anticancer activity was retained.

Wet Synthesis of Copper Oxide Nanopowder

ABSTRACT A simple and efficient synthesis of cuprous oxide and cupric oxide nanoparticles was carried out with controlled surface properties via soft chemistry approach. The monodisperse and versatile Cu2O and CuO nanoparticles were characterized with the help of FT-IR, UV-Vis, TGA/DSC, XRD, SEM-EDX, TEM, and BET. From the XRD analysis, the size of Cu2O and CuO nanoparticles were calculated as 31 nm and 32 nm, respectively, which is calculated with the help of Scherer equation, as supported by TEM. The morphology of the nanoparticles can be controlled by tuning the amount of KOH and nature of solvent. Chemie douce approach is a novel, cheap, and convenient technique suitable for industrial production.

A Nonadjuvanted Polypeptide Nanoparticle Vaccine Confers Long-Lasting Protection against Rodent Malaria

We have designed and produced a prototypic malaria vaccine based on a highly versatile self-assembling polypeptide nanoparticle (SAPN) platform that can repetitively display antigenic epitopes. We used this platform to display a tandem repeat of the B cell immunodominant repeat epitope (DPPPPNPN)(2)D of the malaria parasite Plasmodium berghei circumsporozoite protein. Administered in saline, without the need for a heterologous adjuvant, the SAPN construct P4c-Mal conferred a long-lived, protective immune response to mice with a broad range of genetically distinct immune backgrounds including the H-2(b), H-2(d), and H-2(k) alleles. Immunized mice produced a CD4(+) T cell-dependent, high-titer, long-lasting, high-avidity Ab response against the B cell epitope. Mice were protected against an initial challenge of parasites up to 6 mo after the last immunization or for up to 15 mo against a second challenge after an initial challenge of parasites had successfully been cleared. Furthermore, we demonstrate that the SAPN platform not only functions to deliver an ordered repetitive array of B cell peptide epitopes but operates as a classical immunological carrier to provide cognate help to the P4c-Mal-specific B cells.

Versatile Strategy for Precisely Tailored Core@Shell Nanostructures with Single Shell Layer Accuracy: The Case of Metallic Shell

We report a general well-controlled synthetic strategy to achieve meticulous control of metallic shell growth at the single monolayer level with versatile core nanoparticles, thus facilitating investigation of their scope for numerous applications. The central component of this strategy is to introduce an intermediate phase in a phase transfer reaction to finely tune shell growth process. Two different typed core nanoparticles with distinct functionality and surface chemistry, including metallic and semiconductor nanoparticles, are chosen to demonstrate versatility of our approach. Enabled by such, we further highlight importance and tunability of plasmonic and optical couplings with layer-by-layer shell control. Thus, our strategy should be important for understanding and manipulating fundamental nanoscale chemical and physical property as well as assembling nanostructures with desirable structure and functionality.

Quantum Dots and Their Potential Biomedical Applications in Photosensitization for Photodynamic Therapy

Semiconductor quantum dots have received considerable interest in recent years as a result of their unique optical properties, leading to many applications in biology. This review examines their potential for photosensitization in photodynamic therapy compared with, and in combination with, conventional photosensitizing organic dyes. Photodynamic therapy is used for treating a range of malignant tumors and certain non-malignant pathologies, and conventional photosensitizers are based on organic dyes that are efficient generators of cytotoxic reactive oxygen species. By exploiting the unique optical properties of quantum dots, the conjugation of quantum dots with photosensitizers and targeting agents could provide a new class of versatile multifunctional nanoparticles for both diagnostic imaging and therapeutic applications.

Multifunctional Inorganic Nanoparticles for Imaging, Targeting, and Drug Delivery

Drug delivery, magnetic resonance and fluorescence imaging, magnetic manipulation, and cell targeting are simultaneously possible using a multifunctional mesoporous silica nanoparticle. Superparamagnetic iron oxide nanocrystals were encapsulated inside mesostructured silica spheres that were labeled with fluorescent dye molecules and coated with hydrophilic groups to prevent aggregation. Water-insoluble anticancer drugs were delivered into human cancer cells; surface conjugation with cancer-specific targeting agents increased the uptake into cancer cells relative to that in non-cancerous fibroblasts. The highly versatile multifunctional nanoparticles could potentially be used for simultaneous imaging and therapeutic applications.

Compact Cysteine-Coated CdSe(ZnCdS) Quantum Dots for in Vivo Applications

We have developed a versatile nanoparticle construct using a compact cysteine coating on a CdSe(ZnCdS) core(shell) nanocrystal (QD-Cys) that is biologically compatible, exceptionally compact, highly fluorescent, and easily functionalized. The small hydrodynamic diameter of QD-Cys ( approximately 6 nm) allows for renal clearance of these nanoparticles in rat models. Moreover, the ability to directly conjugate to QD-Cys opens up the possibility of functionalized nanocrystals for in vivo targeted imaging, in which small targeting molecules can be appended to QD-Cys, and unbound QDs can be rapidly cleared to achieve high signal/noise ratios and to reduce background toxicity.

Immobilization of Bioactive Fibroblast Growth Factor-2 into Cubic Proteinous Microcrystals (Bombyx mori Cypovirus Polyhedra) That Are Insoluble in a Physiological Cellular Environment

The supramolecular architecture of the extracellular matrix and the disposition of its specific accessory molecules give rise to variable heterotopic signaling cues for single cells. Here we have described the successful occlusion of human fibroblast growth factor-2 (FGF-2) into the cubic inclusion bodies (FGF-2 polyhedra) of the Bombyx mori cytoplasmic polyhedrosis virus (BmCPV). The polyhedra are proteinous cubic crystals of several microns in size that are insoluble in the extracellular milieu. Purified FGF-2 polyhedra were found to stimulate proliferation and phosphorylation of p44/p42 mitogen-activated protein kinase in cultured fibroblasts. Moreover, cellular responses were blocked by a synthetic inhibitor of the FGF signaling pathway, SU5402, suggesting that FGF-2 polyhedra indeed act through FGF receptors. Furthermore, FGF-2 polyhedra retained potent growth stimulatory properties even after desiccation. We have demonstrated that BmCPV polyhedra microcrystals that occlude extracellular signaling proteins are a novel and versatile tool that can be employed to analyze cellular behavior at the single cell level.

Nanovehicles Based Bioassay Labels

AbstractIn this article, we review recent advances of our group in nanoparticle labels based bioassay. Apoferritin and silica nanoparticles have been used as nanovehicles to load large amount of markers for highly sensitive bioassay. Markers loaded apoferritin, apoferritin‐templated metallic phosphate nanoparticles, and poly[guanine] coated silica nanoparticles have been prepared, characterized and used as labels for highly sensitive bioassay of protein and DNA. Dissociation and reconstitution characteristics at different pH as well as the special cavity structure of apoferritin nanovehicle provides a simple and convenient route to prepare versatile nanoparticle labels and avoid the complicated and tedious synthesis process of conventional nanoparticle labels. The optical and electrochemical characteristics of the prepared nanoparticle labels are easily controlled by loading different optical or electrochemical markers. Additionally, the use of apoferritin nanovehicle as template for synthesis of metallic phosphate nanoparticle labels offers fast route to prepare uniform‐size metallic nanoparticle labels for electrochemical bioassay and avoids the traditional harsh dissolution conditions to dissolve metallic nanoparticle tags (that is, the strong‐acid dissolution of quantum dots and gold nanoparticles) during the stripping analysis step. Silica nanoparticle has also been used as nanovehicle to carry thousands of poly[guanine] tracers, which was used to enhance the oxidation current of Ru(bpy)$\rm{ {_{3}^{2+}}}$, resulting in enhanced sensitivity of electrochemical immunoassay. The new nanovehicle‐based labels have been used for highly sensitive electrochemical detection of DNA and protein biomarkers, such as tumor necrosis factor‐alpha (TNF‐α). The high sensitivity and selectivity make these labels a useful addition to the armory of nanoparticle‐based bioassay. The new nanovehicles based labels hold great promise for multiplex protein and DNA detection and for enhancing the sensitivity of other bioassays.

The molecular organization of cypovirus polyhedra

Cypoviruses and baculoviruses are notoriously difficult to eradicate because the virus particles are embedded in micrometre-sized protein crystals called polyhedra. The remarkable stability of polyhedra means that, like bacterial spores, these insect viruses remain infectious for years in soil. The environmental persistence of polyhedra is the cause of significant losses in silkworm cocoon harvests but has also been exploited against pests in biological alternatives to chemical insecticides. Although polyhedra have been extensively characterized since the early 1900s, their atomic organization remains elusive. Here we describe the 2 A crystal structure of both recombinant and infectious silkworm cypovirus polyhedra determined using crystals 5-12 micrometres in diameter purified from insect cells. These are the smallest crystals yet used for de novo X-ray protein structure determination. We found that polyhedra are made of trimers of the viral polyhedrin protein and contain nucleotides. Although the shape of these building blocks is reminiscent of some capsid trimers, polyhedrin has a new fold and has evolved to assemble in vivo into three-dimensional cubic crystals rather than icosahedral shells. The polyhedrin trimers are extensively cross-linked in polyhedra by non-covalent interactions and pack with an exquisite molecular complementarity similar to that of antigen-antibody complexes. The resulting ultrastable and sealed crystals shield the virus particles from environmental damage. The structure suggests that polyhedra can serve as the basis for the development of robust and versatile nanoparticles for biotechnological applications such as microarrays and biopesticides.

Properties of a Versatile Nanoparticle Platform Contrast Agent To Image and Characterize Atherosclerotic Plaques by Magnetic Resonance Imaging

The need for more specific and selective contrast agents for magnetic resonance imaging motivated us to prepare a new nanoparticle agent based on high-density lipoproteins (HDL). This second generation contrast agent can be prepared in three different ways. The HDL nanoparticles (rHDL) were fully characterized by FPLC and gel electrophoresis. The flexibility of the platform also allows us to incorporate optical probes into rHDL for localization ex vivo by confocal fluorescence microscopy. The contrast-agent-containing nanoparticles were injected into mice that develop atherosclerotic lesions. Magnetic resonance imaging of the animals showed clear enhancement of the atherosclerotic plaques.

Versatile Glycoblotting Nanoparticles for High‐Throughput Protein Glycomics

We have developed an effective and practical trap-and-release method based on chemoselective ligation of carbohydrates with reactive aminooxyl groups attached to the surface of nanoparticles (referred to as glycoblotting nanoparticles). These glycoblotting nanoparticles were synthesized by UV irradiation of diacetylene-functionalized lipids that contain the aminooxyl group. The glycoblotting nanoparticles captured carbohydrates in aqueous solution under mild conditions and were collected by simple centrifugation. The trapped carbohydrates were effectively released from the nanoparticles under acidic conditions to give pure oligosaccharides. This glycoblotting process reduced the time required for the purification process of carbohydrates to less than 6 h, compared to the several days needed for conventional chromatographic techniques. The oligosaccharides (N-glycan) were released from ovalbumin (glycoprotein) by PNGase F after tryptic digestion. MALDI-TOF mass spectra before purification did not show any significant signals corresponding to N-glycans because these signals were hidden by the large signals of the abundant peptides. However, after purification with the glycoblotting nanoparticles, only signals corresponding to oligosaccharides appeared. We also demonstrated a clear analysis of the oligosaccharides contained in the mice dermis by means of glycoblotting.

Electrochemical deposition of metal nanoparticles functionalized with multiple redox molecules

The electrodeposition of metal nanoparticles, the surface of which was functionalized with multiple redox species, biferrocene (BFc) or anthraquinone (AQ) thiol derivatives, proceeded to construct a redox-active metal nanoparticle film on an electrode. The investigation of this deposition mechanism was carried out with electrochemical (CV, EQCM) and spectroscopic (UV–Vis) measurements, elemental analysis (ICP, PGA), and surface observations of the formed films (STM, AFM). It was demonstrated that this system could be utilized as a novel method for fabricating versatile metal nanoparticle films comprised of multiple layers by changing parameters in the deposition process such as the solvent, core element, and core size. The specific spectroscopic properties of the prepared films induced by particle-particle interactions different from those induced by isolated particles are also discussed herein. To cite this article: M. Yamada, H. Nishihara, C. R. Chimie 6 (2003).

Solid Solution Formation in Amphiphilic Organic−Inorganic Clay Heterostructures

Amphiphilic mixed ion smectite clays have been prepared by the reaction of inorganic ion exchanged forms of synthetic fluorohectorite with [C16H33EBu3+] onium ions, where E is N or P. Regardless of the initial inorganic exchange cation (Li+, Na+, Ca2+, Ba2+, Al3+, Ce3+), heterostructures with regularly stacked galleries of organic and inorganic ions were formed at fQ = 0.50, where fQ is the fraction of surfactant onium ions. The stagelike segregation of cations into separate galleries is attributable to the steric restrictions of the headgroup and to hydrophobic interactions between the alkyl groups of the onium ions. The same 1:1 mixed ion intercalates were formed by ion redistribution reactions of the homoionic end-member clays, indicating their thermodynamic stability. Decreasing the fraction of onium ions from fQ = 0.50 to 0.33 resulted in the displacement of up to 30% of the onium ions (C16H33PBu3+) in the organic galleries by inorganic cations (Na+). The same gallery stacking sequence as in a 1:1 mixed ion heterostructure was observed, signifying that up to 30% of the onium ions in the organic galleries can be replaced by inorganic cations to form solid solutions. This alloylike mixing of gallery organic and inorganic ions appears to be unique among metal oxide intercalation compounds. Phase segregation of the parent end-member clays was observed at compositions outside the heterostructure composition range. By combining the hydrophobic and hydrophilic properties of organic and inorganic clays into a single heterostructured phase, we expect these amphiphilic materials to find applications as versatile ion exchangers, sorbents, and nanoparticle reagents.