Homogeneous conjugation of peptides onto gold nanoparticles enhances macrophage response

Inhibition of HSV-1 attachment, entry, and cell-to-cell spread by functionalized multivalent gold nanoparticles

The use of modified nanoparticles in interactions with biological targets is attracting rapidly increasing attention. In this Full Paper, the application of gold nanoparticles capped with mercaptoethanesulfonate (Au-MES NPs) as effective inhibitors of Herpes simplex virus type 1 infection based on their ability to mimic cell-surface-receptor heparan sulfate is described. Mechanistic studies reveal that Au-MES NPs interfere with viral attachment, entry, and cell-to-cell spread, thereby preventing subsequent viral infection in a multimodal manner. The ligand multiplicity achieved with carrier nanoparticles is crucial in generating polyvalent interactions with the virus at high specificity, strength, and efficiency. Such multivalent-nanoparticle-mediated inhibition is a promising approach for alternative antiviral therapy.

Shape-dependent cytotoxicity and proinflammatory response of poly(3,4-ethylenedioxythiophene) nanomaterials

Poly(3,4-ethylenedioxythiophene) (PEDT) is recognized as one of the most promising conducting polymers for future applications in the fields of electronics, optics, energy storage/conversion, and biomedical science. The toxicity of PEDT could be considered to affect the potential for its widespread application. Herein, the cytotoxicity and proinflammatory response of PEDT nanomaterials of three different shapes toward human lung fibroblast (IMR90) and mouse alveolar macrophage (J774A.1) cells are investigated. The shape-dependent toxicity of the PEDT nanomaterials is evaluated by examining cell morphological change, cytotoxicity, apoptosis/necrosis, oxidative stress, and immune response. The cytotoxicity and apoptosis of the nanomaterials increase with their decreasing aspect ratio in both cell lines. The formation of reactive oxygen species in cells treated with PEDT nanomaterials is dependent on the shape and concentration of the nanomaterial. Proinflammatory cytokines, such as interleukin-1, interleukin-6, and tumor necrosis factor alpha from macrophages, are induced by PEDT nanomaterial-treated cells.

Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles

Inorganic colloidal nanoparticles are very small, nanoscale objects with inorganic cores that are dispersed in a solvent. Depending on the material they consist of, nanoparticles can possess a number of different properties such as high electron density and strong optical absorption (e.g. metal particles, in particular Au), photoluminescence in the form of fluorescence (semiconductor quantum dots, e.g. CdSe or CdTe) or phosphorescence (doped oxide materials, e.g. Y(2)O(3)), or magnetic moment (e.g. iron oxide or cobalt nanoparticles). Prerequisite for every possible application is the proper surface functionalization of such nanoparticles, which determines their interaction with the environment. These interactions ultimately affect the colloidal stability of the particles, and may yield to a controlled assembly or to the delivery of nanoparticles to a target, e.g. by appropriate functional molecules on the particle surface. This work aims to review different strategies of surface modification and functionalization of inorganic colloidal nanoparticles with a special focus on the material systems gold and semiconductor nanoparticles, such as CdSe/ZnS. However, the discussed strategies are often of general nature and apply in the same way to nanoparticles of other materials.

Synthesis of platinum cubes, polypods, cuboctahedrons, and raspberries assisted by cobalt nanocrystals

The introduction of metallic traces into the synthesis of platinum nanocrystals (Pt NCs) has been investigated as a surfactant-independent means of controlling shape. Various nanocrystal morphologies have been produced without modification of the reaction conditions, composition, and concentration other than the presence of cobalt traces (<5%). In the presence of metallic cobalt (a strong reducer for Pt cations) cubic Pt NCs are obtained, while cobalt ions or gold NCs have no effect on the synthesis, and as a result, polypods are obtained. Intermediate shapes such as cemented cubes or cuboctahedron NCs are also obtained under similar conditions. Thus, various NC shapes can be obtained with subtle changes, which illustrates the high susceptibility and mutability of the NC shape to modification of the reaction kinetics during the early reduction process. Our studies help progress toward a general mechanism for nanocrystal shape control.

The collective behavior of nanoscale building blocks

Nanotechnology has reached the stage of development where the subject of most investigations is not individual nanoparticles or nanowires but rather systems of much greater complexity.