Functionalization Of Metal Nanoparticles Research Articles

Review on nanoparticles used in drug delivery for cancer

Current cancer treatments include surgical intervention, radiation, and chemotherapy medications. Nanoparticles have a variety of advantages as medication delivery systems. Nanoparticles (NPs) are newly discovered methods for delivering medicines to tumour cells with little drug leakage into healthy cells. To enhance biodistribution and increase circulation duration in the bloodstream, nanoparticles have been developed with optimum size and surface properties. Here, I look at the many types and features of nanoparticles. Examples of commercially available nanocarrier-based medicines include: Therapeutic nanoparticles, the function of metal nanoparticles in cancer diagnosis and therapy, are important ideas in nanoparticle medication delivery for cancer.

Silver and Gold Nanoparticles Functionalized with Naphthalene Diimide

Functionalization of metal nanoparticles with surface ligands effects their growth, shape and size as well as the optical and electronic properties. The change of optical property of the nanoparticles due to their surface ligand is an important field of nanoparticles application. Here we repot functionalization and characterization of metal nanoparticles with redox active naphthalene diimide (NDI). Silver neodecanoate and gold (I) sodium thiosulfate were used to synthesize silver and gold nanoparticles respectively, in presence of DPA-NDI-SH (where DPA = diphenylamine) in a single reaction vessel. Dimethyl sulfoxide (DMSO) and dimethyl formamide (DMF) were used as both solvent and reducing agent for Ag and Au nanoparticles, respectively. Analyses by XRD, TEM and FT-IR indicated well dispersed naphthalene diimide coated nanoparticles. Also the optical properties of the nanoparticles showed a red shift of plasmon band due to charge transfer between surface molecule and core structure interface. On the basis of this optical property, these hybrid nanostructure could be useful to design nano optoelectronic devices.

Improvement of Toluene-Sensing Performance of SnO₂ Nanofibers by Pt Functionalization.

Functionalization of metal nanoparticles (NPs) on oxide materials is a commonly employed technique for enhancing the sensitivity and selectivity of materials for gas sensing applications. In this study, we functionalized electrospinning-synthesized SnO2 nanofibers (NFs) with various amounts of Pt NPs to enhance the toluene-sensing properties. In particular, Pt NPs were prepared by deposition of Pt films by sputtering and subsequent heat treatment. Electronic and chemical sensitizations by the Pt NPs were responsible for the improved toluene sensitivity. The best sensing properties were achieved at an optimized amount of Pt NPs, showing a volcano shape in relation to the amount of Pt NPs. The method used in this study is useful for the development of toluene-sensitive and -selective chemiresistive NF-based gas sensors.

N-Heterocyclic Carbene Ligands for Au Nanocrystal Stabilization and Three-Dimensional Self-Assembly

N-Heterocyclic carbenes (NHCs) have emerged as a new class of ligands for materials chemistry that appears particularly relevant for the stabilization and functionalization of metal nanoparticles (NPs). The particular properties and high synthetic flexibility of NHCs make them highly attractive tools for the development of new (nano)materials and the fundamental study of their properties. The relationships between the NHC structure and NP structure/properties, including physical, biological, and self-assembly properties, remain largely unknown. In the past decade, many efforts have been made to gain more fundamental understanding in this area. In this feature article, we present our contribution in this field focusing on the formation of NHC-coated Au nanocrystals (NCs), their stability, and their ability to self-assemble into 3D crystalline structures called supracrystals. First, the formation of NHC-stabilized Au NCs is discussed by comparing different NHC structures, NHC-based Au precursors, and synthesis methods. This study shows the major role of the NHC structure in obtaining both stable NHC-coated Au NCs and narrow size distributions. In a second part, a comparative study of the oxygen resistance of NHC- and thiol-coated NCs is presented, demonstrating the enhanced stability of NHC-coated Au NCs to oxygen-based treatments. Finally, the self-assembly of NHC-coated Au NCs into 3D Au superlattices is presented. The formation of large organized domains of several micrometers is described from the design of NHCs tailored with long alkyl chains. In these different contexts, efforts have been made to gain a more in-depth understanding of the behavior of NHC ligands at the surface of NCs. These results show that the NHC-based approach to nanomaterials has many assets for opening a new research area in the supracrystal world.

Optimization of metal nanoparticle amount on SnO2 nanowires to achieve superior gas sensing properties

SnO2 nanowires (NWs) functionalized with Ag nanoparticles (NPs) were tested for NO2 gas sensing ability; the results revealed a bell-shaped curve as a function of the surface coverage of Ag NPs. A model that can explain these experimental observations regarding the functionalization of metal NPs on oxide NWs, which is the most widely used approach for improving the sensing capabilities of NWs, was proposed and validated. Based on the electronic and chemical sensitizations of metal NPs, a mathematical equation was formulated to predict the optimal surface coverage of metal NPs on the NWs to obtain maximum sensing performance. This study may provide new insight and guidelines for the development of highly sensitive NW-based gas sensors.

Ruthenium dye functionalized gold nanoparticles and their spectral responses

The functionalization of metal nanoparticles provides access to materials with unique chemical and physical properties for a wide range of applications, e.g. in catalysis, optoelectronics and material science. However, the fundamental light induced charge transfer processes and electronic interactions at the functional nanoparticle–molecule interface, which constitute these unique properties, are not yet fully understood. In this work monodisperse spherical gold nanoparticles functionalized by the photoactive ruthenium dyes (Bu4N)2[Ru(dcbpyH)2(NCS)2], (Bu4N)3[Ru(tcterpy)(NCS)3] and [Ru(dnbpy)(dcbpyH2)(NCS)2] (Bu4N = tetrabutylammonium, dcbpyH = 2,2′-bipyridyl-4,4′-dicarboxylato, NCS = isothiocyanato, tcterpy = 2,2′:6′,6′′-terpyridyl-4,4′,4′′-tricarboxylato, dnbpy = 2,2′-bipyridyl-4,4′-dinonyl) known as N719, N749 and Z907, and [Ru(tbbpy)2(tpphz)](PF6)2 (tbbpy = 4,4′-butyl-2,2′-bipyridine, tpphz = tetrapyridophenazine, PF6 = hexafluorophosphate) (Ru) were synthesized in aqueous solution applying a conjugation and a phase transfer reaction approach, respectively. The functionalized nanoparticles obtained were analyzed by UV-vis spectroscopy, TEM imaging and Raman spectroscopic techniques in order to investigate the molecular structures of the photoactive ruthenium dyes at the gold surface. The results indicate, that the dyes' fully conjugated electronic structure and therefore, their photophysical properties, are preserved or only slightly altered upon binding to the surface of the gold nanoparticles, which potentially allows for rapid and efficient transport of charges to the nanoparticles after photoexcitation.

CdSe quantum dot-sensitized Au/TiO2 hybrid mesoporous films and their enhanced photoelectrochemical performance

Novel CdSe quantum dot (QD)-sensitized Au/TiO2 hybrid mesoporous films have been designed, fabricated, and evaluated for photoelectrochemical (PEC) applications. The Au/TiO2 hybrid structures were made by assembly of Au and TiO2 nanoparticles (NPs). A chemical bath deposition method was applied to deposit CdSe QDs on TiO2 NP films with and without Au NPs embedded. We observed significant enhancements in photocurrent for the film with Au NPs, in the entire spectral region we studied (350–600 nm). Incident-photon-to-current efficiency (IPCE) data revealed an average enhancement of 50%, and the enhancement was more significant at short wavelength. This substantially improved PEC performance is tentatively attributed to the increased light absorption of CdSe QDs due to light scattering by Au NPs. Interestingly, without QD sensitization, the Au NPs quenched the photocurrent of TiO2 films, due to the dominance of electron trapping over light scattering by Au NPs. The results suggest that metal NPs are potentially useful for improving the photoresponse in PEC cells and possibly in other devices such as solar cells based on QD-sensitized metal oxide nanostructured films. This work demonstrates that metal NPs can serve as light scattering centers, besides functioning as photo-sensitizers and electron traps. The function of metal NPs in a particular nanocomposite film is strongly dependent on their structure and morphology.

Aminopyrazole-Based Ligand Induces Gold Nanoparticle Formation and Remains Available for Heavy Metal Ions Sensing. A Simple “Mix and Detect” Approach

A novel way to synthesize gold nanoparticles based on the use of N-alkylaminopyrazole is shown. This ligand has a triple functionality: induces AuNPs formation, stabilizes the formed nanoparticles, and even remains available for an external coordination with heavy metal ions. The availability of N-alkylaminopyrazole ligands onto the AuNPs surface is studied using UV-vis and NMR techniques. The mechanism of formation of AuNPs along with the synthesis optimization and characterization are studied using voltammetry and UV-vis, and the results are discussed in detail. The application of N-alkylaminopyrazole-derived gold nanoparticles in the heavy metal ions sensing is also tested showing a high sensitivity for mercury detection at low concentration level. The functionalization of metal nanoparticles with these receptors followed by heavy metal ions detection represents a simple "mix and detect" approach with interest for several other sensing applications.

The effect of adsorption on the conductivity of self-organized metal-poly(para-xylene) nanocomposites

The effect of adsorbed electron donor (ammonia, alcohols, water) and electron acceptor (molecular hydrogen, dichlorobutene, chloroform) molecules on the conductivity of polymeric nanocomposites, representing poly(p-xylene) containing metal (lead, copper, or palladium) nanoparticles (∼10 nm in size), was studied as dependent on the metal content and the gas or vapor pressure at room temperature. It was found that the conductivity significantly (up to eight orders of magnitude) increases due to the adsorption of electron donor molecules and decreases upon the adsorption of electron acceptors. A mechanism of the sensor response is proposed according to which the adsorption simultaneously changes the fractal characteristics of the nanocomposites and the electron work function of metal nanoparticles.