composition and optical properties of copper nanoparticles ..
Li . designed folate receptor-targeted hollow gold nanospheres carrying siRNA recognizing NF-B, a transcription factor related to the expression of genes involved in tumor development [,]. In this case, the photothermal effects of gold nanospheres were utilized to regulate drug release and as a therapeutic tool. Core/shell-structured hollow gold nanospheres (HAuNS, 40 nm) were initially synthesized, consisting of a thin gold wall with a hollow interior, and the structures displayed strong surface plasmon resonance (SPR) tunability in the near-IR region [-]. Thiol-modified siRNA duplexes directed toward the NF-B p65 subunit were then introduced to the surface of HAuNS. Folates were coupled to the nanoparticles through a thioctic acid-terminated PEG linker to produce F-PEG-HAuNS-siRNA (Figure A and B). Irradiation with a pulsed near-IR laser (800 nm) altered the absorption spectra of the HAuNS-siRNA solutions significantly, indicating a loss in the structural integrity and triggering the dissociation of siRNA from HAuNS, when demonstrated by TEM and fluorescence microscopy images. This mode of action is termed 'photothermal transfection'. Intravenous injection of the nanospheres into HeLa xenografts resulted in the distinct downregulation of the NF-B p65 subunit only for the folate-conjugated nanosphere treatment combined with near-IR laser irradiation, suggesting that selective targeting and endolysosomal escape of the nanoparticles was activated by near-IR irradiation at the tumor site. tests, in which therapy was combined with administration of irinotecan, a chemotherapeutic agent that increases sensitivity to NF-B inhibition, yielded a substantially enhanced apoptotic response (Figure C). micro-positron emission tomography (PET))/computed tomography (CT) imaging also confirmed the folate-mediated tumor-targeted theranostic properties of the nanostructures (Figure D). Although significant uptake of the nanoparticles was observed in the liver, spleen, kidney, and lung, no significant downregulation of p65 in these organs was observed as a result of the tumor-selective near-IR irradiation.
Synthesis and optical properties of Bi3+ doped NaTaO3 …
The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications in catalysis. The synthesis part discusses numerous preparative protocols for Cu and Cu-based nanoparticles, whereas the application sections describe their utility as catalysts, including electrocatalysis, photocatalysis, and gas-phase catalysis. We believe this critical appraisal will provide necessary background information to further advance the applications of Cu-based nanostructured materials in catalysis.
Riboflavin is an essential vitamin for cellular metabolism, and the riboflavin carrier protein (RCP) is highly upregulated in metabolically active cells [,]. Thus, flavin mononucleotide (FMN), an endogenous RCP ligand, was used as a small molecule targeting ligand for metabolically active cancer or endothelial cells. Kiessling and co-workers synthesized FMN-coated ultrasmall superparamagnetic iron oxide nanoparticles (FLUSPIO) as MRI/optical dual probes for cancer detection . USPIO was coated with FMN through the phosphate groups of FMN, and guanosine monophosphate was added to stabilize the colloid. The hydrodynamic radius of FLUSPIO was 97 ± 3 nm, and an intense fluorescence emission band was observed at 530 nm due to FMN. cellular uptake of FLUSPIO was investigated by MRI (3T), TEM, and fluorescence microscopy of PC3 cells and HUVEC cells. Both PC3 cells and HUVEC cells showed a significantly higher R2 relaxation rate after 1 h incubation with FLUSPIO than with nontargeted USPIO. Such an uptake was considerably reduced by competitive blocking of RCP with free FMN. A strong green fluorescence in the cells was observed after FLUSPIO incubation. The perinuclear fluorescence signal suggested endosomal localization of the nanoparticles, consistent with TEM results, suggesting that FMN could serve as a versatile building block for generating tumor-targeted imaging and therapeutic modalities.
Nanocomposites: synthesis, structure, properties and …
The increasing interest in nanoparticles (NPs) due to their unique properties and
multifarious applications has necessitated the development of new analytical tools for characterizing NPs in a fast and reproducible manner. Especially, to better understand the fundamental properties, correlate structure-function relationships of NPs and optimize NPs activity for various applications analytical tools that enable precise characterization of individual NPs in terms of their size, shape and composition are of immense importance. The development of “electrocatalytic amplification” is one such method where single NPs are detected by measuring electrocatalytic current due to the electrochemical processes (oxidation/reduction of the species present in solution) occurring on the surface of the NP whenever a NP collides with an inert UME (gold, platinum, platinum oxide and carbon) which otherwise cannot catalyze the reaction.
Journal of Nanoscience and Nanotechnology
Stable linkages between nanoparticles and functional moieties may be provided by iodoacetate linkers. Using this linker, Zhang synthesized a CTX-mediated brain tumor targeting magnetic/optical nanoprobe . As shown in Figure , amine-functionalized nanoparticles were prepared by synthesizing a PEG-grafted chitosan polymer. Methoxy-PEG was oxidized to yield PEG-aldehyde, which was then reacted with the primary amines of depolymerized chitosan by formation of a Schiff base. Subsequently, iron oxide nanoparticles were coated with a PEGylated chitosan-branched copolymer (NPCP). SATA-pretreated CTX was then conjugated to the nanoparticles via an SIA cross-linker. The nanoparticles were linked to fluorescence imaging dyes by conjugating the amine groups remaining on the iron oxide nanoparticles to a Cy5.5 NHS ester, producing NPCP-Cy5.5-CTX as a brain tumor targeting magnetic/optical nanoprobe.