Nano-bio effects: interaction of nanomaterials with cells.

With the advancements in nanotechnology, studies on the synthesis, modification, application, and toxicology evaluation of nanomaterials are gaining increased attention. In particular, the applications of nanomaterials in biological systems are attracting considerable interest because of their unique, tunable, and versatile physicochemical properties. Artificially engineered nanomaterials can be well controlled for appropriate usage, and the tuned physicochemical properties directly influence the interactions between nanomaterials and cells. This review summarizes recently synthesized major nanomaterials that have potential biomedical applications. Focus is given on the interactions, including cellular uptake, intracellular trafficking, and toxic response, while changing the physicochemical properties of versatile materials. The importance of physicochemical properties such as the size, shape, and surface modifications of the nanomaterials in their biological effects is also highlighted in detail. The challenges of recent studies and future prospects are presented as well. This review benefits relatively new researchers in this area and gives them a systematic overview of nano-bio interaction, hopefully for further experimental design.

Targeting polymeric fluorescent nanodiamond-gold/silver multi-functional nanoparticles as a light-transforming hyperthermia reagent for cancer cells.

This work demonstrates a simple route for synthesizing multi-functional fluorescent nanodiamond-gold/silver nanoparticles. The fluorescent nanodiamond is formed by the surface passivation of poly(ethylene glycol) bis(3-aminopropyl) terminated. Urchin-like gold/silver nanoparticles can be obtained via one-pot synthesis, and combined with each other via further thiolation of nanodiamond. The morphology of the nanodiamond-gold/silver nanoparticles thus formed was identified herein by high-resolution transmission electron microscopy, and clarified using diffraction patterns. Fourier transform infrared spectroscopy clearly revealed the surface functionalization of the nanoparticles. The fluorescence of the materials with high photo stability was examined by high power laser irradiation and long-term storage at room temperature. To develop the bio-recognition of fluorescent nanodiamond-gold/silver nanoparticles, pre-modified transferrin was conjugated with the gold/silver nanoparticles, and the specificity and activity were confirmed in vitro using human hepatoma cell line (J5). The cellular uptake analysis that was conducted using flow cytometry and inductively coupled plasma mass spectrometry exhibited that twice as many transferrin-modified nanoparticles as bare nanoparticles were engulfed, revealing the targeting and ease of internalization of the human hepatoma cell. Additionally, the in situ monitoring of photothermal therapeutic behavior reveals that the nanodiamond-gold/silver nanoparticles conjugated with transferrin was more therapeutic than the bare nanodiamond-gold/silver materials, even when exposed to a less energetic laser source. Ultimately, this multi-functional material has great potential for application in simple synthesis. It is non-cytotoxic, supports long-term tracing and can be used in highly efficient photothermal therapy against cancer cells.

Plasmonic ZnO/Ag embedded structures as collecting layers for photogenerating electrons in solar hydrogen generation photoelectrodes.

A new fabrication strategy in which Ag plasmonics are embedded in the interface between ZnO nanorods and a conducting substrate is experimentally demonstrated using a femtosecond-laser (fs-laser)-induced plasmonic ZnO/Ag photoelectrodes. This fs-laser fabrication technique can be applied to generate patternable plasmonic nanostructures for improving their effectiveness in hydrogen generation. Plasmonic ZnO/Ag nanostructure photoelectrodes show an increase in the photocurrent of a ZnO nanorod photoelectrodes by higher than 85% at 0.5 V. Both localized surface plasmon resonance in metal nanoparticles and plasmon polaritons propagating at the metal/semiconductor interface are available for improving the capture of sunlight and collecting charge carriers. Furthermore, in-situ X-ray absorption spectroscopy is performed to monitor the plasmonic-generating electromagnetic field upon the interface between ZnO/Ag nanostructures. This can reveal induced vacancies on the conduction band of ZnO, which allow effective separation of charge carriers and improves the efficiency of hydrogen generation. Plasmon-induced effects enhance the photoresponse simultaneously, by improving optical absorbance and facilitating the separation of charge carriers.

Plasmon inducing effects for enhanced photoelectrochemical water splitting: X-ray absorption approach to electronic structures.

Artificial photosynthesis using semiconductors has been investigated for more than three decades for the purpose of transferring solar energy into chemical fuels. Numerous studies have revealed that the introduction of plasmonic materials into photochemical reaction can substantially enhance the photo response to the solar splitting of water. Until recently, few systematic studies have provided clear evidence concerning how plasmon excitation and which factor dominates the solar splitting of water in photovoltaic devices. This work demonstrates the effects of plasmons upon an Au nanostructure-ZnO nanorods array as a photoanode. Several strategies have been successfully adopted to reveal the mutually independent contributions of various plasmonic effects under solar irradiation. These have clarified that the coupling of hot electrons that are formed by plasmons and the electromagnetic field can effectively increase the probability of a photochemical reaction in the splitting of water. These findings support a new approach to investigating localized plasmon-induced effects and charge separation in photoelectrochemical processes, and solar water splitting was used herein as platform to explore mechanisms of enhancement of surface plasmon resonance.

Nickel complexes incorporating an amido phosphine chelate with a pendant amine arm: synthesis, structure, and catalytic Kumada coupling.

A series of organonickel(II) complexes incorporating an amido phosphine ligand tethered with an amino pendant have been prepared and characterized. Deprotonation of N-(dimethylaminoethyl)-2-diphenylphosphinoaniline (H[PNN]) with one equivalent of n-BuLi in ethereal or hydrocarbon solutions at -35 °C generates cleanly dimeric {Li[PNN]}(2) as yellow crystals. The reaction of NiCl(2)(DME) with {Li[PNN]}(2) in THF at -35 °C affords green crystalline [PNN]NiCl. Treating [PNN]NiCl with NaX in acetone solutions gives [PNN]NiX (X = Br, I). Alkylation or arylation of [PNN]NiCl with appropriate Grignard reagents in THF at -35 °C produces red crystalline [PNN]NiR (R = Me, Et, i-Bu, n-hexyl, CH(2)Ph, Ph). The chloride complex [PNN]NiCl was found to be an active catalyst precursor for Kumada coupling reactions of PhX (X = I, Br, Cl) with aryl or alkyl Grignard reagents, including those containing ß-hydrogen atoms. The X-ray structures of {Li[PNN]}(2) and [PNN]NiX (X = Cl, Br, Me, Et, n-hexyl) are reported.

Aluminium complexes of bidentate N,O- and N,N-ligands derived from oxidative functionalization of amido phosphines: synthesis, structure and reactivity.

A series of amido phosphinoxide and amido phosphinimine ligands that are electronic variations of monoanionic N,O- and N,N-ketiminates have been prepared and employed to examine the coordination chemistry of aluminium. Oxidation of the previously established N-(2-diphenylphosphinophenyl)-2,6-dialkylaniline in the presence of H(2)O(2) or organic azides RN(3) (R = 2,6-C(6)H(3)(i)Pr(2), SiMe(3)) led to phosphinoxides (H[NO] 1a-b) and phosphinimines (H[NN] 1c-d), respectively. Alkane elimination reactions of these protio-ligand precursors with trialkylaluminium in toluene or pentane solutions afforded cleanly the corresponding organoaluminium complexes, including dimethyl 2a-d, diethyl 3a-d and diisobutyl derivatives 4a-b and 4d. Solution NMR studies revealed Cs symmetry for these organoaluminium species, in which the α-hydrogen atoms are all diastereotopic. The correlation between the steric congestion of these molecules and the degree of resolution of the multiplet signals corresponding to the diastereotopic α-hydrogen atoms observed by the (1)H NMR spectroscopy is of particular interest. Dichloroaluminium complexes 5c-d were prepared in high yields by protonolysis of MeAlCl(2) with 1c-d. Single-crystal X-ray diffraction analyses of 2c-d, 3a, 3d, 4a, and 4d elucidated a mononuclear, distorted tetrahedral core for all of these aluminium species. Interestingly, complexes 2c-d are active initiators for catalytic ring-opening oligomerization of ε-caprolactone, whereas 2a-b are rather inactive, highlighting the significance of the steric hindrance imposed by the amido phosphinimine ligands, as compared to that imposed by the phosphinoxide counterparts.

Biphenolate phosphine complexes of tantalum.

The preparation and structural characterization of tantalum complexes supported by 2,2'-phenylphosphino-bis(4,6-di-tert-butylphenolate) ([OPO](2-)) are described. The reaction of Li(2)[OPO] with TaCl(5), regardless of the molar ratio employed, in diethyl ether at -35 degrees C led to high-yield isolation of yellow crystalline [OPO](2)TaCl. Alkylation of [OPO](2)TaCl with MeMgBr or EtMgCl in diethyl ether at -35 degrees C generated the corresponding alkyl complexes [OPO](2)TaR (R = Me, Et). Thermolysis of [OPO](2)TaEt in benzene led to quantitative formation of [OPO](2)TaH, which could also be prepared by treatment of [OPO](2)TaCl with LiHBEt(3) in diethyl ether at -35 degrees C. Hydrolysis of [OPO](2)TaCl or [OPO](2)TaR (R = H, Me, Et) generated [OPO](2)TaOH. The reaction of [OPO](2)TaOH with Me(3)SiCl in diethyl ether at room temperature afforded quantitatively [OPO](2)TaCl. The solution structures of these complexes were all characterized by multinuclear NMR spectroscopy. The solid-state structures of [OPO](2)TaCl, [OPO](2)TaH, and [OPO](2)TaOH were determined by X-ray crystallography. The spectroscopic and crystallographic data are all indicative of the coordination of both phosphorus donors to tantalum in these 7-coordinate complexes. Interestingly, the structure of [OPO](2)TaH is markedly different from those of [OPO](2)TaX (X = Cl, OH, Me, Et) on the basis of NMR and X-ray studies. Density functional theory computations reveal that the hydride structure found by X-ray crystallography is lower in energy by about 7 kcal/mol than that analogous to the established X-ray structures of [OPO](2)TaCl and [OPO](2)TaOH.