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Magnetically stirrable photocatalysts binding the ZnS-decorated Ni foam with the metal complex cocatalyst as a redox mediator and light-absorbing composition were investigated. Loading metal complex can improve light absorption, surface hydrophilicity, interfacial charge migration, and H 2 production activity. The variation of the metal valences of the composite photocatalysts in an operando environment (with sacrificial agent solution) with and without light irradiation was investigated by X-ray absorption near-edge structure (XANES) spectra and Fourier-transformed extended X-ray absorption fine structure (EXAFS) spectra to monitor the charge carrier dynamics of photocatalysis and explain how the macrocyclic Cu complex (CuC) acted as a redox mediator better than the Ni complex. The smaller valence difference of copper valence in ZS/CuC for dark and light states revealed that the Cu complex facilitates a reversible electron transfer between the ZnS photocatalyst and H + . Loading the Cu complex can improve the separation of photogenerated carriers by the redox couple of complexes, leading to a significantly improved photocatalytic H 2 production activity of 8150 μmol h -1 g -1 . The reactants can flow through these magnetically stirrable Ni foam-based photocatalysts by magnetic-field-driven stirring, which improves the contact between photocatalysts and the sacrificial agents. The operando synchrotron provides new insights for understanding the roles of redox mediators.

Photodynamic therapy (PDT) is a noninvasive medical technology that has been applied in cancer treatment where it is accessible by direct or endoscope-assisted light irradiation. To lower phototoxicity and increase tissue penetration depth of light, great effort has been focused on developing new sensitizers that can utilize red or near-infrared (NIR) light for the past decades. Lanthanide-doped upconversion nanoparticles (UCNPs) have a unique property to transduce NIR excitation light to UV-vis emission efficiently. This property allows some low-cost, low-toxicity, commercially available visible light sensitizers, which originally are not suitable for deep tissue PDT, to be activated by NIR light and have been reported extensively in the past few years. However, some issues still remain in the UCNP-assisted PDT platform such as colloidal stability, photosensitizer loading efficiency, and accessibility for targeting ligand installation, despite some advances in this direction. In this study, we designed a facile phospholipid-coated UCNP method to generate a highly colloidally stable nanoplatform that can effectively load a series of visible light sensitizers in the lipid layers. The loading stability and singlet oxygen generation efficiency of this sensitizer-loaded lipid-coated UCNP platform were investigated. We also have demonstrated the enhanced cellular uptake efficiency and tumor cell selectivity of this lipid-coated UCNP platform by changing the lipid dopant. On the basis of the evidence of our results, the lipid-complexed UCNP nanoparticles could serve as an effective photosensitizer carrier for NIR light-mediated PDT.

An efficient method for modifying the surface of detonation nanodiamonds (5 and 100 nm) with thiol groups (-SH) by using an organic chemistry strategy is presented herein. Thiolated nanodiamonds were characterized by spectroscopic techniques, and the atomic percentage of sulfur was analyzed by elemental analysis and X-ray photoelectron spectroscopy. The conjugation between thiolated nanodiamonds and gold nanoparticles was elucidated by transmission electron microscopy and UV-vis spectrometry. Moreover, the material did not show significant cytotoxicity to the human lung carcinoma cell line and may prospectively be applied in bioconjugated technology. The new method that we elucidated may significantly improve the approach to surface modification of detonation nanodiamonds and build up a new platform for the application of nanodiamonds.

A cadmium-free CuInS2 quantum dot (QD)-sensitized solar cell (QDSC) has been fabricated by taking advantage of the ex situ synthesis approach for fabricating highly crystalline QDs and the in situ successive ionic-layer adsorption and reaction (SILAR) approach for achieving high surface coverage of QDs. The ex situ synthesized CuInS2 QDs can be rendered water soluble through a simple and rapid two-step method under the assistance of ultrasonication. This approach allows a stepwise ligand change from the insertion of a foreign ligand to ligand replacement, which preserves the long-term stability of colloidal solutions for more than 1 month. Furthermore, the resulting QDs can be utilized as sensitizers in QDSCs, and such a QDSC can deliver a power conversion efficiency (PCE) of 0.64%. Using the SILAR process, in situ CuInS2 QDs could be preferentially grown epitaxially on the pre-existing seeds of ex situ synthesized CuInS2 QDs. The results indicated that the CuInS2 QDSC fabricated by the combined ex situ/in situ growth process exhibited a PCE of 1.84% (short-circuit current density = 7.72 mA cm(-2), open-circuit voltage = 570 mV, and fill factor = 41.8%), which is higher than the PCEs of CuInS2 QDSCs fabricated by ex situ and in situ growth processes, respectively. The relative efficiencies of electrons injected by the combined ex situ/in situ growth approach were higher than those of ex situ synthesized CuInS2 QDs deposited on TiO2 films, as determined by emission-decay kinetic measurements. The incident photon-to-current conversion efficiency has been determined, and electrochemical impedance spectroscopy has been carried out to investigate the photovoltaic behavior and charge-transfer resistance of the QDSCs. The results suggest that the combined synergetic effects of in situ and ex situ CuInS2 QD growth facilitate more electron injection from the QD sensitizers into TiO2.

A new magnetic resonance/optical nanoprobe with specific cellular targeting capabilities based on nontoxic CuInS2/ZnS quantum dots (QDs) with direct covalent attachment of a Gd(III)-complex for tumor-specific imaging is reported. We introduce amphiphilic poly(maleic anhydride-alt-1-octadecene) to interdigitate with hydrophobic, protective agents on the surface of CuInS2/ZnS QDs that allows phase transfer of hydrophobic QDs from the organic into aqueous phase. Carbodiimide chemistry is used to covalently couple the Gd(III) complex on the surface of CuInS2/ZnS QDs, and then folic acid is further utilized to functionalize this dual-modality nanoprobe for active tumor targeting based on the fact that the membrane-associated folate receptor is overexpressed in many tumor cells. The longitudinal relaxivity value is 3.72 mM(-1) s(-1) for the dual-modality nanoprobe and a clear, positive, and increasing contrast enhancement of magnetic resonance signals concurrently with increasing Gd(III) concentration is observed. The dual-modality nanoprobe exhibits negligible cytotoxicity with >80% cell viability at a concentration of up to 100 μg/mL in human cervical (HeLa), human liver carcinoma (HepG2), and human breast (MCF-7) cells after 24 h. The specificity of folic-acid-conjugated nanoprobe cellular uptake has been investigated by confocal scanning laser imaging, which revealed that HeLa cells, expressing the folate receptor, internalized a higher level of dual-modality nanoprobes than HepG2 and MCF-7 cells.

In this study we used atom transfer radical polymerization to graft poly(N-isopropylacrylamide) (PNIPAAm) onto flat Si substrates. We then applied very large-scale integration and reactive ion etching sequentially to generate 200-nm-scale hole arrays of tethered PNIPAAm as two-dimensional periodic concave gratings (2DPCGs) on the Si surfaces. The hole array structures of tethered PNIPAAm could be created and erased reversibly at 25 and 40 °C, respectively, leading to significant changes in the effective refractive index (neff). The values of neff of the 2DPCGs were related to the depth of their holes generated after etching for various times, resulting in a color change from blue to red that could be observed by the naked eye at incident angles of 10-20°. Moreover, we used effective-medium theory to calculate the filling factors of air inside the 2DPCGs to verify the structural changes of the tethered PNIPAAm. Such designed 2DPCGs of thermorespective hydrogel films have potential applications in temperature-responsive optical devices [e.g., as antireflection structured surfaces (ARSs)] that operate at both visible and near-infrared wavelengths.

In this study, we fabricated a nanopillar array of silicon oxide, involving very-large-scale integration (VLSI) and reactive ion etching (RIE), as two-dimensional periodic relief gratings (2DPRGs) on Si surfaces. Antihuman ALB was successively oriented on the pillar surface of 2DPRG modified protein G as an optical detector that is specific for targeted antigen. The antibody modified 2DPRG alone produces insignificant structure change, but upon immunocapture of antigens, the antigen filling in the 2DPRG leads to a dramatic change of the pillar scale. Binding of the antibodies to the 2DPRG occurs in a way that still allows them to function and selectively bind antigen. The performance of the sensor was evaluated by capturing HRP-human ALB on the antibody-modified 2DPRG and measuring the effective refractive index (neff) resulting from the attachment of antigens. The neff values of the 2DPRG are found to relate with the pillar scale of the 2DPRG, generated by antigen coupling, resulting in color change from pure green to orange, observed by the naked eye along an incident angle of 10-20°. Moreover, we calculated the filling factors inside the 2DPRG with effective-medium theory to verify the pillar structure changes. This technique eliminates much of the surface modifications and the secondary immunochemical or enzyme-linked steps that are common in immunoassays. Such films have potential applications as optical biosensors.

In this study, we synthesized core/shell structures comprising monodisperse 3-μm SiO(2) microspheres and gold nanoparticles (AuNPs, ca. 6.7 nm) as the core and shell components, respectively. Using a layer-by-layer cross-linking process with a dithiol cross-linking agent, we prepared low-permittivity AuNP-encapsulated high-permittivity SiO(2) core/shell microspheres with variable AuNP shell thicknesses. The dispersivity of the microspheres in solution was enhanced after grafting poly(ethylene glycol) monomethyl ether thiol (PEG-SH) onto the AuNP layer on the SiO(2) microspheres. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images revealed sesame ball-like structures for these SiO(2)@AuNP@PEG microspheres. We encapsulated aqueous dispersions of these SiO(2)@AuNP microspheres into sandwich structured displays (SSDs) to investigate their electrorheological properties, observing reversibly electroresponsive transmittance that is ideally suited for display applications. Increasing the thickness of the AuNP layer dramatically enhanced the stringing behavior of the SiO(2) microspheres, resulting in increased transmittance of the SSD. The response time of the electroresponsive electrorheological fluids also decreased significantly after modifying the SiO(2) with the AuNP layers. The effective permittivities of these composites could be predicted from the real (έ) and imaginary (έ́) parts of the Clausius-Mossotti formalism.

In this work, we focus on the fabrication of the nanoassemblies consisting of the poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) brushes and gold nanoparticles (AuNPs). The employed process involves grafting of the PDMAEMA chains on an underlying substrate in a brush conformation followed by the immobilization of surface functionalized AuNPs by means of physical interaction (electrostatic attraction, entanglement, and hydrogen bonding). Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy have been employed to characterize the prepared PDMAEMA-AuNP nanoassemblies. Polymer brushes possessing various thicknesses have been found to suppress the nanoparticles' aggregation and, hence, facilitate the surface coverage. Furthermore, we patterned the PDMAEMA-AuNP nanoassemblies as an one-dimensional periodic relief grating (OPRG). The subwavelength structure of OPRG has the optical features including artificial refractive index, form birefringence and resonance and band gap effects. A mean refractive index of the PDMAEMA-AuNP nanoassemblies can be controlled by the filling factors of the OPRG structure, so that a desired distribution of refractive index of the polymer brushes-gold OPRG under various stimuli can be realized. The employed approach is simple and highly versatile for the modification of surfaces with a wide range of NPs.

We have used a very large scale integration process to generate well-defined patterns of polymerized 2-hydroxyethyl methacrylate (HEMA) on patterned Si(100) surfaces. An atom transfer radical polymerization initiator covalently bonded to the patterned surface was employed for the graft polymerization of HEMA to prepare the poly(2-hydroxyethyl methacrylate) (PHEMA) brushes. After immersing wafers presenting lines of these polymers in water and cyclohexane, we observed brush- and mushroom-like regions, respectively, for the PHEMA brushes, with various pattern resolutions. The PHEMA brushes behaved as "tentacles" that captured ferritin complexes from aqueous solution through entanglement between the brushes and the ferritin proteins, whose ferritins were trapped due to the collapsing of the PHEMA. Using high-resolution scanning electron microscopy, we observed patterned ferritin iron cores on the Si surface after thermal removal of the patterned PHEMA brushes and ferritin protein sheaths.