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In order for the colloidal crystal films to be better applied, the influence of relative humidity on the preparation of silica colloidal crystal (SCC) films was systematically studied to solve the problem of different thicknesses of SCC films prepared by different batches under the conditions with the same temperature, concentration of suspension and diameter of the particles. SCC films with 190 nm particles were prepared by static vertical deposition method under different humidity regulated by saturated salt solutions, and the thickness of the films was obtained by an interferometric method. The results showed that the increase in humidity would reduce the thickness of the prepared films, which was believed to be caused by the decrease in evaporation rate after the wetting film absorbs water vapor. A new formula for calculating film thickness was proposed and verified from a series of experiments. With the control of humidity, high-quality SCC films with controlled thickness can be repeatedly prepared.

This work presents the synthesis and characterization of Au nanostars (AuNSs) and demonstrates their application as surface enhanced Raman scattering (SERS)-activity tags for cellular imaging and sensing. Nile blue A (NBA) and bovine serum albumin (BSA) were used as Raman reporter molecules and capping materials, respectively. The SERS-activity tags were tested on human lung adenocarcinoma cell (A549) and alveolar type II cell (AT II) and found to present a low level of cytotoxicity and high chemical stability. These SERS-activity tags not only can be applied in multiplexed cellular imaging, including dark field imaging, transmission electron microscopy (TEM) and SERS imaging, but also can be used for cellular sensing. The SERS spectra clearly identified cellular important components such as proteins, nucleic acids, lipids, and carbohydrates. This study also shows that endocytosis is the main channel of tags internalized in cells. The AuNSs exhibiting strong surface enhanced Raman effects are utilized in the design of an efficient, stable SERS-activity tag for intracellular applications.

To constructing effective hotspot arrays in SERS substrates, gold nanoshells (GNSs) were assembled layer by layer on acupuncture needles by covalent absorption of bifunctional chemicals; three dimensional structures of the GNSs were locked by polystyrene (PS) coating; effective hotspots were obtained by removing bifunctional chemicals on surface of the GNSs, and the spacing between GNSs was enlarged by corroding gold shell layers of the GNSs partly. The strongest SERS signal was obtained from the SERS-active substrate with two-layer GNSs. After effective hotspot arrays were constructed in the SERS-active substrate with two-layer GNSs, its enhancement factor was higher about two to three orders of magnitude than that of the monolayer of close-packed GNSs. The hotspot arrays integrated on acupuncture needles would be used to detect low concentration of biomolecules in vivo.

Novel core-shell structures were presented here which consist of Poly(N-isopropyl acrylamide) (PNIPAM) microspheres as cores and gold as shells. The fabrication of these structures was convenient because the modifications to PNIPAM or gold nanoparticles (GNPs) were omitted. GNPs were attached to the surface of PNIPAM microspheres by means of electrostatic adsorption, and then acted as seeds to grow quickly into complete shells by optimizing the pH of the HAuCl4 solution to control the growth rate of gold nanoshells (GNSs). These structures combine the thermo-responsive behavior of PNIPAM microspheres with optical property of GNSs, and the localized surface plasmon resonance (LSPR) of the GNSs can be changed by adjusting the temperature of the PNIPAM microspheres which make them have great prospects for drug release. Their good biological stability in bovine serum albumin (BSA) and the LSPR located near 700 nm are expected for optical biosensors and optical analysis of whole-blood.

We present here a facile route to in-situsynthesis of free-standing metal (gold or silver) nanoparticles-embedded chitosan films by thermal treatment. The produced nanoparticles were confirmed by UV-vis spectroscopy and transmission electron microscopy (TEM). Interestingly, an exquisite dendritic structure was observed in the resulting silver-chitosan film, which was not present in pure chitosan and gold-chitosan samples. We speculated that the formation of dendritic structures may be due to the presence of nano-sized silver particles which has an influence on the crystallization behavior and thereby the morphology of biopolyer chitosan. The application of the as-prepared metal-chitosan films in surface-enhanced Raman spectroscopy (SERS) was investigated by using Rhodamine 6G (R6G) as probe molecules. It was found that the resultant metal-chitosan samples, especially silver-chitosan one, could be used as SERS substrates exhibiting excellent enhancement ability.

We demonstrate herein a "green" pathway for the formation of a gold nanocomposite using the cuttlebone-derived organic matrix. The gold nanocomposite is achieved through the first exposure of the organic matrix to HAuCl4 solution at room temperature and its subsequent heating at 80 °C. The process results in the formation of a macro porous gold nanocomposite consisting of gold nanoparticles embedded in the cuttlebone-derived organic matrix background, which shows the characteristic plasma absorption of gold nanostructures. UV-vis-IR spectrophotometer and transmission electron microscope (TEM) were used to characterize the gold nanocomposite and trace the formation process. A highlight of the research is that we adopted a nontoxic and renewable reagent of cuttlebone-derived organic matrix, which functioned as the reducing reagent, stabilizer and scaffold for the synthesis of gold nanoparticles.

We demonstrate herein a "green" pathway for the formation of a gold nanocomposite using the cuttlebone-derived organic matrix. The gold nanocomposite is achieved through the first exposure of the organic matrix to HAuCl4 solution at room temperature and its subsequent heating at 80 degrees C. The process results in the formation of a macro porous gold nanocomposite consisting of gold nanoparticles embedded in the cuttlebone-derived organic matrix background, which shows the characteristic plasma absorption of gold nanostructures. UV-vis-IR spectrophotometer and transmission electron microscope (TEM) were used to characterize the gold nanocomposite and trace the formation process. A highlight of the research is that we adopted a nontoxic and renewable reagent of cuttlebone-derived organic matrix, which functioned as the reducing reagent, stabilizer and scaffold for the synthesis of gold nanoparticles.

An interface of gold nanoshells (GNSs) was constructed on the surface of the 3-aminopropyl triethoxysilane (APTES) modified ITO glass substrates by a simple self-assemble method to form the GNSs-coated ITO electrode. UV-vis spectroscopy, scanning electron microscopy (SEM), and cyclic voltammetry were used to characterize the GNSs interface architectures. SEM and UV-vis spectroscopy showed that an interconnected and stable GNSs interface was formed on the APTES modified ITO glass substrate. The cytochrome b562 (Cyt b562) was selected to observe electron transfer reactions of redox protein at the GNSs-coated ITO electrodes. Quasi-reversible electrochemistry of Cyt b562 was obtained and its electrochemical behaviors were discussed.