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High-performance recyclable SERS substrates with well-ordered hybrid nanostructure gold nanoparticles (Au NPs) decorated on titanium dioxide nanorods (TiO2 NRs) were successfully prepared by combining two methods. The TiO2 NRs were fabricated by electron-beam evaporation with glancing-angle deposition (GLAD) technique, then the Au NPs were decorated onto the TiO2 NRs surfaces by deposition-precipitation (DP). The physical structures of the obtained hybrid nanostructures were characterized by field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscope (TEM), and grazing incident angle X-ray diffraction (GIXRD). The results indicated that size and density of Au NPs on TiO2 NRs were controlled by HAuCl4 concentration for optimization of the SERS performance whose the detection of MB molecules was achieved at an enhancement factor of 6.5 × 107 with 9.76%-RSD at 1626 cm−1. More significantly, the optimized hybrid nanostructure SERS substrates exhibit excellent recyclability. These hybrid nanostructure SERS substrates were therefore promising towards detection of TNT for homeland security applications, as well as an on-site SERS platform.

Revision of Detailed experiments

A resonance Rayleigh scattering (RRS) method for determination of Hg2+ concentration using positively charged gold nanorods (GNRs) and thymine-rich single-stranded DNA (ssDNA) was developed. Hg2+ can induce a conformation change of ssDNA from a random coil to a hairpin structure via thymine–Hg2+–thymine coordination. Hairpin shaped DNA possesses a high density of negative charges, therefore it caused in a drastic aggregation of GNRs. This resulted in an enhancement of RRS intensity. In this work, a change in RRS intensity proportional to the concentration of Hg2+ was monitored by spectrofluorometer at excitation and RRS wavelengths of 550 nm (λex = λRRS). This method offered a detection limit of 0.23 nM, which is lower than the maximum mercury contaminant level specified by the US Environmental Protection Agency. Good precision of analysis was obtained (3.1% relative standard deviation). Furthermore, the method was simple, involving in-situ mixing and sensing in a one-pot solution. Detection was accomplished in 5 min. This makes the method advantageous in terms of convenience and rapidity of analysis. The developed method was successfully applied for detection of Hg2+ in tap water samples. Recoveries were found in range of 100.6–119.0%.

Bismuth nanostructures are of interest due to unique properties such as strong diamagnetism, high magnetoresistance under magnetic field, as well as biocompatibility compared with lead. Previous study have reported a relationship of obtained nanostructures and synthesized conditions including pH, temperature and time during nucleation. Most of them confront difficulties on size controlling, particularly in large volume synthesis. Therefore, the goal of this work is to simplify the synthesis method by studying an effect of additive chemicals which are introduced to a growth solution before nanocrystal formation. Ascorbic acid, dioctyl sulfosuccinate sodium salt (AOT) and ethanol were chosen to slow down the reaction or disturb the micellar template. The study has shown that size of nanoparticles can be easily tuned by adding different amount of aforementioned chemicals. According to different role in nanocrystal forming mechanism, more ascorbic acid tends to increase diameter of obtained particles. Oppositely, more AOT has shrunk synthesized particles due to packed micelles. Loose micelles are found in ethanol experiment leading to bigger particles in size. In addition, crystalline structure exhibited the diffraction plane at (012), (104), and (110) with X-Ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FE-SEM) was used to determine morphology of nanoparticles, and also size distribution was confirmed by nanoparticle tracking analysis (NTA). We also found the quench of nanocrystal formation in the presence of high concentration of ethyl alcohol.

The purpose of this research is to obtain a facile method for bismuth nanorod synthesis. Bismuth nitrate pentahydrate [Bi(NO3)3•5H2O] was used as a precursor and rod-like formation was found at 80 °C in the presence of hydrazine hydrate and sodium oleate. We also found here that incubation time plays an important role in shape regulation and the presence of CTAB obstructs rod formation. The nanostructures were characterized by X-Ray diffraction (XRD) for crystalline structures examination. Moreover, field emission scanning electron microscopy (FE-SEM) was performed to determine morphology of nanostructures, whereas size distribution was analyzed using nanoparticle tracking analysis (NTA).

Metal halide-based perovskite materials have received great attention in scintillating applications because they can emit strong visible light when interacting with X-ray particles. Here, we report a scintillator based on rubidium copper chlorine incorporated in the polydimethylsiloxane matrix. The scintillator shows a bright violet emission under ultraviolet and ionizing radiation. The temperature-dependent photoluminescence and radioluminescence shows maximum thermal enhancement at 80°C and 60°C, respectively. Moreover, the first X-ray image from this material reveals the detailed information of the object captured by a commercially available digital camera, indicating a potent scintillator for creating X-ray imaging screens.

In this paper, the electric field distribution in designed liquid lens were simulated and demonstrated. The concentric interdigitate electrode was designed to generate the non-uniform electric field. Consequently, two liquid material on electrode undergoes dielectrophoresis (DEP) phenomenon and forming curvature can confine the incident light. Such two immiscible liquids were studied in the criteria of significant difference in dielectric constant such as Δε≈20. To be specific, the higher dielectric constant liquid as a lens material was first considered comparing to the ambient one. The simulation results reveal that, with fixed electrode width of 25 µm, the increasing gap of electrode from 25 to 125 µm can increase electric field strength at the lens apex from 237 to 386 V/m. Interestingly, the electric field strength was enhanced up to 533 V/m when the electrode width was increased. When the lower dielectric constant liquid was used as lens material, the electric field strength at the fixed width of 25 µm was increased from 16 to 71 V/m as the increasing gap from 25 to 125 µm. However, the low electric field strength of 63 V/m was obtained at broaden width of electrode. In both cases, the electric field strength is not significantly increased at the larger width for all conditions. Our model can be benefit for promising liquid lens design in term of low energy, cost reduction and compact device.

Hybrid nanomaterials exhibit multi-functionalities, which is synergy or enhanced physical and optical properties over their single components with promising potentials for various applications in dye-sensitized solar cell and photocatalytic materials. In this present research, the Au nanoparticles were prepared at HAuCl4 concentration of 0.5 mM on ZnO nanorod templates and silicon wafer substrate by hydrothermal reaction process. The prepared samples were investigated the crystal structure, chemical composition and morphologies by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and field-emission scanning electron microscopy (FESEM), respectively. The XRD results shown that ZnO was preferred orientation along the c-axis (002). The FE-SEM images indicated to the difference of size-Au NPs decorated on ZnO nanorods and silicon wafer. The relationship between the surface area and the size of Au NPs of the prepared samples was investigated and possible growing mechanism of Au NPs on ZnO nanorods templates will be discussed.

Journal of Metals, Materials and Minerals, 28, 2, 69-75

Water-soluble fluorescent CdSe/CdZnS quantum dots (QDs) (λem=637nm) were used as a labelling reporter for strip detection. The CdSe/CdZnS QDs was prepared by using core shell technique where CdSe QDs (λem=590nm) core was capped with CdZnS shell. CdZnS-QDs were conjugated with amine-modified DNA probe, that can bio-recognize with DNA product for use in lateral flow assays (LFAs) detection. The presence of functionalized water-dispersible QDs was confirmed by Fourier transform infra-red (FTIR) technique, where a characteristic carboxylic group was observed at 1633 cm−1 (-OH) and 3310 cm−1 (-COO). DNA probe was immobilized onto QDs by EDC/NHS pathways and confirmed by protein absorption spectra at 260 nm due to heterocyclic ring of nucleosides. QDs-DNA can be applied as labelling reporter to readout fluorescence signal on the LFAs detection.

We present a magnetoplasmonic nanoplatform combining gold nanorods (GNR) and iron-oxide nanoparticles within phospholipid-based polymeric nanomicelles (PGRFe). The gold nanorods exhibit plasmon resonance absorbance at near infrared wavelengths to enable photoacoustic imaging and photothermal therapy, while the Fe 3 O 4 nanoparticles enable magnetophoretic control of the nanoformulation. The fabricated nanoformulation can be directed and concentrated by an external magnetic field, which provides enhancement of a photoacoustic signal. Application of an external field also leads to enhanced uptake of the magnetoplasmonic formulation by cancer cells in vitro. Under laser irradiation at the wavelength of the GNR absorption peak, the PGRFe formulation efficiently generates plasmonic nanobubbles within cancer cells, as visualized by confocal microscopy, causing cell destruction. The combined magnetic and plasmonic functionalities of the nanoplatform enable magnetic field-directed, imaging-guided, enhanced photo-induced cancer therapy. From the Clinical Editor In this study, a nano-formulation of gold nanorods and iron oxide nanoparticles is presented using a phospholipid micelle-based delivery system for magnetic field-directed and imaging-guided photo-induced cancer therapy. The gold nanorods enable photoacoustic imaging and photothermal therapy, while the Fe 3 O 4 nanoparticles enable magnetophoretic control of the formulation. This and similar systems could enable more precise and efficient cancer therapy, hopefully in the near future, after additional testing.

Well-defined tertiary amine-functionalized cationic polylactides (CPLAs) are synthesized by thiol-ene click functionalization of an allyl-functionalized polylactide, and utilized here for the delivery of interleukin-8 (IL-8) siRNA via CPLA-IL-8 siRNA nanoplexes. The CPLAs possess remarkable hydrolytic degradability, and their cytotoxicity is relatively low. The CPLA-IL-8 siRNA nanoplexes can be readily taken up by prostate cancer cells, resulting in significant IL-8 gene silencing. It is found that the degradability and cytotoxicity of CPLAs, as well as the transfection efficiency of the CPLA-IL-8 siRNA nanoplexes, positively correlate with the amine mol% of CPLAs.

Nanoparticles internalized by cells are valuable probes for bioimaging. In particular, nanoparticles can be detected in "biological transmission window," i.e., near infra- red region. Here, we report a preparation of biotargeting dieth- ylthiatricarbocyanine iodide (DTTC)-functionalized gold nanorods, utilized for detection of malignant cells. These bio- targeting DTTC-functionalized gold nanorods are efficiently internalized into cultured cells and can serve as probes for surface-enhanced Raman scattering (SERS) and dark-field im- aging. The robust SERS signal from malignant cells has clearly demonstrated a signature peak of DTTC in the presence of our formulation. A short acquisition time, we used in this experi- ment, is able to exclude bulk of Raman signal from natural cellular constituents. This signature peak will be a key of identifying cancer due to cancer-specific property of biotar- geted molecule. The results are leading to promising real-time cancer detection. In addition, these multimodal probes demon- strated low toxicity in cell viability studies which enables a broad range of multiplex imaging applications. Keyword In vitro nanoprobe .Multiplex imaging .SERS . Gold nanorods

Theranostic platform integrating diagnostic imaging and therapeutic function into a single system has become a new direction of nanoparticle research. In the process of treatment, therapeutic efficacy is monitored. The use of theranostic nanoparticle can add an additional "layer" to keep track on the therapeutic agent such as the pharmacokinetics and biodistribution. In this report, we have developed quantum rod (QR) based formulations for the delivery of small interfering RNAs (siRNAs) to human neuronal cells. PEGlyated QRs with different surface functional groups (amine and maleimide) were designed for selectively down-regulating the dopaminergic signaling pathway which is associated with the drug abuse behavior. We have demonstrated that the DARPP-32 siRNAs were successfully delivered to dopaminergic neuronal (DAN) cells which led to drastic knockdown of specific gene expression by both the electrostatic and covalent bond conjugation regimes. The PEGlyated surface offered high biocompatibilities and negligible cytotoxicities to the QR formulations that may facilitate the in vivo applications of these nanoparticles. Published Version

We report the use of biocompatible gold nano- rods (GNRs) as multimodal (plasmonic and magnetic) probes for cancer cell labeling in vitro. These multifunc- tional and multimodal bioconjugates were prepared by replacing cetyltrimethylammonium bromide with a mixture of functionalized PEGylation molecules so that a variety of functionalities (e.g., magnetic resonance imaging agent gadolinium (Gd) and biorecognition molecule transferrin (Tf)) can be easily integrated using simple chemistry. It was shown that Gd incorporation did not interfere with the plasmonic properties of the GNRs and a strong T1 relaxivity was estimated (10.0 mM �1 s �1 ), which is more than twice that of the clinical MRI agent Gd-DTPA. The large observed T1 relaxivity was possibly due to the huge surface to volume ratio of GNR, which allowed huge amount of amine-terminated molecule to anchor on the surface, coupled with Gd (III) ions for the enhanced relaxation of water protons. Pancreatic cancer cell over- expressing the transferring receptor was served as the in vitro model, and the Tf-mediated uptake was demonstrated and confirmed by dark-field imaging and transmission electron microscopy. More importantly, cell viability (MTS) assay did not reveal any sign of toxicity in these treated cells, suggesting that PEGylated GNRs can serve as a biocompatible, multifunctional, and multimodal platform for variable bio-applications.

In this contribution, we show that Au NRs functionalized with PEG molecules can be used as absorption nanoprobes for near-infrared imaging in live animals. We have found that the contrast signal of the in vivo image is dependent upon the transmission ability of the NIR light interacting with the different aspect ratios of Au NRs. Our study was focused on absorption in vivo imaging at 700 nm, which is within the transmission window of the skin. NIR absorption in vivo imaging was carried out by subcutaneous injection of mice with PEGylated Au NRs that have a LSPR around 700 nm. The formulation showed strong contrast signals under the tissues upon irradiation with NIR light. More importantly, our theoretical calculation suggested that the high contrast signals from the PEGylated Au NRs were generated via the NIR light absorption of the Au NRs within the tissue.

The need of mobile microscope is escalating as well as the demand of high quality optical components in low price. We report here a novel needle moving technique to fabricate milli-size lens together with thermal assist moldless method. Our proposed protocol is able to create a high tensile strength structure of the lens and its base which is beneficial for exploiting in convertinga smart phone to be a digital microscope. We observe that no bubble trapped in a lens when this technique is performed which can overcome a challenge problem found in a typical dropping technique. We demonstrate the symmetry, smoothness and micron-scale resolution of the fabricated structure. This proposed technique is promising to serve as high quality control mass production without any expensive equipment required.

In this paper, we report the synthesis of FGF-2 peptide labeled luminescent nanocrystals as optical probes for targeted imaging of live neuroblastoma cells. Confocal laser scanning microscopy technique was used to confirm the receptor-mediated uptake of the bioconjugates into the live neuroblastoma cells and study the dynamic profile of the bioconjugates within a single cell. It was found that the bioconjugates were self-assembled near the nuclear periphery after they entered the cellular cytoplasm. In addition to confocal imaging, the cytotoxicity of bioconjugates was investigated using colorimetric cell viability (MTS) assay. The MTS study reveals that the bioconjugate formulation has very low toxicity. These results demonstrate that the luminescent nanocrystal bioconjugates can serve as biocompatible targeted probes for multiplex cell labeling and molecule tracking.

We introduce a mechanical approach to phase transfer of PEGylated gold nanorods. Amphiphilic PEG ligands can be switched between hydrophilic and hydrophobic states by applying mechanical force. PEG-GNRs in their hydrophobic state self-assemble into rings, a phenomenon previously observed only for GNRs capped with hydrophobic ligands.