Hsiu-Mei Lin

Synthesis of copper nanowire decorated reduced graphene oxide for electro-oxidation of methanol

Hierarchical copper nanowires (Cu NWs) having structures of rose-like stems with nano-thorns, with an average length and width of 6 ± 4 μm and 100 ± 15 nm, respectively, are prepared through a simple hydrothermal approach. In the presence of catechin, nano-thorn growth readily occurs from the side faces (200) of rose-like stems that are partially covered with ethylenediamine (EDA) that acts as a complexing agent for Cu2+. The size and morphology of Cu NWs are highly dependent on the concentrations of catechin, EDA, and reaction time. The hydrothermal approach is further applied to the preparation of a Cu NW decorated reduced graphene oxide (Cu NW@RGO) composite in the presence of graphene oxide (GO) and catechin as a reducing agent. The Cu NWs in Cu NW@RGO have a similar structure to that of Cu NWs prepared in bulk solution, with an average length and width of 4 ± 2 μm and 200 ± 4 nm, respectively. The Cu NW@RGO relative to Cu NWs has greater dispersion in aqueous solution, mainly because of greater hydrophilicity of RGO than Cu NW. The Cu NW@RGO-GCE relative to the bare glassy carbon electrode (GCE) (236 Ω) and Cu NW-GCE (322 Ω) has a small charge transfer resistance value (87 Ω), because of the facile electron transfer ability and good conductivity provided by RGO. The Cu NW@RGO composite featuring low-cost, high durability, low onset potential (ca. 0.48 V) and high mass activity (1.11 mA μg−1) exhibits a superior catalytic activity for methanol oxidation in an alkaline medium.

Organic–Inorganic Hybrid Zinc Phosphate with 28‐Ring Channels

An organic-inorganic hybrid zinc phosphate with 28-ring channels was synthesized by use of an organic ligand instead of organic amine template under a hydro(solvo)thermal condition. This crystalline zinc phosphate contains large channels constructed from 28 zinc and phosphate tetrahedral units. The walls of the channels consist of two types of zincophosphate chains, in which the Zn atoms are coordinated by 2,4,5-tri(4-pyridyl)-imidazole ligands as pendent groups. This compound exhibits yellow emission and interesting properties of removing cobalt, cadmium, and mercury cations from aqueous solution. A new two-dimensional organic-inorganic hybrid zincophosphate was also obtained by changing the solvent mixture ratios in the synthesis.

New nanostructured zinc phosphite templated by cetyltrimethylammonium cations: synthesis, crystal structure, adsorption, and photoluminescence properties.

Nanostructured zinc phosphite templated by cetyltrimethylammonium (CTA(+)) cations was synthesized using a hydro(solvo)thermal method. This is the first example of a crystalline metal phosphite containing long carbon tails of the CTA(+) ions as templates in its structure, as is structurally characterized by single-crystal X-ray diffraction. The 2D inorganic structures with 4.8(2) topologies are constructed from the interconnection of tetrahedral ZnO3Br and HPO3 units, which are sandwiched between CTA(+) ion surfactants in a packing behavior of a largely lamellar liquid-crystalline structure to extend the interlayer d spacing to 28.05 Å. Adsorption experiment shows selective adsorption properties of 1-naphthol and a adsorption capacity of 0.17 mmol/mmol (CTA)ZnBr(HPO3). This compound has potential as an adsorbent for the removal of 1-naphthol pollutant from wastewater. In addition, the naphthol-adsorbed sample shows interesting luminescent properties that are different from that of an as-synthesized sample. The crystal structure, thermal stability, IR spectrum, adsorption, and photoluminescence properties have been studied.

Hierarchically biomimetic scaffold of a collagen–mesoporous bioactive glass nanofiber composite for bone tissue engineering

Mesoporous bioactive glass nanofibers (MBGNFs) were prepared by a sol-gel/electrospinning technique. Subsequently, a collagen-MBGNF (CM) composite scaffold that simultaneously possessed a macroporous structure and collagen nanofibers was fabricated by a gelation and freeze-drying process. Additionally, immersing the CM scaffold in a simulated body fluid resulted in the formation of bone-like apatite minerals on the surface. The CM scaffold provided a suitable environment for attachment to the cytoskeleton. Based on the measured alkaline phosphatase activity and protein expression levels of osteocalcin and bone sialoprotein, the CM scaffold promoted the differentiation and mineralization of MG63 osteoblast-like cells. In addition, the bone regeneration ability of the CM scaffold was examined using a rat calvarial defect model in vivo. The results revealed that CM is biodegradable and could promote bone regeneration. Therefore, a CM composite scaffold is a potential bone graft for bone tissue engineering applications.

Preparation, characterization, and in vitro evaluation of folate-modified mesoporous bioactive glass for targeted anticancer drug carriers

Functionalized mesoporous bioactive glasses (MBGs) with folic acid (FA) were evaluated specifically for targeting cancer cells because of the high abundance of folate receptors (FRs) in numerous cancer cells. The folate-modified MBG (MBG-FA) was used as a targeted anticancer drug delivery carrier to investigate receptor-mediated targeting characteristics. At the same time, in vitro cytotoxicity and cell uptake of FA-grafted MBG (MBG-FA) to HeLa and L929 cell lines were evaluated. MBG-FA was nontoxic up to a concentration of 200 μg mL-1, and can be specifically raised by HeLa and L929 cells through FA receptor-mediated endocytosis. In vitro cellular uptakes of MBG-FA were investigated with a fluorescence microscope, which demonstrates considerably higher internalization of the MBG-FA by HeLa epithelial carcinoma cells, which are overexpressed folate receptors (FRs), than the cellular uptake by L929 fibroblast cells, which are deficient folate receptors (FRs). Camptothecin (CPT), a water-insoluble anticancer drug, was delivered into cancer cells; surface conjugation with cancer-specific targeting agents increased the uptake into cancer cells relative to non-cancerous fibroblasts. CPT had a sustained release pattern from MBG-FA, and the CPT-loaded MBG-FA exhibited greater cytotoxicity than free CPT because of the increased cell uptake of anticancer drug delivery vehicles mediated by the FA receptor. The structural, morphological, and textural features were characterized well by X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 adsorption/desorption. The results reveal that the MBG exhibited typical ordered characteristics of the hexagonal mesostructure. Therefore, this study concludes that the MBG-FA system demonstrates great potential in the targeted intelligent drug delivery systems (DDSs) and cancer-therapy fields.

New 3 D Tubular Porous Structure of an Organic-Zincophosphite Framework with Interesting Gas Adsorption and Luminescence Properties

A new 3D tubular zinc phosphite, Zn2 (C22 H22 N8 )0.5 (HPO3 )2 ⋅H2 O (1), incorporating a tetradentate organic ligand was synthesized under hydro(solvo)thermal conditions and structurally characterized by single-crystal X-ray diffraction. Compound 1 is the first example of inorganic zincophosphite chains being interlinked through 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene to form a tubular porous framework with unusual organic-inorganic hybrid channels. The thermal and chemical stabilities, high capacity for CO2 adsorption compared to that for N2 adsorption, and interesting optical properties of LED devices fabricated using this compound were also studied.

Ultraviolet and visible random lasers assisted by diatom frustules

Random laser actions in ultraviolet and visible regions have been demonstrated based on the composites consisting of bio-inspired diatom frustules. Owing to the low optical loss derived from porous network of diatom structures, we report wide spectrum range random lasers arising from GaN film and Rh6G dye via using biological diatoms as scattering centers. Interestingly, both ultraviolet and visible-range random laser actions with very sharp peaks can be easily obtained, with the average length of optics cavity closed to the average size of diatom frustules in both cases, indicating the excellent optical confinement of diatom frustules. It is expected that the first proof of concept shown here can pave an avenue toward future broad-range random lasers and eco-friendly biophotonics devices with high performance and wide spectrum response.

Two Polymorphs of an Organic-Zincophosphate Incorporating a Terephthalate Bridging Ligand in an Unusual Bonding Mode.

Two new polymorphs of a zinc phosphate incorporating the terephthalate organic ligand 1,4-benzenedicarboxylate (BDC), (H2DA)Zn2(cis-BDC)(HPO4)2 (1) and (H2DA)Zn2(trans-BDC)(HPO4)2 (2), where DA = 1,7-diaminoheptane, were synthesized via a hydro(solvo)thermal method at different reaction temperatures and structurally characterized by single-crystal X-ray diffraction. Interestingly, the BDC ligands, which adopt the bis-monodentate coordination model with a unusual cis type for compound 1 and with a trans linkage for compound 2, bridge the Zn atoms of the inorganic layers in the generation of two polymorphs with structural diversities (one kind of arrangement of the layered zincophosphate layer in 1; the flat and zigzag sheets of inorganic networks in 2). A simple method for tuning the optical luminescence of the title compound from blue, red, green, yellow, and pink to white emission by stirring powdered samples in lanthanide-cation-containing aqueous ethanol solutions at room temperature for 1-2 h is also presented.

Conversion of Biowaste Asian Hard Clam (Meretrix lusoria) Shells into White-Emitting Phosphors for Use in Neutral White LEDs

The increasing volume and complexity of waste associated with the modern economy poses a serious risk to ecosystems and human health. However, the remanufacturing and recycling of waste into usable products can lead to substantial resource savings. In the present study, clam shell waste was first transformed into pure and well-crystallized single-phase white light-emitting phosphor Ca9Gd(PO4)7:Eu2+,Mn2+ materials. The phosphor Ca9Gd(PO4)7:Eu2+,Mn2+ materials were synthesized by the solid-state reaction method and the carbothermic reduction process, and then characterized and analyzed by means of X-ray diffraction (XRD) and photoluminescence (PL) measurements. The structural and luminescent properties of the phosphors were investigated as well. The PL and quantum efficiency measurements showed that the luminescence properties of clam shell-based phosphors were comparable to that of the chemically derived phosphors. Moreover, white light-emitting diodes were fabricated through the integration of 380 nm chips and single-phase white light-emitting phosphors (Ca0.979Eu0.006Mn0.015)9Gd(PO4)7 into a single package of a white light emitting diode (WLED) emitting a neutral white light of 5298 K with color coordinates of (0.337, 0.344).

Effects of a thermally stable chlorophyll extract from diatom algae on surface textured Si solar cells

We present the effects of a chlorophyll extract from diatom algae as a spin-coating anti-reflection layer on surface textured silicon solar cells. The diatom extract with a refractive index value in-between Si and air can suppress the overall light reflection from the bare Si surface up to 7% over spectral regions of 350–1100 nm. Additionally, it also shows a strong photon downconversion effect within the visible light regime. Based on both optical characteristics, the short circuit current density is largely enhanced for an approximately 10% increment in the cell efficiency. Additionally, the diatom extract is also thermally stable up to 90 °C without apparent color change and any degradation of optical properties. Thus, the presented approach is simple, doable, suitable for large area application, and more importantly, it is eco-friendly.