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Hollow Interior (hollow + interior)

Distribution by Scientific Domains

Polymers and Materials Science	75%

Selected Abstracts

Fabrication of Microbeads with a Controllable Hollow Interior and Porous Wall Using a Capillary Fluidic Device

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2009
Sung-Wook Choi
Abstract Poly(D,L -lactide-co-glycolide) (PLGA) microbeads with a hollow interior and porous wall are prepared using a simple fluidic device fabricated with PVC tubes, glass capillaries, and a needle. Using the fluidic device with three flow channels, uniform water-in-oil-in-water (W-O-W) emulsions with a single inner water droplet can be achieved with controllable dimensions by varying the flow rate of each phase. The resultant W-O-W emulsions evolve into PLGA microbeads with a hollow interior and porous wall after the organic solvent in the middle oil phase evaporates. Two approaches are employed for developing a porous structure in the wall: emulsion templating and fast solvent evaporation. For emulsion templating, a homogenized, water-in-oil (W/O) emulsion is introduced as the middle phase instead of the pure oil phase. Low-molecular-weight fluorescein isothiocyanate (FITC) and high-molecular-weight fluorescein isothiocyanate,dextran conjugate (FITC,DEX) is added to the inner water phase to elucidate both the pore size and their interconnectivity in the wall of the microbeads. From optical fluorescence microscopy and scanning electron microscopy images, it is confirmed that the emulsion-templated microbeads (W-W/O-W) have larger and better interconnected pores than the W-O-W microbeads. These microstructured microbeads can potentially be employed for cell encapsulation and tissue engineering, as well as protection of active agents. [source]

A New Photothermal Therapeutic Agent: Core-Free Nanostructured AuxAg1,x Dendrites

CHEMISTRY - A EUROPEAN JOURNAL, Issue 10 2008
Kuo-Wei Hu
Abstract A new class of AuxAg1,x nanostructures with dendrite morphology and a hollow interior were synthesized by using a replacement reaction between Ag dendrites and an aqueous solution of HAuCl4. The Ag nanostructured dendrites were generated by the reaction of AgNO3 with ascorbic acid in a methanol/water system. The dendrites resemble a coral shape and are built up of many stems with an asymmetric arrangement. Each stem is approximately 400,nm in length and 65,nm in diameter. The bimetallic composition of AuxAg1,x can be tuned by the addition of different amounts of HAuCl4 to the Ag dendritic solution. The hollowing process resulted in tubular structures with a wall thickness of 10.5,nm in Au0.3Ag0.7 dendrites. The UV/Vis spectra indicate that the strongest NIR absorption among the resulting hollow AuxAg1,x dendrites was in Au0.3Ag0.7. The MTT assay was conducted to evaluate the cytotoxicity of Ag dendrites, hollow Au0.06Ag0.94 and Au0.3Ag0.7 dendrites, and Au nanorods. It was found that hollow Au0.06Ag0.94 and Au0.3Ag0.7 dendrites exhibited good biocompatibility, while both Ag dendrites and Au nanorods showed dose-dependent toxicity. Because of absorption in the NIR region, hollow Au0.3Ag0.7 dendrites were used as photothermal absorbers for destroying A549 lung cancer cells. Their photothermal performance was compared to that of Au nanorod photothermal therapeutic agents. As a result, the particle concentration and laser power required for efficient cancer cell damage were significantly reduced for hollow Au0.3Ag0.7 dendrites relative to those used for Au nanorods. The hollow Au0.3Ag0.7 nanostructured dendrites show potential in photothermolysis for killing cancer cells. [source]

Hollow Inorganic Nanospheres and Nanotubes with Tunable Wall Thicknesses by Atomic Layer Deposition on Self-Assembled Polymeric Templates,

ADVANCED MATERIALS, Issue 1 2007

The construction of inorganic nanostructures with hollow interiors is demonstrated by coating self-assembled polymeric nano-objects with a thin Al2O3 layer by atomic layer deposition (ALD), followed by removal of the polymer template upon heating. The morphology of the nano-object (i.e., spherical or cylindrical) is controlled by the block lengths of the copolymer. The thickness of the Al2O3 wall is controlled by the number of ALD cycles. [source]