H. Horinaka

PEG-Attached PAMAM Dendrimers Encapsulating Gold Nanoparticles: Growing Gold Nanoparticles in the Dendrimers for Improvement of Their Photothermal Properties

Recently, we demonstrated that loading of HAuCl(4) in poly(ethylene glycol) (PEG)-attached poly(amidoamine) (PAMAM) G4 dendrimers and subsequent reduction with NaBH(4) yield dendrimers encapsulating gold nanoparticles (Au NPs), which have photoinduced heat-generating properties. This study was undertaken to enhance photothermal properties of the Au NP-incorporated PEG-attached dendrimers by growing Au NPs in the dendrimers. Repeated loading of HAuCl(4) in the PEG-attached dendrimers and subsequent reduction with NaBH(4) enhanced the surface plasmon resonance, indicating that Au NPs were grown in the PEG-attached dendrimers using that procedure. Transmission electron microscopy (TEM) analysis revealed that the size of Au NPs formed in the dendrimers increased with the number of repetitions of HAuCl(4) loading and subsequent reduction in the dendrimers, although the size distribution of the Au NPs remained narrow. The photoinduced-heat generation capability of the Au NPs-encapsulating dendrimers increased as the Au NPs grew. These dendrimers with Au NPs exhibited strong cytotoxicity against HeLa cells under visible light irradiation. The result demonstrates that PEG-attached dendrimers encapsulating the grown Au NPs might be useful as devices for target-specific therapy when used with light irradiation.

Optically assisted ultrasonic velocity-change images of visceral fat in a living animal

Noninvasive imaging method by detection of ultrasonic velocity change was proposed for diagnosis of visceral fat. The ultrasonic velocity-change images of the fat distribution in the excised rabbit lever and living rabbit lever. Experimental results suggest that this imaging method can be applied to a practical monitor of the visceral fat in a living human body.

P3D-5 Real Time Optical Tomography of Biological Tissue by Detection of Ultrasonic Velocity Change Due to Light Illumination

The ultrasonic velocity change induced by light was measured quickly by the remodeled commercial-type ultrasonic equipment with the multi-array transducer in order to investigate a practical optical tomography for medical diagnosis. The 3D view of the optical absorption region in the tissue mimic phantom was obtained by ultrasonic velocity change imaging

P5B-11 Monitoring Device of Au Nano-Particle Distribution in Living Body Using Ultrasonic Velocity Change Image

We could obtain ultrasonic velocity change images of Au nano-particles in the two phantoms which ware made of highly optical scattering ager and the chicken breast meet by using the remodeled diagnostic ultrasound equipment. All experimental results suggested that our imaging method could be applied to a practical monitor for the thermal therapy and the drug delivery system (DDS), and could be applied to biomaterial identification.

Tissue characterization using optically assisted ultrasonic velocity-change imaging method

Two kind of methods using the spectroscopic information of the materials and the dependence of ultrasonic velocity-change on temperature were investigated to indentify the distribution of objective material in the biological tissue. Experimental results showed the possibility that the biological tissue could be characterized using the optically assisted ultrasonic velocity-change imaging method.

Spectroscopic imaging of nano-particle distribution in biological tissue using optically assisted ultrasonic velocity-change detection

The optically assisted ultrasonic velocity-change imaging method was applied to obtain the spectroscopic image of nano-particles, which were expected as markers for drug delivery system and photo-thermal therapy, in tissue mimic phantoms. Phantoms including gold nano-rods or semiconductor nano-particles were prepared. The ultrasonic velocity-change images of phantoms were obtained using illumination of laser diodes with various emission wavelengths corresponded to the absorption spectrum of nano-particle. Experimental results showed that our method has the potential to find the optical absorption agent in biological tissue.

Simple method for measuring timing-jitter in a gain-switched DFB laser using delayed optical feedback

A simple method for measuring timing-jitter in a gain-switched distributed-feedback laser using delayed optical feedback was proposed. Using this, the timing-jitter in a gain-switched pulse-train was estimated to be 26 ps without using high-speed equipment.

Imaging of visceral fat in living rabbit by using detection of ultrasonic velocity change

Development of the noninvasive imaging equipment for the diagnosis of visceral fat in the early stage has been eagerly anticipated. The ultrasonic velocity-change imaging method was applied to living rabbits fed on the standard diet and that on the high fat diet. Experimental results show that the ultrasonic velocity-change images give the information about the fat accumulation level in liver of rabbit. The ultrasonic velocity-change imaging method has possible application to the diagnosis of fatty liver in a living human body.

New Imaging Method by Using Ultrasound Velocity Change Caused by Optical Absorption

We measured optical absorption images of phantoms using our new method that detects ultrasonic velocity change caused by light illumination. The electric scan function of the remodeled diagnostic ultrasonic equipment quickly constructed the ultrasonic velocity change images. The spectroscopic information of phantoms was also obtained from the dependence of ultrasonic velocity change image on the wavelength of the tunable laser used for illumination. It was suggested that our method had the potential to monitor biomarkers used in drug-delivery systems.

Reconstruction Image of Au Nanoparticle Distribution Within Scattering Medium Using Ultrasonic Velocity Change Imaging

Aiming at a realization of effective and less invasive cancer screening tests and therapies using Au nanoparticles which tend to aggregate around cancer parts, the distributional region of Au nanoparticles within a scattering medium of agar was detected by applying an image reconstruction method of the ultrasonic velocity change imaging.