Photodynamic therapy (PDT) is an effective method for the treatment of superficial and early-stage cancers. The use of DDS for the delivery of photosensitizers is a promising approach for improved safety and enhanced efficacy of PDT. In this regard, we have developed polymeric micelles incorporating dendritic photosensitizers and demonstrated their usefulness in animal studies.
Also, we have established an innovative PDT system using the combination of polymeric micelles and light irradiation device for diagnosis and treatment of microcarcinoma.

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Ultrasound has a great potential to be a modality of low invasive cancer treatment of deep-seated tissues such as liver with relatively small equipment size. To overcome the problems of currently available ultrasound cancer treatment systems, we have proposed a cancer treatment method which utilizes a nano-sized particle. The particle, phase-change nano-droplet (PCND), is a precursor of microbubble and exposing a 'phase-change pulse' turns it to a microbubble where needed. The resulting microbubble works as a contrast agent and a therapy sensitizer for ultrasound. We haven established a way to prepare such PCND and investigated if it works as a contrast agent and a therapy sensitizer. Experiments with rats and mice exhibited that our PCND plays the two roles in vivo with systemic administration. We believe these results will lead to a new generation of low invasive cancer treatment.

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Recently, ultrasound-mediated drug or gene delivery with microbubbles was developed as a novel DDS technology. However, an optimum carrier of this system is not yet established. So, we developed novel liposomes (Bubble liposome) containing an ultrasound imaging gas as ultrasound-sensitive carrier in the drug and gene delivery system.
We discuss about the feasibility of Bubble liposome in gene delivery system.

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The cell-killing effect of boron neutron capture therapy (BNCT) is due to the nuclear reaction of two essentially nontoxic species, boron-10 (¹⁰B) and thermal neutrons, whose destructive effect is well observed in boron-loaded tissues. Therefore, the high accumulation and selective delivery of ¹⁰B into the tumor tissue are the most important requirements to achieve efficient neutron capture therapy for cancer. BNCT has been applied clinically for the treatment of malignant brain tumors, malignant melanoma, head and neck cancer, and hepatoma using two boron compounds:sodium borocaptate (¹⁰BSH) and L-p-boronophenylalamine (L-¹⁰BPA). These low molecule compounds are easily cleared from the cancer cells and blood, therefore, high accumulation and selective delivery of boron compounds into tumor tissues are most important to achieve effective BNCT and to avoid damage of adjacent healthy cells. Recently, much attention has been focused on liposomal drug delivery system as an attractive intelligent technology of targeting and controlled release of ¹⁰B compounds.
In this review, recent development of liposomal boron delivery system is summarized.

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Fusion between external stimuli and drug carrier technologies is extremely attractive as the next generation of targeted drug delivery, which can achieve a site-selective drug action at target tissues and organs. Among several external stimuli, the use of temperature-responsive system is attractive due to both a low invasiveness to non-target normal tissues and the facile development of medical external energy irradiation devices.
In this review, the author presents the molecular design and unique properties of various thermoresponsive drug carrier systems, which can achieve spatial and temporal drug modulation at target sites by combining with external heating devices, such as hyperthermia.

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