On behalf of the WPI Center for Materials Nanoarchitectonics (MANA), we wish to express our gratitude for the publication of this special issue of Advanced Materials, which highlights the recent research activities of MANA. In this preface, we describe briefly the history, vision, and missions of MANA and then outline its research directions by briefly touching on the contents of the papers published in this special issue.
In 2007, Japan's Ministry of Education, Culture, Sports, Science, and Technology (MEXT) launched the World Premier International Research Center Initiative (WPI Program) to create several frontier research centers in Japan. The aim was to facilitate cutting-edge research by promoting the participation of leading scientists from around the world and by providing an attractive research environment. As one of five such frontier centers in the framework of the WPI Program, MANA was established at the National Institute for Materials Science (NIMS) in October 2007.
The direction of research at MANA is defined by the term ‘nanoarchitectonics’1 contained in the acronym ‘MANA’. But what is nanoarchitectonics? Over the past quarter of a century, many impressive advances have been made due to nanotechnology and it has become an important pillar in the development of new materials. However, to fully develop its potential, nanotechnology needs to continue down the path of innovation. In particular, the conventional analytic aspects of nanotechnology must yield to a certain synthetic approach. This will be conducive to the creation of new functionalities that may be exhibited by nanoscale structural units through their mutual interactions, even though these functionalities are not properties of the isolated units. We coined the term nanoarchitectonics to express this innovation of nanotechnology: it is a technology system aimed at arranging nanoscale structural units—a group of atoms, molecules, or nanoscale functional components—into a configuration that creates a novel functionality through mutual interactions among those units. It should be pointed out that materials nanoarchitectonics targets two hierarchical classes of materials development, i.e., nanomaterial creation and nanosystem organization.
MANA pursues the nanoarchitectonics described above on the basis of five key technologies: i) controlled self-organization, ii) chemical nanomanipulation, iii) field-induced materials control, iv) novel manipulations of atoms and molecules, and v) theoretical modeling and design. These five key technologies of nanoarchitectonics are harnessed for scientific research organized into four fields: 1) Nano-Materials, 2) Nano-Systems, 3) Nano-Green, and 4) Nano-Bio.
In the Nano-Materials field, various novel nanoscale materials have been created by utilizing unique synthetic techniques mostly based on soft-chemical nanoarchitectonics, which includes colloid chemistry and supermolecular nanoarchitectonic processes. In this special issue, four papers (by M. Osada and T. Sasaki; K. Ariga et al.; D. Golberg et al.; Z.-L. Wang) relate to this research field.
Researchers in the Nano-Systems field are exploring how nanoscale structural elements can produce novel functionalities through their mutual interactions, and how such novel functionalities can actually be introduced as materials on the basis of nanoarchitectonics. Six papers in this special issue (by T. Hasegawa et al.; A. Z. Stieg et al.; X. Hu; R. Inoue and H. Takayanagi; T. Minari et al.; C. Joachim et al.) are from this research field.
The innovative Nano-Green field develops new materials which act as electro- and photocatalysts, rechargeable batteries, solar cells, and fuel cells, etc., which are necessary for the realization of a sustainable society. Three papers in this special issue (by H. Tong et al.; E. Fabbri et al.; T. Masuda et al.) relate to the Nano-Green research field.
Finally, the Nano-Bio field has set its research direction towards therapeutic materials, including the development of new materials useful for regenerative medicine. Although only one paper (by M. Ebara et al.) is published in this special issue due to the short time period since the renewal of this research field in MANA, special efforts have already been undertaken to strengthen this important subject.
This special issue of Advanced Materials presents the research activities of MANA over the four years since its establishment in 2007, and we hope that it stimulates collaborations between MANA and other institutions around the world.