Cationic and anionic cyclophanes bearing a biotin moiety were synthesized as a water-soluble host (1a and 1b, respectively). Both hosts 1a and 1b were found to strongly bind avidin with binding constants of 1.3 × 108 M–1, as confirmed by surface plasmon resonance measurements. The present conjugate of 1a with avidin (1a-avidin) showed an enhanced guest binding affinity toward fluorescence guests such as TNS and 2,6-ANS. The K values of 1a-avidin conjugate with TNS and 2,6-ANS were ∼19-fold larger than those of monocyclic cyclophane 1a with the identical guests. Favorable hydrophobic and electrostatic interactions between 1a-avidin and TNS were suggested by computer-aided molecular modeling calculations. Moreover, addition of excess biotin to the complexes of 1a-avidin with the guests resulted in dissociation of 1a-avidin to avidin and 1a having less guest-binding affinity. Conversely, such enhancements in the guest-binding affinity were not obviously observed for the conjugate of anionic 1b with avidin (1b-avidin) due to electrostatic repulsion between anionic 1b and anionic guests.

Coumarin-appended cyclophanes bearing positively or negatively charged side chains were synthesized as a water-soluble host (1a or 1b, respectively). Host 1a and 1b showed fluorescence bands with fluorescence maxima at 404 nm originated from coumarin moiety. As a host for guest molecules by using macrocyclic cavity, cationic host 1a binds anionic guests such as 6-p-toluidinonaphthalene-2-sulfonate (TNS), 6-anilinonaphthalene-2-sulfonate (2,6-ANS), and 8-anilinonaphthalene-1-sulfonate (1,8-ANS) more strongly than anionic host 1b, reflecting intermolecular electrostatic interactions. In addition, both host 1a and 1b showed protein surface recognition and fluorescence response toward myoglobin, a small and globular protein. The fluorescence intensity originating from the hosts decreased upon the addition of myoglobin, reflecting the formation of 1a-and 1b-myoglobin complexes. On the other hand, such fluorescence response of 1a and 1b was almost negligible for other proteins such as egg white albumin, bovine serum albumin, human albumin, concanavaline A, fibrinogen, c-globlin, peanut agglutinin, trypsin, and lysozyme.

The Japanese welfare system has undergone rapid change. A law has been enacted that requires the handicapped to work in order to be independent from government assistance. However, it is difficult for the intellectually disabled (ID) to earn a living wage because of a lack of understanding with respect to their ability and communication skills. Our organization conducts business with ID individuals such as those with autism. The business model for the income of our organization and the ID individuals concerned was successfully constructed through an understanding and application of the characteristics of ID individuals. This paper shows the current environment affecting the ID and presents our strategic and successful business model that is designed to enable them to achieve a realistic livelihood.