We isolated a new (second) isomer of Ca@C72. As a result of this discovery, it was confirmed that at least one of the two Ca@C72 isomers has a C72 cage that does not satisfy the so-called isolated pentagon rule (IPR), because C72 has only one IPR cage structure.

We have developed a single-step method for selectively extracting endohedral metallofullerenes. In this new method, a mixed solvent of triethylamine and acetone is used to extract endohedral metallofullerenes from raw soot. The efficiency of extraction was investigated by extracting Ce-containing metallofullerenes, Ce@C82 and Ce2@C80, from raw soot obtained by an arc discharge technique. The resultant extract contained little or no empty fullerenes such as C60 or C70, that is, the Ce-metallofullerenes were selectively extracted.

The development of immunoadsorbents that have high specificity for immunoglobulin and no immunogenicity is essential for immunoadsorption treatment of autoimmune diseases. In this study, we designed peptide immunoadsorbents by molecular grafting of the IgG-Fc binding epitopes of Protein A onto a de novo-designed helix-loop-helix peptide. Linear (linG7A5) and cyclic (cyG7A5) grafted peptides were synthesized to test their binding affinity and specificity. Peptide cyG7A5 demonstrated high specificity for human IgG-Fc, with a K(D) of 19 μM, and demonstrated no affinity to other plasma proteins, human serum albumin, or fibrinogen. To evaluate their immunoadsorbance efficiency, the grafted peptides and Protein A were conjugated to polyvinyl acetate resin and tested in a batch-wise process for adsorption removal of IgG from human plasma. The IgG capture capacities of the peptides correlated well with their binding affinities. Interestingly, cyG7A5 showed a higher binding specificity for IgG than did Protein A.