An immunosorbent assay system was integrated into a glass microchip. Polystyrene beads were introduced into a microchannel, and then human secretory immunoglobulin A (s-IgA) adsorbed on the bead surface was reacted with colloidal gold conjugated anti-s-IgA antibody and detected by a thermal lens microscope. The scale merits of liquid microspace on the molecular behavior remarkably contributed to reduced assay time. The integration cut the time necessary for the antigen-antibody reaction by 1/90, thus shortening the overall analysis time from 24 h to less than 1 h. Moreover, troublesome operations required for conventional immunosorbent assays could be replaced by simple operations.

We have established a novel immunotherapeutic approach involving dendritic cells (DCs) with potent immunoregulatory property (designated as regulatory DCs [rDCs]) for acute graft-versus-host disease (GVHD) and leukemia relapse in allogeneic bone marrow (BM) transplantation (BMT) in mice bearing leukemia. rDCs displayed high levels of MHC molecules and extremely low levels of costimulatory molecules. A single injection of rDCs following allogeneic BMT controlled the ability of the transplanted T cells to induce acute GVHD and graft-versus-leukemia (GVL) effect in the recipients bearing leukemia, and that resulted in protection from the lethality caused by acute GVHD and tumor burden. Thus, the use of rDCs may be therapeutically useful for the treatment of acute GVHD and leukemia relapse in allogeneic BMT.

A new design and construction methodology for integration of complicated chemical processing on a microchip was proposed. This methodology, continuous-flow chemical processing (CFCP), is based on a combination of microunit operations (MUOs) and a multiphase flow network. Chemical operations in microchannels, such as mixing, reaction, and extraction, were classified into several MUOs. The complete procedure for Co(II) wet analysis, including a chelating reaction, solvent extraction, and purification was decomposed into MUOs and reconstructed as CFCP on a microchip. Chemical reaction and molecular transport were realized in and between continuous liquid flows in a multiphase flow network, such as aqueous/aqueous, aqueous/organic, and aqueous/organic/aqueous flows. When the determination of Co(II) in an admixture of Cu(II) was carried out using this methodology, the determination limit (2sigma) was obtained as 18 nM, and the absolute amount of Co chelates detected was 0.13 zmol, that is, 78 chelates. The sample analysis time was faster than that of a conventional processing system. Moreover, troublesome operations such as phase separation and acid and alkali washing, all necessary for the conventional system, were simplified. The CFCP methodology proposed here can be applied to various on-chip applications.