Organ Technologies (Japan)

イオン交換は産業界の様々な分野で応用されている技術である。本稿ではイオン交換樹脂の電力発電プラントへの適用と半導体向け電子材料精製への応用を中心に，これまで筆者が関わって来た産業界でのイオン交換技術の応用例について述べると共に，学生時代から日本イオン交換学会の運営まで，筆者が「イオン交換」に関わって来た出来事について記載する。

Two tests were performed to investigate the contamination behavior of bare Si wafers by rinsing them using deionized water (DIW) contaminated with metals at the pg/L-level in a single-wafer cleaning process. First, we found that Al, Ti, Mn, Co, Cu, Sr, and Pb exhibited strong correlations between the metal concentrations in DIW and the wafer surface concentrations under different concentrations in DIW and the same rinse time of 480 min. Second, we observed that the wafer surface concentrations of Al, Ti, Cu, and Pb increased with the rinse time, whereas those of Mn, Co, and Sr were constant at rinse times ranging from 10 to 960 min at metal concentrations of 60 pg/L in DIW. In this test, Cu exhibited a high adsorption ratio on bare Si wafers, even at the pg/L level. These data provide novel insights into wet processes for device manufacturing.

Metal contamination is a critical issue in semiconductor manufacturing processes, where controlling the concentration of metals in the deionized water (DIW) used for wafer rinsing and chemical dilution is necessary. In our previous study, we reported an ultra-trace level measurement method using solid-phase extraction (SPE) with a monolithic resin and inductively coupled plasma mass spectrometry (ICP-MS). However, this method had limitations regarding rapid metal concentration confirmation and contamination risks due to manual processing and sample delivery. This study proposes an on-line metal measurement system that uses an automated SPE technique coupled with ICP-MS to address the shortcomings of the conventional method. The system provides continuous on-site monitoring of ultra-trace metal concentrations in DIW, reducing preconcentration volume by up to 60% compared to the conventional method owing to minimizing contamination by automating all processes. Moreover, the system achieved reliable results similar to the conventional method, high analytical stability, with the relative standard deviations (RSDs) within 5% for a concentration of around 0.05 ng/L (n=4) using a test solution. We also evaluated the metal removal filter as an application of the system mentioned above, simultaneously analyzing multiple elements at the single-pg/L level and confirming the performance of the filter.

The water treatment market using RO membranes has been expanding. Biofouling has become one of the major issues in operating RO systems. Slime control agents are one of effective measure to control biofouling, in the other hand, optimization of their dosage is a big challenge. We have developed the Slime control agent Dosing Control System for RO, which calculates the optimum dosage of chemical according to the biofouling potential of raw water that fluctuates daily. As a result of the demonstration test, we have achieved optimization of membrane cleaning frequency and chemical costs for three projects.

Driveline infection (DLI) following left ventricular assist device (LVAD) implantation remains an unresolved problem. Negative pressure wound therapy (NPWT) promotes wound healing by applying negative pressure on the surface of the wound. Recently, the prophylactic application of NPWT to closed surgical incisions has decreased surgical site infections in various postsurgical settings. Therefore, we evaluated the efficacy and safety of prophylactic NPWT for preventing DLI in patients with LVAD implantation. Prophylactic NPWT was provided to 50 patients who received continuous-flow LVADs as bridge-to-transplant therapy at our institution between May 2018 and October 2020 (NPWT group). The negative pressure dressing was applied immediately after surgery and retained on the driveline exit site for 7 days with a continuous application of -125 mm Hg negative pressure. The primary outcome was DLI within 1 year of LVAD implantation. We compared the rate of DLI incidence in the NPWT group with that in the historical control cohort (50 patients) treated with the standard dressing (SD) who received LVAD implantation between July 2015 and April 2018 (SD group). No severe complications were associated with the NPWT. During the follow-up period, DLI was diagnosed in 16 participants (32%) in the NPWT group and 21 participants (42%) in the SD group. The rates of DLI incidence and freedom from DLI did not differ between groups (p=0.30 and p=0.63). Prophylactic NPWT at the driveline exit site was safe following LVAD implantation. However, it did not significantly reduce the risk of DLI.

Here, we describe the preparation of human organoid-derived intestinal epithelial monolayers for studying intestinal barrier function, permeability, and transport. As organoids represent original epithelial tissue response to external stimuli, these models combine the advantages of expandability of cell lines and the relevance and complexity of primary tissue.

Abstract Patient-derived tumor xenograft (PDX)/organoid (PDO), driven by cancer stem cells (CSC), are considered the most predictive models for translational oncology. Large PDX collections reflective of patient populations have been created and used extensively to test various investigational therapies, including in population-trials as surrogate subjects in vivo. PDOs are recognized as in vitro surrogates for patients amenable for high-throughput screening (HTS). We have built a biobank of carcinoma PDX-derived organoids (PDXOs) by converting an existing PDX library and confirmed high degree of similarities between PDXOs and parental PDXs in genomics, histopathology and pharmacology, suggesting “biological equivalence or interchangeability” between the two. Here we demonstrate the applications of PDXO biobank for HTS “matrix” screening for both lead compounds and indications, immune cell co-cultures for immune-therapies and engineering enables in vitro/in vivo imaging. This large biobank of matched pairs of PDXs/PDXOs across different cancers could become powerful tools for the future cancer drug discovery.