Printed Organic Transistor-based Biosensors for Non-invasive Sweat Analysis.

This review describes recent advances in biosensors for non-invasive human healthcare applications, especially focusing on sweat analysis, along with approaches for fabricating these biosensors based on printed electronics technology. Human sweat contains various kinds of biomarkers. The relationship between a trace amount of sweat biomarkers partially partitioned from blood and diseases has been investigated by omic analysis. Recent progress in wearable or portable biosensors has enabled periodic or continuous monitoring of some sweat biomarkers while supporting the results of the omic analysis. In this review, we particularly focused on a transistor-based biosensor that is highly sensitive in quantitatively detecting the low level of sweat biomarkers. Furthermore, we showed a new approach of flexible hybrid electronics that has been applied to advanced sweat biosensors to realize fully integrated biosensing systems wirelessly connected to a networked IoT system. These technologies are based on uniquely advanced printing techniques that will facilitate mass fabrication of high-performance biosensors at low cost for future smart healthcare.

Noninvasive Sweat-Lactate Biosensor Emplsoying a Hydrogel-Based Touch Pad.

This study is the first report demonstrating proof-of-concept for a hydrogel-based touch sensor pad used for the non-invasive extraction and detection of sweat components. The sensor device was composed of an electrochemical L-lactate biosensor covered with an agarose gel in a phosphate buffer saline. When human skin contacts the agarose gel, L-lactate in sweat was continuously extracted into the gel, followed by in-situ potentiometric detection without controlled conditions. This novel type of sweat sensor is expected to enable the simple, non-invasive daily periodic monitoring of sweat biomarkers for advanced personal healthcare methods in the future.

Distinct contributions of vacuolar Qabc- and R-SNARE proteins to membrane fusion specificity.

In eukaryotic endomembrane systems, Qabc-SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) on one membrane and R-SNARE on the opposing membrane assemble into a trans-QabcR-SNARE complex to drive membrane fusion. However, it remains ambiguous whether pairing of Qabc- and R-SNAREs mediates membrane fusion specificity. Here, we explored the fusion specificity of reconstituted proteoliposomes bearing purified SNAREs in yeast vacuoles and other organelles. We found that not only vacuolar R-SNARE Nyv1p but also the non-cognate R-SNAREs, endosomal Snc2p, and endoplasmic reticulum-Golgi Sec22p caused efficient fusion with vacuolar Qabc-SNAREs. In contrast, their fusion is blocked completely by replacing vacuolar Qc-SNARE Vam7p with the non-cognate endosomal Tlg1p and Syn8p, although these endosomal Qc-SNAREs fully retained the ability to form cis-SNARE complexes with vacuolar SNAREs in solution and on membranes. Thus, our current study establishes that an appropriate assembly of Qabc-SNAREs is crucial for regulating fusion specificity, whereas R-SNARE itself has little contribution to specificity.

Potentiation of proliferation of some but not all human colon carcinoma cell lines by immobilized hepatic asialoglycoprotein receptor 1.

Twenty-three human colorectal carcinoma cell lines were examined for the binding of recombinant hepatic asialoglycoprotein receptor 1 (ASGR1), which is known to be exclusively expressed on hepatic parenchymal cells. The effects of the binding were assessed by adhesion to and proliferation on immobilized recombinant ASGR1. Recombinant ASGR1 bound strongly to six cell lines and moderately to 15 cell lines out of 23 lines tested, as shown by flow cytometric analysis. The first six cell lines (group A) also exhibited strong adherence to immobilized ASGR1, whereas 11 of the 15 cell lines of the second group (group B) showed significant adhesion with smaller enhancement by ASGR1 than the cell lines in group A. With a representative cell line (DLD-1 cells categorized in group B), a significant portion of the adhesion was inhibited by preincubation of ASGR1 with asialofetuin, a competitive inhibitor of the carbohydrate recognition by ASGR1. The growth rates of 13 cell lines (two of group A and 11 of group B) were significantly accelerated when they were cultured on immobilized recombinant ASGR1. The results indicate that ASGR is a potential organ-specific microenvironmental factor for colorectal carcinoma growth and metastasis formation in livers.

Properties of blocking and non-blocking monoclonal antibodies specific for human macrophage galactose-type C-type lectin (MGL/ClecSF10A/CD301).

Monoclonal antibodies (mAbs) specific for the human macrophage galactose-type calcium-type lectin (MGL) were established. The recombinant extracellular domain of MGL was used to immunize a mouse, and 10 hybridoma clones were obtained. Binding of recombinant MGL to asialo-bovine submaxillary mucin was shown to be blocked by mAbs MLD-1, 4 and 6. Immunoprecipitation of MGL from lysates of COS-1 cells transfected with MGL cDNA (form 6A) was achieved with mAbs MLD-1, 4, 7, 8 and 16. Chimeric recombinant proteins between human MGL and mouse MGL1 were used to determine the location of the epitopes for these mAbs. mAbs MLD-8, 13, 15 and 16 interacted with the amino terminal side of the conserved WVDGTD sequence immediately upstream of QPD, whereas mAbs MLD-7, 12 and 17 interacted with the other side. mAbs MLD-1, 4, and 6 apparently required both sides of this boundary. mAbs MLD-15 and 16 were shown to recognize the protein products of alternatively spliced mRNA 6A/8A and 6C/8A, having deletions at the boundary of exons 7 and 8, in addition to full length and other spliced forms of MGL (6A, 6B and 6C), whereas the other mAbs bound only full length and forms 6A, 6B and 6C.