Precise Control of the Molecular Arrangement of Organic Semiconductors for High Charge Carrier Mobility.

Organic semiconductors are well-known to exhibit high charge carrier mobility based on their spread of the π-orbital. In particular, the π-orbital overlap between neighboring molecules significantly affects their charge carrier mobility. This study elucidated the direct effect of subtle differences in the π-orbital overlap on charge carrier mobility, by precisely controlling only molecular arrangements without any chemical modifications. We synthesized disulfonic acid composed of a [1]benzothieno[3,2-b][1]benzothiophene (BTBT) moiety, and prepared organic salts with four butylamine isomers. Regardless of the type of butylamine combined, electronic states of the constituent BTBT derivative were identical, and all BTBT arrangements were edge-to-face herringbone-type. However, depending on the difference of steric hindrance, center-to-center distances and dihedral angles between neighboring BTBT moieties slightly varied. Despite a similar arrangement, the photoconductivity of four organic salts differed by a factor of approximately two. Additionally, theoretical charge carrier mobilities from their crystal structures exhibited a strong correlation with their photoconductivity.

Incidence of Blepharoptosis After Pars Plana Baerveldt 350 Glaucoma Implant Surgery by a Single Surgeon.

PURPOSE: To investigate the incidence of postoperative blepharoptosis and clinical risk factors for blepharoptosis after pars plana Baerveldt 350 glaucoma implantation (BGI) by a single surgeon for refractory glaucoma. METHODS: Twenty-four patients (30 eyes) who underwent pars plana BGI for refractory glaucoma at Toyama University Hospital between November 2019 and February 2021 were included. Patients with a preoperative margin reflex distance-1 (MRD-1) of ≥2 mm were included in the study, and a decrease in MRD-1 of ≥2 mm at 6 months postoperatively was defined as blepharoptosis. RESULTS: The mean MRD-1 decreased significantly from 3.2 ± 0.6 mm preoperatively to 2.4 ± 1.1 postoperatively ( p < 0.01). Postoperative ptosis developed in 8 eyes (26.7%). A comparison of the ptosis (n = 8) and nonptosis (n = 22) groups showed a significant difference in the history and number of previous filtration surgeries ( p = 0.02 and p = 0.03, respectively). Those with previous filtration surgery had a higher risk of blepharoptosis after pars plana BGI compared with those without previous filtration surgery (OR: 6.43; 95% confidence interval: 1.03-40.26; p = 0.04). CONCLUSION: Pars plana BGI is a risk factor for postoperative blepharoptosis. Particular attention should be paid to eyes that have undergone previous filtration surgery.

Identification and characterization of polydimethylsiloxane-binding peptides (PDMS-tag) for oriented immobilization of functional protein on a PDMS surface.

In this study we focused on identifying and characterizing polydimethylsiloxane-binding peptides (PDMS-tags) that show a strong binding affinity towards a PDMS surface. Three kinds of E. coli host proteins (ELN, OMC and TPA) that were preferentially adsorbed onto a PDMS surface were identified from the E. coli cell lysate via 2-D electrophoresis and MALDI TOF MS. Digestion of these PDMS-binding proteins by 3 types of proteases (trypsin, chymotrypsin and V8 protease) resulted in the production of a wide variety of peptide fragments with different amino acid biases. Nine types of peptide fragments showing binding affinities to a PDMS surface were identified, and they were genetically fused at the C-terminal region of glutathione S-transferase (GST). The adsorption kinetics of peptide-fused GSTs to a PDMS surface were evaluated using a quartz crystal microbalance (QCM) sensor equipped with a sensor chip coated with a PDMS thin film. Consequently, all GSTs fused with the peptides adsorbed at a level higher than that of wild-type GST. In particular, the adsorption levels of GSTs fused with ELN-V81, TPA-V81, and OMC-V81 peptides were 8- to 10-fold higher than that of the wild-type GST. These results indicated that the selected peptides possessed a strong binding affinity towards a PDMS surface even in cases where they were introduced to the C-terminal region of a model protein. The remaining activities of GSTs with PDMS-binding peptides were also greater than that of the wild-type GST. Almost a third (30%) of enzymatic activity was maintained by genetic fusion of the peptide ELN-V81, compared with only 1.5% of wild-type GST in the adsorption state. Thus, the PDMS-binding peptides (PDMS-tags) identified in this study will be considerably useful for the site-specific immobilization of functional proteins to a PDMS surface, which will be a powerful tool in the fabrication of protein-based micro-reactors and biosearation chips.