Micelle-based fluorogenic sensing of trypsin: a sensitive method in pancreatic disease diagnosis.

Protamine-mediated micellar aggregates, featuring an AIE-based fluorescent sensor, facilitate efficient detection of trypsin activity. This method enables the detection of trypsin at exceptionally low concentrations (0.01-0.1 µg mL-1) in urine, demonstrating its potential for early clinical diagnosis of trypsin-related pancreatic diseases.

Synthesis mechanism from graphene quantum dots to carbon nanotubes by ion-sputtering assisted chemical vapor deposition.

We present the first work of the synthesis mechanism from graphene quantum dots (GQDs) to carbon nanotubes (CNTs) by an ion-sputtering assisted chemical vapor deposition. During the annealing process, a Pt thin film deposited by the ion-sputtering was dewetted and agglomerated to form many nanometer-sized particles, leading to Pt nanoparticles (PtNPs) that can act as catalysts for creating carbon allotropes. The shape of the allotropes can be effectively tailored from GQDs to CNTs by controlling three key parameters such as the dose of catalytic ions (D), amounts of carbon source (S), and thermal energy (T). In our work, it was clearly proved that the growth control from GQDs to CNTs has a comparably proportional relationship with D and S, but has a reverse proportional relationship with T. Furthermore, high-purity GQDs without any other by-products and the CNTs with the cap of PtNPs were generated. Their shapes were appropriately controlled, respectively, based on the established synthesis mechanism.

Ultrasensitive Determination of Trypsin in Human Urine Based on Amplified Fluorescence Response.

The determination of trypsin activity in human urine is important for evaluating pancreatic disease. We designed an effective fluorescence sensing strategy based on a self-assembled amphiphilic pyrene/protamine complex system that provides an amplified fluorescence response for highly sensitive and selective detection of trypsin. In aqueous solution, the functionalized pyrene formed fluorescent, π-extended aggregates inside micelles, which were effectively quenched by protamine (a trypsin substrate). However, this quenched fluorescence was very sensitively recovered by the trypsin's enzymatic reaction, and this was attributed to a marked reduction in enhanced exciton migration caused by protamine in π-delocalized pyrene aggregates. The devised sensing platform was successfully utilized to selectively and sensitively detect trypsin at very low concentrations (0.03-0.5 µg mL-1) in non-pretreated human urine and to screen for trypsin inhibitors at concentrations of 0.1-5.0 µg mL-1.

Flexible Organic Photodetectors with Mechanically Robust Zinc Oxide Nanoparticle Thin Films.

Zinc oxide nanoparticle (ZnO-NP) thin films have been intensively used as electron transport layers (ETLs) in organic optoelectronic devices, but their moderate mechanical flexibility hinders their application to flexible electronic devices. This study reveals that the multivalent interaction between ZnO-NPs and multicharged conjugated electrolytes, such as diphenylfluorene pyridinium bromide derivative (DFPBr-6), can significantly improve the mechanical flexibility of ZnO-NP thin films. Intermixing ZnO-NPs and DFPBr-6 facilitates the coordination between bromide anions (from the DFPBr-6) and zinc cations on ZnO-NP surfaces, forming Zn2+-Br- bonds. Different from a conventional electrolyte (e.g., KBr), DFPBr-6 with six pyridinium ionic side chains holds the Br--chelated ZnO-NPs adjacent to DFP+ through Zn2+-Br--N+ bonds. Consequently, ZnO-NP:DFPBr-6 thin films exhibit improved mechanical flexibility with a critical bending radius as low as 1.5 mm under tensile bending conditions. Flexible organic photodetectors with ZnO-NP:DFPBr-6 thin films as ETLs demonstrate reliable device performances with high R (0.34 A/W) and D* (3.03 × 1012 Jones) even after 1000 times repetitive bending at a bending radius of 4.0 mm, whereas devices with ZnO-NP and ZnO-NP:KBr ETLs yield >85% reduction in R and D* under the same bending condition.

Protic Ionic Liquids for Intrinsically Stretchable Conductive Polymers.

Inspired by the classic hard-soft acid-base theory and intrigued by a theoretical prediction of spontaneous ion exchange between poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and hard-cation-soft-anion ionic liquid (IL), we treat PEDOT:PSS with a new IL composed of a protic (i.e., extremely hard) cation (3-methylimidazolium, p-MIM+) and an extremely soft anion (tetracyanoborate, TCB-). In fact, this protic IL (p-MIM:TCB) accomplishes the same levels of ion-exchange-mediated PEDOT-PSS separation, PEDOT-rich nanofibril formation, and electrical conductivity enhancement (∼2500 S/cm) as its aprotic counterpart (EMIM:TCB with 1-ethyl-3-methylimidazolium), the best IL used for this purpose so far. Furthermore, p-MIM:TCB significantly outperforms EMIM:TCB in terms of improving the stretchability (i.e., the highest tensile strain) of the PEDOT:PSS thin film. This enhancement is a result of the aromatic and protic cation p-MIM+, which acts as a molecular adhesive holding the exchanged ion pairs (PEDOT+:TCB----p-MIM+:PSS-) via ionic intercalation (at the surface of TCB--decorated PEDOT+ clusters) and hydrogen bonding (to PSS-), in which washing p-MIM+ out of the film degrades the stretchability while keeping the morphology. Our results offer molecular-level insight into the morphological, electrical, and mechanical properties of PEDOT:PSS and a molecular-interaction-based enhancement strategy that can be used for intrinsically stretchable conductive polymers.

Efficient Imidazolium-Biomolecule Interaction-Assisted Amplified Quenching for Ultrasensitive Detection of Heparin.

Detection of heparin (HP) under physiological conditions is difficult due to the presence of biological obstructions including proteins and lipids. Thus, it is highly challenging to selectively detect HP and to increase its sensitivity in complex systems. Here, we report the detection of HP at nanomolar levels via efficient imidazolium-HP interaction-assisted fluorescence quenching amplification. The self-assembled pyrenyl aggregates are devised as a conduit for efficient exciton transport, which induces amplified fluorescence quenching for HP detection. This amplified quenching is enhanced by introducing an imidazolium receptor designed to have a high affinity to HP via electrostatic and/or additional interactions with C2 protons, resulting in a very high Stern-Volmer quenching constant of approximately 1.17×108  M-1 .

Effect of Bulky Atom Substitution on Backbone Coplanarity and Electrical Properties of Cyclopentadithiophene-Based Semiconducting Polymers.

The effect of atomic substitution on the optoelectronic properties of a coplanar donor-acceptor (D-A) semiconducting polymer (SPs), prepared using cyclopentadithiophene (CDT) and 2,1,3-benzothiadiazole (BT) moieties, is investigated. By substituting a carbon atom in the BT unit with CF or C-Cl, two random D-A SPs are prepared, and their optoelectronic properties are thoroughly investigated. Density functional theory calculations demonstrate that the fluorinated polymer has a slightly smaller dihedral angle (Ï´ = 0.6°) than the pristine polymer (Ï´ = 1.9°) in its lowest-energy conformation, implying efficient charge transport through the coplanar backbone of the fluorinated polymer. However, the chlorinated polymer shows the lowest energy at a relatively larger dihedral angle (Ï´ = 139°) due to the steric hindrance induced by bulky chlorine atoms in the backbone, thereby leading to thin-film morphology, which is unfavorable for charge transport. Consequently, the fluorinated polymer yields the highest field-effect mobility (µ) of 0.57 cm2 V-1 s-1 , slightly higher than that of the pristine polymer (µ = 0.33 cm2 V-1 s-1 ), and the extended device lifetime of organic field-effect transistors over 12 d without any encapsulation layers. The results of this study provide design guidelines for air-stable D-A SPs.

Micellization-induced amplified fluorescence response for highly sensitive detection of heparin in serum.

Fluorescence-based assays should be feasible in aqueous media for effectively detecting the biological factors. However, numerous sensors have limited signal transductions and low fluorescence quantum yields due to the ingerently reduced excited state energy of fluorophores in aqueous solution, which reduces their sensitivity. This necessitates a smart sensing approach with an amplified fluorescence response for analytes in aqueous solution. Herein, a new building block which self-assembles in aqueous media, giving a micellar sturcuture with the hydrophobic π-extended conjugated system at the core and hydrophilic groups at the periphery, was devised for the first time. We demonstrated that the aggregated fluorophores in a micelle induce amplified fluorescence quenching, in which the excited electron efficiently migrates through π-extended conjugated system in a micelle, as in a polymeric system. Such feature differentiates this sensing approach from the numerous fluorescence-based tools previously developed for sensitive detection. This new system exhibited highly sensitive signal transduction for specific analytes even under actual bioanalytical conditions.

A micellized fluorescence sensor based on amplified quenching for highly sensitive detection of non-transferrin-bound iron in serum.

A novel, micelle-based fluorescence system capable of selective and sensitive signal transduction for non-transferrin-bound iron (NTBI) in serum was devised. We demonstrated that an aggregated fluorogenic core in a micelle induces amplified fluorescence quenching, which differentiates this sensing platform from the numerous fluorescence-based tools previously developed for sensitive detection.

A ratiometric fluorescence sensor based on enzymatically activatable micellization of TPE derivatives for quantitative detection of alkaline phosphatase activity in serum.

A novel ratiometric fluorescence assay via enzymatically activatable micellization in aqueous solution was devised for quantitative detection of alkaline phosphatase (ALP) activity. We demonstrated that the dephosphorylation of the water-soluble, phosphate-functionalized, fluorophore monomer P-TPE-TG, induced by an enzymatic reaction of ALP, leads to micelle formation in aqueous solution because its water-soluble functionality is reduced. The dephosphorylation-induced micellization of P-TPE-TG exhibited a ratiometric sensing response for various ALP concentrations (10-200 mU mL-1) and provided a suitable sensing platform for naked eye detection with increased fluorescence quantum yield (Φ = 3.2%), even compared to a typical TPE-based sensor (Φ = 1.0%), where ALP can be sensed with a detection limit of 0.034 mU mL-1. In addition, P-TPE-TG displayed excellent sensing performance at concentrations from 0 to 50 mU mL-1 in diluted human serum (10%), which offers the capability to exploit ratiometric responses for bioactive substances under practical conditions.

Clinical Effectiveness of Submucosal Injection with Indigo Carmine Mixed Solution for Colon Endoscopic Mucosal Resection.

BACKGROUND/AIMS: Submucosal injection with indigo carmine mixed solution can improve the delineation of colorectal neoplasia during endoscopic mucosal resection (EMR). Thus, the aim of this study was to evaluate the efficacy of submucosal injection with indigo carmine mixed solution during EMR of colorectal neoplasia. METHODS: This was a prospective, randomized, controlled study of a total of 212 neoplastic colon polyps (5-20 mm) subjected to EMR in a single tertiary university hospital. The patients were randomized into two groups according to whether or not indigo carmine mixed solution was used, and the complete resection rate (CRR) after EMR was evaluated. RESULTS: A total of 212 neoplastic polyps (normal saline group, 115; indigo carmine group, 97) were successfully removed by EMR. There was no significant difference in the CRR (92.8 vs. 89.6%, p = 0.414) or macroscopic delineation (86.0 vs. 93.8%, p = 0.118) between the two groups. In a separate analysis of sessile serrated adenomas/polyps (SSAs/Ps), macroscopic delineation was better in the indigo carmine group than the normal saline group (87.5 vs. 53.8%), albeit not significantly (p = 0.103). In univariate analyses, the CRR was significantly related to polyp location, polyp morphology, macroscopic delineation, and pathologic findings. In a multiple logistic regression analysis, macroscopic delineation (odds ratio (OR), 7.616, p = 0.001) and polyp pathology (OR, 8.621; p < 0.001) were significantly associated with the CRR. CONCLUSIONS: Submucosal injection with indigo carmine mixed solution did not improve the CRR or macroscopic delineation of EMR of colorectal neoplasias.

Controlling Molecular Ordering in Aqueous Conducting Polymers Using Ionic Liquids.

The molecular ordering of aqueous conducting polymers is controlled using a rational method. By introducing various ionic liquids, which have designed electrostatic interactions to PEDOT:PSS solutions, the evolution of the molecular ordering of the PEDOT is manipulated. Consequently, highly ordered nanostructures are achieved with a reduced π-π stacking distance of ≈3.38 Å and, thus, a maximum σdc of ≈2100 S cm-1 .

Ampullary neuroendocrine tumor diagnosed by endoscopic papillectomy in previously confirmed ampullary adenoma.

Ampullary adenoma is a common indication for endoscopic papillectomy. Ampullary neuroendocrine tumor (NET) is a rare disease for which complete surgical resection is the treatment of choice. However, because of the morbidity and mortality associated with surgical resection, endoscopic papillectomy is increasingly used in selected cases of low grade, with no metastasis and no invasion of the pancreatic or bile duct. Also, confirmed and complete endoscopic resection of ampullary NET accompanied by adenoma has not been reported to date. We report herein a rare case of an ampullary NET accompanied with adenoma, which was successfully and completely resected via endoscopic papillectomy. Prior to papillectomy, this case was diagnosed as an ampullary adenoma.

Long-Term Stable Recombination Layer for Tandem Polymer Solar Cells Using Self-Doped Conducting Polymers.

Recently, the most efficient tandem polymer solar cells (PSCs) have used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PEDOT: PSS) as a p-type component of recombination layer (RL). However, its undesirable acidic nature, originating from insulating PSS, of PEDOT: PSS drastically reduces the lifetime of PSCs. Here, we demonstrate the efficient and stable tandem PSCs by introducing acid-free self-doped conducting polymer (SCP), combined with zinc oxide nanoparticles (ZnO NPs), as RL for PEDOT: PSS-free tandem PSCs. Moreover, we introduce an innovative and versatile nanocomposite system containing photoactive and p-type conjugated polyelectrolyte (p-CPE) into the tandem fabrication of an ideal self-organized recombination layer. In our new RL, highly conductive SCP facilitates charge transport and recombination process, and p-CPE helps to achieve nearly loss-free charge collection by increasing effective work function of indium tin oxide (ITO) and SCP. Because of the synergistic effect of extremely low electrical resistance, ohmic contact, and pH neutrality, tandem devices with our novel RL performed well, exhibiting a high power conversion efficiency of 10.2% and a prolonged lifetime. These findings provide a new insight for strategic design of RLs using SCPs to achieve efficient and stable tandem PSCs and enable us to review and extend the usefulness of SCPs in various electronics research fields.

Highly conductive all-plastic electrodes fabricated using a novel chemically controlled transfer-printing method.

A novel transfer-printing method for high-performance all-plastic transparent electrodes is demonstrated. A solution process using H2 SO4 not only dramatically enhances the electrical conductivity of poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) over 4000 S cm(-1) but also chemically modifies its adhesion properties, thereby enabling expeditious "pick-and-place" transfer onto arbitrary surfaces using elastomeric stamps. Flexible and transparent optoelectronic devices with transferred PEDOT:PSS electrodes show superb performances.

Risk of malignancy in thyroid incidentalomas identified by fluorodeoxyglucose-positron emission tomography.

BACKGROUND: Thyroid incidentalomas detected by 2-deoxy-2-18F-fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) have been reported in 1% to 4% of the population, with a risk of malignancy of 27.8% to 74%. We performed a retrospective review of FDG-avid thyroid incidentalomas in cancer screening subjects and patients with nonthyroid cancer. The risk of malignancy in thyroid incidentaloma and its association with the maximal standardized uptake value (SUVmax) in 18F-FDG PET/CT were evaluated to define the predictor variables in assessing risk of malignancy. METHODS: A total of 2,584 subjects underwent 18F-FDG PET/CT for metastatic evaluation or cancer screening from January 2005 to January 2010. Among them, 36 subjects with FDG-avid thyroid incidentalomas underwent further diagnostic evaluation (thyroid ultrasonography-guided fine needle aspiration cytology [FNAC] or surgical resection). We retrospectively reviewed the database of these subjects. RESULTS: Of the 2,584 subjects who underwent 18F-FDG PET/CT (319 for cancer screening and 2,265 for metastatic evaluation), 52 (2.0%) were identified as having FDG-avid thyroid incidentaloma and cytologic diagnosis was obtained by FNAC in 36 subjects. Of the subjects, 15 were proven to have malignant disease: 13 by FNAC and two by surgical resection. The positive predictive value of malignancy in FDG-avid thyroid incidentaloma was 41.7%. Median SUVmax was higher in malignancy than in benign lesions (4.7 [interquartile range (IQR), 3.4 to 6.0] vs. 2.8 [IQR, 2.6 to 4.0], P=0.001). CONCLUSION: Thyroid incidentalomas found on 18F-FDG PET/CT have a high risk of malignancy, with a positive predictive value of 41.7%. FDG-avid thyroid incidentalomas with higher SUVmax tended to be malignant.

Long-term stable polymer solar cells with significantly reduced burn-in loss.

The inferior long-term stability of polymer-based solar cells needs to be overcome for their commercialization to be viable. In particular, an abrupt decrease in performance during initial device operation, the so-called 'burn-in' loss, has been a major contributor to the short lifetime of polymer solar cells, fundamentally impeding polymer-based photovoltaic technology. In this study, we demonstrate polymer solar cells with significantly improved lifetime, in which an initial burn-in loss is substantially reduced. By isolating trap-embedded components from pristine photoactive polymers based on the unimodality of molecular weight distributions, we are able to selectively extract a trap-free, high-molecular-weight component. The resulting polymer component exhibits enhanced power conversion efficiency and long-term stability without abrupt initial burn-in degradation. Our discovery suggests a promising possibility for commercial viability of polymer-based photovoltaics towards real solar cell applications.

Template-mediated nano-crystallite networks in semiconducting polymers.

Unlike typical inorganic semiconductors with a crystal structure, the charge dynamics of π-conjugated polymers (π-CPs) are severely limited by the presence of amorphous portions between the ordered crystalline regions. Thus, the formation of interconnected pathways along crystallites of π-CPs is desired to ensure highly efficient charge transport in printable electronics. Here we report the formation of nano-crystallite networks in π-CP films by employing novel template-mediated crystallization (TMC) via polaron formation and electrostatic interaction. The lateral and vertical charge transport of TMC-treated films increased by two orders of magnitude compared with pristine π-CPs. In particular, because of the unprecedented room temperature and solution-processing advantages of our TMC method, we achieve a field-effect mobility of 0.25 cm(2) V(-1) s(-1) using a plastic substrate, which corresponds to the highest value reported thus far. Because our findings can be applied to various π-conjugated semiconductors, our approach is universal and is expected to yield high-performance printable electronics.

A triple approach for diagnostic assessment of endoscopic ultrasound-guided fine needle aspiration in pancreatic solid masses and lymph nodes.

BACKGROUND AND AIMS: Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been becoming the standard tool for acquiring pancreatic lesion tissue. However, a single cytologic or histologic evaluation is not satisfactory for diagnosis. In this study, we evaluated the diagnostic yield of EUS-FNA for pancreatic solid masses and intra-abdominal lymph nodes using a triple approach. METHODS: This study included patients undergoing evaluation for a solid pancreatic mass (n = 59) or intra-abdominal lymph nodes (n = 16) using EUS-FNA with a 22- or 25-gauge (G) needle, respectively. The specimens from each pass were analyzed by on-site cytology using Diff-Quick stain, cytology using Papanicolaou stain, and histology with immunohistochemical (IHC) staining. RESULTS: A total of 75 patients (49 males; mean age; 63.7 years) were included. The median number of needle pass for diagnosis of malignancy was 2.0, and there was no technical failure. The diagnostic accuracies with on-site cytology, cytology using Papanicolaou staining, and histology were 70.7, 80.0, and 80.0 %, respectively. The diagnostic accuracy using a triple approach was significantly greater than cytology using Papanicolaou staining alone (94.7 vs. 80.0 %; p = 0.007). In patients with malignant lesions, cytology identified 12 of 71 (16.9 %) malignant lesions that were not diagnosed by histology using IHC, and histology identified six (8.5 %) malignant lesions that were not diagnosed by cytology. CONCLUSION: On-site cytopathologic evaluation combined with cytologic and histologic analysis with IHC stain for one-pass specimen is considered to be able to increase the overall accuracy of EUS-FNA in pancreatic solid masses and lymph nodes.