Resistive Pulse Sensing on a Capillary-Assisted Microfluidic Platform for On-Site Single-Particle Analyses

Capillary-assisted flow is valuable for utilizing microfluidics-based electrical sensing platforms at on-site locations by simplifying microfluidic operations and system construction; however, incorporating capillary-assisted flow in platforms requires easy microfluidic modification and stability over time for capillary-assisted flow generation and sensing performance. Herein, we report a capillary-assisted microfluidics-based electrical sensing platform using a one-step modification of polydimethylsiloxane (PDMS) with polyethylene glycol (PEG). As a model of electrical sensing platforms, this work focused on resistive pulse sensing (RPS) using a micropore in a microfluidic chip for label-free electrical detection of single analytes, and filling the micropore with an electrolyte is the first step to perform this RPS. The PEG-PDMS surfaces remained hydrophilic after ambient storage for 30 d and assisted in generating an electrolyte flow for filling the micropore with the electrolyte. We demonstrated the successful detection and size analysis of micrometer particles and bacterial cells based on RPS using the microfluidic chip stored in a dry state for 30 d. Combining this capillary-assisted microfluidic platform with a portable RPS system makes on-site detection and analysis of single pathogens possible.

Identifying high-grade serous ovarian carcinoma-specific extracellular vesicles by polyketone-coated nanowires

Cancer cell-derived extracellular vesicles (EVs) have unique protein profiles, making them promising targets as disease biomarkers. High-grade serous ovarian carcinoma (HGSOC) is the deadly subtype of epithelial ovarian cancer, and we aimed to identify HGSOC-specific membrane proteins. Small EVs (sEVs) and medium/large EVs (m/lEVs) from cell lines or patient serum and ascites were analyzed by LC-MS/MS, revealing that both EV subtypes had unique proteomic characteristics. Multivalidation steps identified FRα, Claudin-3, and TACSTD2 as HGSOC-specific sEV proteins, but m/lEV-associated candidates were not identified. In addition, for using a simple-to-use microfluidic device for EV isolation, polyketone-coated nanowires (pNWs) were developed, which efficiently purify sEVs from biofluids. Multiplexed array assays of sEVs isolated by pNW showed specific detectability in cancer patients and predicted clinical status. In summary, the HGSOC-specific marker detection by pNW are a promising platform as clinical biomarkers, and these insights provide detailed proteomic aspects of diverse EVs in HGSOC patients.

Mutation detection of urinary cell-free DNA via catch-and-release isolation on nanowires for liquid biopsy

Cell-free DNA (cfDNA) and extracellular vesicles (EVs) are molecular biomarkers in liquid biopsies that can be applied for cancer detection, which are known to carry information on the necessary conditions for oncogenesis and cancer cell-specific activities after oncogenesis, respectively. Analyses for both cfDNA and EVs from the same body fluid can provide insights into screening and identifying the molecular subtypes of cancer; however, a major bottleneck is the lack of efficient and standardized techniques for the isolation of cfDNA and EVs from clinical specimens. Here, we achieved catch-and-release isolation by hydrogen bond-mediated binding of cfDNA in urine to zinc oxide (ZnO) nanowires, which also capture EVs by surface charge, and subsequently we identified genetic mutations in urinary cfDNA. The binding strength of hydrogen bonds between single-crystal ZnO nanowires and DNA was found to be equal to or larger than that of conventional hydrophobic interactions, suggesting the possibility of isolating trace amounts of cfDNA. Our results demonstrated that nanowire-based cancer screening assay can screen cancer and can identify the molecular subtypes of cancer in urine from brain tumor patients through EV analysis and cfDNA mutation analysis. We anticipate our method to be a starting point for more sophisticated diagnostic models of cancer screening and identification.

All-in-One Nanowire Assay System for Capture and Analysis of Extracellular Vesicles from an ex Vivo Brain Tumor Model

Extracellular vesicles (EVs) have promising potential as biomarkers for early cancer diagnosis. The EVs have been widely studied as biological cargo containing essential biological information not only from inside vesicles such as nucleic acids and proteins but also from outside vesicles such as membrane proteins and glycolipids. Although various methods have been developed to isolate EVs with high yields such as captures based on density, size, and immunoaffinity, different measurement systems are needed to analyze EVs after isolation, and a platform that enables all-in-one analysis of EVs from capture to detection in multiple samples is desired. Since a nanowire-based approach has shown an effective capability for capturing EVs via surface charge interaction compared to other conventional methods, here, we upgraded the conventional well plate assay to an all-in-one nanowire-integrated well plate assay system (i.e., a nanowire assay system) that enables charge-based EV capture and EV analysis of membrane proteins. We applied the nanowire assay system to analyze EVs from brain tumor organoids in which tumor environments, including vascular formations, were reconstructed, and we found that the membrane protein expression ratio of CD31/CD63 was 1.42-fold higher in the tumor organoid-derived EVs with a p-value less than 0.05. Furthermore, this ratio for urine samples from glioblastoma patients was 2.25-fold higher than that from noncancer subjects with a p-value less than 0.05 as well. Our results demonstrated that the conventional well plate method integrated with the nanowire-based EV capture approach allows users not only to capture EVs effectively but also to analyze them in one assay system. We anticipate that the all-in-one nanowire assay system will be a powerful tool for elucidating EV-mediated tumor-microenvironment crosstalk.

POS1423 CHARACTERISTICS OF CYTOMEGALOVIRUS-POSITIVE VERSUS NEGATIVE, AND CYTOMEGALOVIRUS-TREATED VERSUS UNTREATED PATIENTS DURING IMMUNOSUPPRESSIVE THERAPY FOR RHEUMATIC DISEASES

Background

Immunosuppressive treatment is a common cause of cytomegalovirus (CMV) reactivation.

Objectives

To elucidate the characteristics of CMV-positive and negative patients during the treatment for rheumatic diseases.

Methods

We retrospectively evaluated consecutive patients admitted to our department from January 2006 to October 2021 whose C7-HRP antigen were measured. We collected their age, sex, primary problem and its lesion, and test results within 3 months before C7-HRP measurement. We also investigated the use of immunosuppressants, and maximum and cumulative dose of administered prednisolone within 6 months before C7-HRP measurement. Maximum and cumulative dose of prednisolone contained methylprednisolone pulse, which was converted into prednisolone equivalent. We investigated the characteristics of CMV-positive and negative patients, and those of CMV-positive patients with or without anti-CMV drug use.

Results

Of a total of 472 patients, 85 were positive and 387 were negative for C7-HRP. The average age was 71.2 vs. 64.4 (p=0.0021). Their male-to-female ratio was 20/65 vs. 120/267 (p=0.0290). The following diseases were significantly common among CMV-positive patients: microscopic polyangiitis (21.2% vs. 3.9%, p<0.0001), adult-onset Still’s disease (7.1% vs. 1.3%, p=0.0002), and systemic sclerosis (4.7% vs. 2.1%, p=0.0273). Significantly common comorbidities of CMV-positive patients were interstitial lung disease (35.3% vs. 16.0%, p<0.0001), nephritis (23.5% vs. 11.6%, p=0.0005), peripheral nervous system disorders (11.8% vs. 5.7%, p=0.0070), alveolar hemorrhage (5.9% vs. 0.8%, p=0.0001), and peripheral circulatory disorders (4.7% vs. 1.6%, p=0.0111). Average neutrophil counts (7720 /μL vs. 6440 /μL, p=0.0001), serum creatinine (1.0 mg/dL vs. 0.9 mg/dL, p=0.0104), and hemoglobin A1c (6.3% vs. 5.7%, p=0.0030) were significantly higher among CMV-positive patients, whereas hemoglobin (10.1 g/dL vs. 11.1 g/dL, p<0.0001), lymphocyte counts (820 /μL vs. 1190 /μL, p<0.0001), platelet counts (233000 /μL vs. 259000 /μL, p<0.0001), and serum albumin (2.9 g/dL vs. 3.4 g/dL, p<0.0001) were lower. Higher maximum dose of prednisolone (534.9 mg/day vs. 135.5 mg/day, p<0.0001), intravenous cyclophosphamide (27.1% vs. 11.4%, p<0.0001), rituximab (9.4% vs. 2.1%, p<0.0001), azathioprine (23.5% vs. 14.2%, p=0.0053), cyclosporin (8.2% vs. 3.6%, p=0.0101) were significantly more often used among CMV-positive patients. Average cumulative dose of prednisolone was 3022.6 mg vs. 1408.7 mg (p<0.0001). We also performed multivariate analysis, including the patients’ age, sex, maximum and cumulative dose of prednisolone, and the use of intravenous cyclophosphamide, rituximab, azathioprine, and cyclosporin. Elderly (p=0.0006), female (p=0.0293), high cumulative dose of prednisolone (p=0.0155), and the use of cyclosporin (p=0.0479) were significantly associated with CMV-positivity. Anti-CMV drug was administered to 63.5% of CMV-positive patients. The average age was significantly higher in anti-CMV-drug-treated patients than untreated patients (73.7 vs. 67.1, p=0.0492). The CMV-treated patients had significantly higher neutrophil counts (8540 /μL vs. 6280 /μL, p<0.0001), erythrocyte sedimentation rate (57.6 mm/h vs. 40.5 mm/h, p<0.0001), and C-reactive protein (5.3 mg/dL vs. 2.6 mg/dL, p<0.0001) than the untreated patients while the other data such as complete blood counts and serum chemistry revealed no significant difference. Average maximum dose of prednisolone was significantly higher in CMV-treated patients (617.1 mg/day vs. 391.1 mg/day, p=0.0261) while average cumulative dose of prednisolone and the use of any other immunosuppressants revealed no significant difference.

Conclusion

Intense immunosuppression, especially with higher dose of glucocorticoids, seemed to be the major risk factor of CMV reactivation. These medications may often require anti-CMV therapy.

Disclosure of Interests

None declared

AB0298 THE RISK OF SULPHA ALLERGY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Sulpha drugs have been used such as sulfasalazine for the treatment of rheumatoid arthritis (RA), and trimethoprim-sulfamethoxazole (TMP-SMX) for the treatment or prevention of pneumocystis pneumonia. However, some patients with RA delay treatment because of allergy to sulpha drugs[1]. We reported that 16.7% of RA patients presented drug allergies[2]. It was not clear what is a risk factor for drug allergies in patients with RA.

Objectives

The aim of this study was to evaluate the clinical features with sulpha allergy in patients with RA.

Methods

We prospectively examined consecutive patients diagnosed with RA in our hospital from March 2021 to January 2022. The patients with RA met the EULAR/ACR 2010 criteria. We included patients with RA with other rheumatic diseases. A careful allergic history was obtained from patients with RA and physical examination performed.

The first analysis was performed on patient baseline laboratory data at diagnosis of patients with RA with or without sulpha allergy. Sulpha allergy (rash, angioedema and anaphylaxis after drug exposure) was allergy to sulfasalazine or TMP-SMX. The second analysis was performed on seven types of allergic reactions: (1) drug allergies other than sulpha drugs (rash, angioedema and anaphylaxis after drug exposure), (2) food allergy (rash, angioedema and anaphylaxis after foods exposure), (3) allergic contact dermatitis such as metals, and other cosmetics, (4) seasonal allergic rhinitis and/or conjunctivitis (AR and/or AC), and AR and/or AC associated with house dust, (5) asthma, and (6) atopic dermatitis.

Results

There were 513 patients with RA in our study. In the first analysis, 17 patients with sulpha allergy and 496 patients without sulpha drugs were enrolled (Table 1). The median ages (with supha allergy and without sulpha allergy) were 66.0 and 72.0 years old (p=0.40). Females were 82.3% and 77.0%(p=0.4). The median observation period was 97.0 and 69.0 months (p=0.20). Patients with other rheumatic diseases were 11.6 and 6.8% (p=0.34).

Table 1.

Characteristics of RA patients at diagnosis of RA

With sulpha allergy (n = 17)Without sulpha allergy (n = 496)PFemale83.4%76.9%0.77Age, year, y66.0 (56.0-78.5)72.0 (60.0-80.0)0.40Observation period, m97.0 (45.5-182.0)69.0 (31.0-123.8)0.20Patients with other rheumatic diseases11.8%6.8%0.34ANA-positive patients(>1:80)52.9%28.2%0.052Anti-SSA antibody-positive patients46.2%18.2%0.02RF-positive patients40.0%66.8%0.049

The RA patients with sulpha allergy had higher positivity rate of anti-nuclear antibody (ANA) (>1:80) (52.9%, 28.2%: p=0.052), higher positivity rate of anti–Sjögren’s-syndrome-related antigen A autoantibody (anti-SSA antibody) than those without sulpha allergies (46.2%, 18.2%: p = 0.02) and lower positivity rate of rheumatoid factor(RF) than those without sulpha allergies (40.0%, 66.8%: p = 0.049).

In the second analysis drug allergies other than sulpha allergy were more frequent in patients with sulpha allergy. Drug allergies other than sulpha allergy were such as antibiotics and nonsteroidal anti-inflammatory drugs. There were no significant differences in other allergies.

Conclusion

Among patients with RA, patients with sulpha allergy had higher positivity rate of ANA and anti-SSA antibody, and lower positivity rate of RF than those without sulpha allergy. RA patients with sulpha allergy had a higher prevalence of the other drug allergies than those other than sulpha allergy.

References

[1]Konishi MH et al. Allergic diseases in adult-onset Still’s disease and rheumatoid arthtitis. Arerugi. 2021; 70: 965-975.

[2]Konishi MH et al. Allergic Disorders and Drug Allergies in Primary Sjögren’s Syndrome and Rheumatoid Arthritis. EULAR 2021.

Disclosure of Interests

None declared

Patterns of nesting behaviour and nesting success for green turtles at Raine Island, Australia

To understand how turtles use the nesting habitat at Raine Island across a nesting season, and how the turtles respond to the restoration of the island’s dune systems, we identified 534 nesting events for 39 green turtles Chelonia mydas across 2 breeding seasons using data derived from satellite tags. Tracked turtles laid between 4 and 10 clutches of eggs. Patterns of nesting success varied between individuals, within and between seasons. Nesting success was higher in 2018-19 (57%) than 2017-18 (45%), and in both years, nesting success was lowest between October and early January (<50%). In 2017-18, increased rainfall in January corresponded with increased nesting success (>50%). The density of female turtles ashore was lower in 2018-19, and likely explains higher nesting success in 2018-19 because competition for nest space was lower. In 2017-18, females had more attempts per clutch, and the attempts were around 90 min longer. Consequently, energy required to lay a clutch of eggs in 2017-18 was significantly higher than in 2018-19, highlighting potential costs of lower nesting success rates on reproductive output. The area of beach re-profiled as an intervention in 2014 and 2017 was a nesting hotspot in 2017-18. However, in 2018-19, the area was not used to the same extent, and the nesting hotspot occurred on the north-eastern unaltered beach. Collectively, the tracking of turtles across the whole nesting season enabled us to assess overall beach use and nesting site fidelity of green turtles at Raine Island. Results will aid future planning and management of beach restoration activities at turtle nesting sites.

Pebbles and sand on asteroid (162173) Ryugu: In situ observation and particles returned to Earth

The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. The mission performed two landing operations to collect samples of surface and subsurface material, the latter exposed by an artificial impact. We present images of the second touchdown site, finding that ejecta from the impact crater was present at the sample location. Surface pebbles at both landing sites show morphological variations ranging from rugged to smooth, similar to Ryugu's boulders, and shapes from quasi-spherical to flattened. The samples were returned to Earth on 6 December 2020. We describe the morphology of >5 grams of returned pebbles and sand. Their diverse color, shape, and structure are consistent with the observed materials of Ryugu; we conclude that they are a representative sample of the asteroid.

Water-Selective Nanostructured Dehumidifiers for Molecular Sensing Spaces

Humidity and moisture effects, frequently called water poisoning, in surroundings are inevitable for various molecular sensing devices, strongly affecting their sensing characteristics. Here, we demonstrate a water-selective nanostructured dehumidifier composed of ZnO/TiO₂/CaCl₂ core-shell heterostructured nanowires for molecular sensing spaces. The fabricated nanostructured dehumidifier is highly water-selective without detrimental adsorptions of various volatile organic compound molecules and can be repeatedly operated. The thermally controllable and reversible dehydration process of CaCl₂·nH₂O thin nanolayers on hydrophilic ZnO/TiO₂ nanowire surfaces plays a vital role in such water-selective and repeatable dehumidifying operations. Furthermore, the limitation of detection for sensing acetone and nonanal molecules in the presence of moisture (relative humidity ∼ 90%) was improved more than 20 times using nanocomposite sensors by operating the developed nanostructured dehumidifier. Thus, the proposed water-selective nanostructured dehumidifier offers a rational strategy and platform to overcome water poisoning issues for various molecular and gas sensors.

Microheater-integrated zinc oxide nanowire microfluidic device for hybridization-based detection of target single-stranded DNA

Detection of cell-free DNA (cfDNA) has an impact on DNA analysis in liquid biopsies. However, current strategies to detect cfDNA have limitations that should be overcome, such as having low sensitivity and requiring much time and a specialized instrument. Thus, non-invasive and rapid detection tools are needed for disease prevention and early-stage treatment. Here we developed a device having a microheater integrated with zinc oxide nanowires (microheater-ZnO-NWs) to detect target single-stranded DNAs (ssDNAs) based on DNA probe hybridization. We confirmed experimentally that our device realizedin-situannealed DNA probes by which we subsequently detected target ssDNAs. We envision that this device can be utilized for fundamental studies related to nanobiodevice-based DNA detection.

Microfluidic-based capture and release of cancer-derived exosomes via peptide-nanowire hybrid interface

Cancer-derived circulating exosomes or nanoscale extracellular vesicles are emerging biomarkers for disease detection and treatment because of their cell-specific constituents and unique intercellular pathways. For efficient exosome isolation from bio-fluids, the design of high-affinity nanointerfaces is of great importance in the development of miniaturized systems for the collection of exosomes. Herein, we report peptide-functionalized nanowires as a biorecognition interface for the capture and release of cancer-derived exosomes within a microfluidic channel. Based on the amino-acid sequence of EWI-2 protein, a partial peptide that bound to the CD9 exosome marker and thus targeted cancer exosomes was screened. Linkage of the exosome-targeting peptide with a ZnO-binding sequence allowed one-step and reagent-free peptide modification of the ZnO nanowire array. As a result of peptide functionalization, the exosome-capturing ability of ZnO nanowires was significantly improved. Furthermore, the captured exosomes could be subsequently released from the nanowires under a neutral salt condition for downstream applications. This engineered surface that enhances the nanowires' efficiency in selective and controllable collection of cancer-derived exosomes provides an alternative foundation for developing microfluidic platforms for exosome-based diagnostics and therapeutics.

ZnO/SiO2 core/shell nanowires for capturing CpG rich single-stranded DNAs

Atomic layer deposition (ALD) is capable of providing an ultrathin layer on high-aspect ratio structures with good conformality and tunable film properties. In this research, we modified the surface of ZnO nanowires through ALD for the fabrication of a ZnO/SiO2 (core/shell) nanowire microfluidic device which we utilized for the capture of CpG-rich single-stranded DNAs (ssDNA). Structural changes of the nanowires while varying the number of ALD cycles were evaluated by statistical analysis and their relationship with the capture efficiency was investigated. We hypothesized that finding the optimum number of ALD cycles would be crucial to ensure adequate coating for successful tuning to the desired surface properties, besides promoting a sufficient trapping region with optimal spacing size for capturing the ssDNAs as the biomolecules traverse through the dispersed nanowires. Using the optimal condition, we achieved high capture efficiency of ssDNAs (86.7%) which showed good potential to be further extended for the analysis of CpG sites in cancer-related genes. This finding is beneficial to the future design of core/shell nanowires for capturing ssDNAs in biomedical applications.

Oxide Nanowire Microfluidic Devices for Capturing Single-stranded DNAs

Since DNA analysis is the fundamental process for most applications in biomedical fields, capturing DNAs with high efficiency is important. Here, we used several oxide nanowire microfluidic devices to capture CpG-rich single-stranded DNAs (ssDNAs) in different pH solutions. All the oxide nanowires exhibited the highest capture efficiency around pH 7 with good capture efficiency shown by each metal oxide; ZnO/ZnO core/shell NWs (71.6%), ZnO/Al₂O₃ core/shell NWs (86.3%) and ZnO/SiO₂ core/shell NWs (86.7%). ZnO/Al₂O₃ core/shell NWs showed the best performance for capturing ssDNAs under varying pH, which suggests its suitability for application in diverse biological fluids. The capturing efficiencies were attributed to the interactions from phosphate backbones and nucleobases of ssDNAs to each nanowire surface. This finding provides a useful platform for highly efficient capture of the target ssDNAs, and these results can be extended for future studies of cancer-related genes in complex biological fluids.

Early restenosis and late catch-up phenomenon after newer biodegradable- and durable-polymer drug-eluting stent implantations

Background

It is yet to be known whether mechanisms underlying restenosis in newer-generation durable-polymer (DP) and biodegradable-polymer (BP) drug-eluting stents (DES) are different.

Purpose

This study aims to assess the incidences and predictors of early restenosis and late catch-up phenomenon after newer-generation durable-polymer (DP) and biodegradable-polymer (BP) DES.

Methods

Between 2010 and 2017, 13858 lesions in 6350 patients were treated with DES (4393 BP-DES, 9465 DP-DES). The early-term (within 1 year) and late-term (from 1 to 2 years) follow-up angiographies were scheduled. Late catch-up phenomenon was defined as in-stent restenosis (ISR) in lesions that evaded ISR within 1 year after stent implantation. ISR was defined as angiographic restenosis of more than 50%.

Results

The mean patient age was 71 years, and 76.7% were male. Early-term angiographies were performed in 10955 lesions (79.0%). Of those without early-term ISR, late-term angiographies were performed in 7771 lesions (56.1%). The incidences of mid-term restenosis and late catch-up phenomenon were 6.6% and 3.9%, respectively.

In the multivariate regression analyses, history of diabetes, hemodialysis and previous PCI were independent predictors of both early restenosis and late catch-up phenomenon. Also, some lesion characteristics such as chronic total occlusion, right coronary artery ostial lesion, small vessel (defined as reference diameter &lt;2.5mm), long lesion (defined as lesion length &gt;30mm) and treatment of ISR lesion were independent predictors of both early restenosis and late catch-up phenomenon.

Bifurcation lesion and heavily calcified lesion treated with rotablator were independent risk of early restenosis. Bypass graft lesion was an independent predictor of late catch-up phenomenon.

Early restenosis was observed less frequently in DP-DES than in BP-DES (6.3% versus 7.4%, P=0.012). On the contrary, late catch-up phenomenon was observed more frequently in DP-DES than in BP-DES (4.3% versus 2.9%, P=0.026).

Conclusions

Some lesion characteristics were independent predictors of early restenosis and late catch-up phenomenon after newer-generation DES implantation. The deployment of BP-DES resulted in more early restenosis and less late catch-up phenomenon compared to that of DP-DES.

Early Restenosis and Late Catch-Up

Funding Acknowledgement

Type of funding source: None

Clinical features and prognosis of acute myocardial infarction due to coronary artery embolism

Background

Coronary artery embolism (CE) is one of the important causes of acute coronary syndrome (ACS). The feature of CE is that angiographic evidence of coronary artery embolism and thrombosis without atherosclerotic components. However, the prevalence of CE remains unknown because of the diffifulty to diagnose in the acute settings. A recent retrospective analysis suggested that up to 3% of ACS cases may result from CE.

Purpose

The aim of this study was to elucidate the prevalence, clinical features and long-term outcomes including all-cause and cardiac death.

Methods

We analysed the consecutive 2695 patients with first AMI performed coronary intervention between January 2004 and July 2017. CE was diagnosed by clinical histories and angiographic findings. We retrospectively evaluated the clinical and lesion characteristics and outcomes including all-cause and cardiac death.

Results

The prevalence of CE was 2.0% (n=55; CE group and n=2640; non-CE group), including 8 (15%) patients with multivessel CE. The CE group had higher average age (70.8±14.9 vs. 68.4±12.6, p&lt;0.01), prevalence of female (54% vs. 27%, p&lt;0.01), lower prevalence of smoking (34% vs. 62%, p&lt;0.01). The common causes with CE were atrial fibrillation (47%), and malignant tumor (9%), and cardiomyopathy (5%), and patent foramen ovale (4%). Only 20% of patients with CE were treated with anti-coagulant therapy. The rate of distal infarction site (defined as #4, #8, #14–15) was significantly higher in CE group than non-CE group (54.0% vs. 4.9%, p&lt;0.01). During median follow-up of 53.6 [32.6–77.3] months, CE and thromboembolism recurred in 5 patients (CE: 1 patient, stroke 4 patients). The 4-year incidence of all-cause death was significantly higher in the CE group, but cardiac death was not significantly different between the groups (28.8% vs. 14.8%, p=0.03; 12.8% vs. 5.1%, p=0.11).

Conclusion

Compared with non-CE group, the prevalence of distal infarction site was significantly higher in the CE group, and the incidence of cardiac death is not significantly different.

Funding Acknowledgement

Type of funding source: None

Risk stratification based on academic research consortium high bleeding risk criteria for long-term bleeding event after everolimus-eluting stent implantation

Background

Recently, the Academic Research Consortium for High Bleeding Risk (ARC-HBR) criteria has been suggested as the standard definition of HBR.

Purpose

We aimed to investigate the risk stratification based on ARC-HBR Criteria for long-term bleeding event after everolimus-eluting stent implantation

Methods

The study population comprised 1193 patients treated with EES without in-hospital event between 2010 and 2011. Individual ARC-HBR criteria was retrospectively assessed. Major bleeding were defined as the occurrence of a Bleeding Academic Research Consortium type 3 or 5 bleeding event. The mean follow-up period was 2996±433 days.

Results

There were 656 patients (55.0%) in HBR-groups. Cumulative incidence of major bleeding was significantly higher in HBR-group (8.1% vs 3.4% at 4 year, and 16.2% vs 5.7% at 8 year, P&lt;0.001). Cumulative rate of major bleeding tend to be higher as the number of ARC-HBR criteria increased (≥2 Majors: 24.3%, 1 Major: 17.0%, ≥2 Minors:11.7%, and Non-HBR: 5.7%, P&lt;0.001).

Conclusion

ARC-HBR criteria successfully stratified the long-term bleeding risk after drug-eluting stent implantation in real-world practice.

Funding Acknowledgement

Type of funding source: None

Photolithographically Constructed Single ZnO Nanowire Device and Its Ultraviolet Photoresponse

A sparse ZnO nanowire array with aspect ratio of ca. 120 and growth rate of 1 μm/h was synthesized by controlling the density of seeds at the initial stage of nanowire growth. The spatially-separated nanowires were cut off from the growth substrate without breaking, and thus were useful in the construction of a single-nanowire device by photolithography. The device exhibited a linear current-voltage characteristic associated with ohmic contact between ZnO nanowire and electrodes. The device further demonstrated a reliable photoresponse with an IUV/Idark of ∼100 to ultraviolet light irradiation.

Mechanical Rupture-Based Antibacterial and Cell-Compatible ZnO/SiO2 Nanowire Structures Formed by Bottom-Up Approaches

There are growing interests in mechanical rupture-based antibacterial surfaces with nanostructures that have little toxicity to cells around the surfaces; however, current surfaces are fabricated via top-down nanotechnologies, which presents difficulties to apply for bio-surfaces with hierarchal three-dimensional structures. Herein, we developed ZnO/SiO2 nanowire structures by using bottom-up approaches and demonstrated to show mechanical rupture-based antibacterial activity and compatibility with human cells. When Escherichia coli were cultured on the surface for 24 h, over 99% of the bacteria were inactivated, while more than 80% of HeLa cells that were cultured on the surface for 24 h were still alive. This is the first demonstration of mechanical rupture-based bacterial rupture via the hydrothermally synthesized nanowire structures with antibacterial activity and cell compatibility.

An artificial impact on the asteroid (162173) Ryugu formed a crater in the gravity-dominated regime

The Hayabusa2 spacecraft investigated the small asteroid Ryugu, which has a rubble-pile structure. We describe an impact experiment on Ryugu using Hayabusa2's Small Carry-on Impactor. The impact produced an artificial crater with a diameter >10 meters, which has a semicircular shape, an elevated rim, and a central pit. Images of the impact and resulting ejecta were recorded by the Deployable CAMera 3 for >8 minutes, showing the growth of an ejecta curtain (the outer edge of the ejecta) and deposition of ejecta onto the surface. The ejecta curtain was asymmetric and heterogeneous and it never fully detached from the surface. The crater formed in the gravity-dominated regime; in other words, crater growth was limited by gravity not surface strength. We discuss implications for Ryugu's surface age.

P1307 An echocardiographic observation over the disappearing process of the prosthetic valve thrombus caused by the inflammatory hypercoagulability; a case report

Background

Whenever fever and inflammatory reaction continue for a while in the patients with a prosthetic valve, than usual, we must keep infective endocarditis in mind. On the other hand, inflammation and thrombosis are well known to coexist often. There are several reports of thrombotic valves associated with inflammation-activated hypercoagulability. Furthermore, C-reactive protein (CRP) has been reported to imply an increased risk of thrombus especially in the presence of an injury on the prosthetic valve.

Case report

We report a case of a 70-year-old male with a leaflet thrombus on the bioprosthetic aortic valve. He suffered from fever, and symptoms of heart failure and was hospitalized for treatment. Blood tests presented that white blood cell count was 4900/μL (neutrophil 81.1%) and CRP 10.82 mg/dL. Infectious endocarditis (IE) was suspected. Transthoracic echocardiography (TTE) was per-formed, however, vegetation and abscess were not found. Noteworthily, the bioprosthetic valve leaflet on the right coronary cusp showed thickening and opening dysfunction (Figure A, parasternal short axis). Mean pressure gradient (mPG) through the aortic valve was 15mmHg and peak velocity (Vmax) 2.7m/s. Blood culture was negative, and his body temperature and CRP were improved by empirical antibiotic administration. The anticoagulation therapy with warfarin was started, he was discharged from the hospital and followed up in the outpatient clinic. TTE after the initiation of anticoagulation therapy, did not reveal any more dysfunction on the bioprosthetic valve (mPG: 9mmHg, Vmax: 2.2m/s) (Figure B, parasternal short axis). The diagnostic and therapeutic process of this case implied success. The opening-dysfunction of prosthetic valve leaflets was reversible and therefore, we concluded that the thickening of the prosthetic valve could be attributed to thrombus adhesion. Computed Tomography (CT) was not performed because he suffered from chronic kidney disease.

Conclusion

Surely, CT is very useful for the evaluation of thrombotic valves in the patients in whom it is permissible to use contrast agent. However, we could successfully evaluate the recovery process of leaflet thrombosis by echocardiography because of a difficult reason of CT use in this case. The prolongation of inflammatory reaction in the patients with a prosthetic valve should keep IE in mind in everyday life. Even if the findings of bacterial infection are obscure, it is more and more important to observe carefully the change of leaflets, whenever an open-dysfunction and a thrombus adhesion of the prosthetic valves exist.

Abstract P1307 Figure.

P702 An unusual echocardiographic finding of protrusive vegetation caused by perivalvular abscess perforation into the left atrium

Background

It is well-known that Infective endocarditis (IE) caused by S. aureus progresses rapidly and is highly destructive. The most often abscess formation after aortic valve replacement (AVR) is the mitral-aortic intervalvular fibrosa (MAIVF). It is difficult to cure MAIVF radically once infection occurs, and then the abscess tends to spread. After abscess formation is once established, IE tends to be widespread, the prognosis is definitely poor unless surgical repairment is executed, and then an emergency surgery is essential and unavoidable for complete cure. We report an unusual case of aortic valve abscess with perforation of vegetation into the left atrium after aortic valve replacement.

Case report

A 77-year-old man underwent the bioprosthetic AVR for aortic valve stenosis one month ago. On the 9th day after discharge, he visited the hospital for the follow-up. At the time, the body temperature was 36.6 ° C, the blood pressure 133/50 mmHg, white blood cell count 10500/μL, and C-reactive protein 3.31 mg/dL. Transthoracic echocardiography (TTE) demonstrated the perivalvular abscesses on the prosthetic aortic valve and mass structures attached to the MAIVF in the left atrium (Figure A, C). He was hospitalized again and had an emergency re-operation. Intraoperative transesophageal echocardiography (TEE) showed a perivalvular abscess on the prosthetic valve, and a high-intensity structure (vegetation like) protruding from the Valsalva Sinus into the left atrium of the MAIVF (Figure B, D). Surgical findings did not reveal any wart on the native valve itself. One-third of the annulus was disrupted. The subvalvular tissue all around was abscessed. Notably, the abscess cavity between NCC and LCC reached MAIVF of the anterior mitral leaflet, and the structure projecting to the left atrium was vegetation. In this case, TTE pointed out a perivalvular abscess of the aortic valve, IE was suspected at the time of outpatient visit at an early stage after discharge, and the spread of inflammation was observed with a high speed beyond the expectation at the time of operation.

Conclusion

Early after the operation, TTE revealed a mass was protruded into the left atrium. Generally, vegetation is soft and flexible in itself. However, in this case, the vegetation was less mobile, and for that reason, abscesses or tumors were suspected. TEE enabled us to obtain anatomically more detailed information and to foresee the left atrial wall repairment at the time of reoperation. We reported an unusual case of IE with solid vegetation attached to the wall and difficult to diagnose.

Abstract P702 Figure.

P248 Changes of atrial septum defect caused by posture during three-dimensional transesophageal echocardiography ( a case of Platypnea-orthodeoxia syndrome)

Background

Platypnea-Orthodeoxia syndrome (POS) is a rare phenomenon which is characterized postural hypoxia due to the intracardiac shunt from right to left through a patent foramen ovale, an atrial septal defect or a pulmonary arteriovenous malformation. POS is often underestimated because the hypoxia by postural change is difficult to be detected. We evaluated three-dimensional transesophageal echocardiography (TEE) to diagnose POS in an elderly patient.

Case report

A 84-year-old woman suffered from repetitive syncope for several years. She undertook twelve leads electrocardiogram (ECG), screening transthoracic echocardiography (TTE), twenty-four hours ECG and treadmill stress ECG, however, the cause of syncope was not identified. After another syncope event happened, she was transferred to the emergency room. Then, the hypoxia caused by sitting position was pointed out for the first time.

Her hypoxia was improved by supine position and oxygen administration. TTE demonstrated no right heart enlargement. Shunt flow was suspected on her atrial septum; however, it was difficult to reveal it by TTE because of her obesity. Therefore, she underwent intravenous saline injection test. In the decubitus position, an intravenous injection of saline under Valsalva maneuver revealed the shunt flow from the right atrium to the left atrium. Her arterial oxygen saturation (SpO2) was 95%. In the sitting position, a visible shunt flow was observed, then her SpO2 dropped to 85%. By TEE, the shunt hole was found in the oval fossa of the atrial septum. TEE was evaluated by different positions. The atrial defect hole became larger in the sitting position (area 1.05cm2) than in the supine position (area 0.43cm2). As a result, the postural change to sitting revealed Platypnea-Orthodeoxia syndrome associated with ASD. The pulmonary blood flow/systemic blood flow ratio (Qp/Qs) was estimated at 1.6. After surgical ASD closure, she was discharged without any symptoms.

Conclusion

Unclearness of TTE and the absence of a right heart overload may lead to misdiagnosis of POS. If a syncope patient caused hypoxia in the only sitting position, detailed echocardiography should be needed to rule out a diagnosis of POS. This is considerably valuable case of three-dimensional TEE confirmed the changes of ASD size by postural change.

Abstract P248 Figure.

P1472 Concealed thrombus in a 12-year-old boy diagnosed by disappearance of intricate comb-like pectinate muscle form in the left atrial appendage

Background

As previously known, patients with prolonged atrial fibrillation often have atrial thrombus. However, in children, cardiogenic embolism due to atrial fibrillation is rare. Also, the diagnosis of residual thrombus in the left atrial appendage is sometimes difficult even by transesophageal echocardiography (TEE). We have obtained a meaningful comparison between TEE findings and surgical specimen of bilateral atrial appendage.

Case report

A 12-year-old boy admitted to the nearby hospital, because of sudden onset of right-side hemiplegia. Till then, he was born at normal weight and grew up without any problem. The electrocardiogram indicated atrial fibrillation. He was transferred to the pediatric cardiology department of a hospital with higher function for the treatment of cardiogenic thromboembolism.

After 72 hours from the onset of first thromboembolism, a new embolic event happened in his left brachial artery. The contrast-enhanced computed tomography (CT) showed thrombus of bilateral atrium and coronary sinus. Consequently, residual thrombus led to the potential risk of additional embolization. Therefore, catheter cerebral thrombectomy was performed, and then surgical thrombectomy for the bilateral atrium was planned. Preoperative CT showed thrombus in the left atrial appendage (LAA). However, intraoperative TEE showed no obvious thrombus in the LAA. Intricate pectinate muscle formation in the left atrial appendage almost disappeared (figure1A), which suspected remaining thrombus. In addition, massive thrombus was seen in the right atrium and coronary sinus. Coronary sinus thrombus was removed as far as possible, and bilateral atrial appendage resection and myocardial biopsy were performed. Simultaneously, modified-Maze was also done. Heart rhythm returned into sinus rhythm after surgery. Pathological findings did not show specific findings of myocarditis or pericarditis.

Until now, the cause of thrombotic factors has not been fully clarified. Although the time of onset is unknown, probably, heart failure was triggered by atrial fibrillation, and consequently thromboembolism occurred. In the resected left atrial appendage, small thrombus remained among pectinate muscle (figure1B); therefore, postoperative anticoagulation should be needed.

Conclusion

We experienced a boy with thrombus in bilateral atrial appendages. In the resected left atrial appendage, multiple small thrombi remained in the pectinate muscle. From our experience, the disappearance of comb-like form in pectinate muscle by TEE suspects the residual thrombus, especially in the case of cardiogenic embolism.

Abstract P1472 Figure.

P2693Late catch-up phenomenon and late-term target lesion revascularization of two-stenting for coronary bifurcation lesions between first and second generation drug-eluting stents

Background

The second generation drug-eluting stent (G2-DES) has been reported as superior to the first generation drug-eluting stent (G1-DES) in mid-term outcomes. However, the late-term outcomes between G1-DES and G2-DES in two-stenting for coronary bifurcation lesions are not well studied.

Purpose

To evaluate the late catch-up phenomenon and late-term target lesion revascularization (TLR) of two-stenting for coronary bifurcation lesions between G1-DES and G2-DES.

Methods

This study included 1133 lesions in 1089 patients undergoing drug eluting stent implantation with two stenting from 2004 to 2016. These consisted of 496 G1-DES implanted lesions and 637 G2-DES implanted lesions. Late-term follow-up angiography was performed without in-stent restenosis (ISR) and TLR at mid-term follow-up in 582 lesions (242 G1-DES lesions and 340 G2-DES lesions). ISR was defined as more than 50% restenosis. Late catch-up phenomenon was defined as ISR without ISR within 1 year following index stent implantation. Late-term TLR was defined as from 1 to 5 year TLR. Bifurcation lesions were defined as the main branch ranging from the proximal stem to the distal main branch with boundaries defined by 5 mm proximal and distal to the stent-implanted area, and the side branch ranging from the bifurcation carina to the distal side branch with boundaries defined by the carina and 5 mm distal to the stent-implanted area.

Results

The median follow-up duration was 5.1 years (the first and third quarters, 3.2 and 7.1 years). The late-catch up phenomenon rate significantly differed between the G1-DES and G2-DES groups (16.9% vs 8.4%, p=0.001). A significant difference in late catch-up between the same two groups was also observed in bifurcation lesions of the main branch (5.0% vs 0.6%, p=0.001) and side branch (10.3% vs 5.6%, p=0.033), respectively. The 5-year cumulative rates also differed between the two groups in TLR (8.2% vs 3.7% log-rank p=0.001), and late-term TLR (7.0% vs 3.6% log-rank p=0.001).

Conclusion

Two-stenting using G2-DES, compared with G1-DES, significantly reduced late-term restenosis and TLR. The restenosis rate in bifurcation area may be associated with differences between two groups in late-term outcome.

P5614The association between tissue morphology assessed with optical coherence tomography and mid and late-term results after percutaneous coronary intervention for in-stent restenosis lesions

Background

It was reported that tissue morphology of in-stent restenosis (ISR) lesions assessed with optical coherence tomography (OCT) had an effect on midterm results including ISR and target lesion revascularization (TLR) rates after percutaneous coronary intervention (PCI). However, little was known about the association between tissue morphology assessed with OCT and late-term results.

Methods

We performed PCI treated with paclitaxel coated balloon (PCB) or drug-eluting stent (DES) for 452 ISR lesions (260 lesions with fibrous plaque and 192 lesions with lipid-laden plaque) using OCT between May 2008 and July 2016. Six- to eight-month (midterm) angiographic follow-up was performed on 422 of the 452 ISR lesions (follow-up rate: 93.4%). Furthermore, eighteen- to twenty-month (late-term) angiographic follow-up was performed on 337 of the 361 ISR lesions (follow-up rate: 93.4%) which were free from midterm TLR. We examined the association between tissue morphology, midterm-results and late-term results including ISR and TLR rates. Fibrous plaque was defined as homogeneous, signal-rich regions with low attenuation. Lipid-laden plaque was defined as diffuse border, signal poor regions with high attenuation.

Results

The patients were 353 men and 69 women, and the mean age was 68.8±9.6 years. PCI were performed with PCB in 285 lesions (PCB group) and DES in 137 lesions (DES group). The figure shows the angiographic midterm results of the 422 lesions and late-term results of the 337 lesions with respect to each tissue morphology and each PCI device. There was no difference in ISR and TLR rates of lesions with both fibrous and lipid-laden plaque at midterm between the two groups. ISR and TLR rates of lesions with lipid-laden plaque at late-term were significantly higher in the PCB group than in the DES group, while there was no difference in ISR and TLR rates of lesions with fibrous plaque at late-term between two groups.

Figure 1

Conclusion

Tissue morphology of ISR lesions might have an impact on outcomes after PCI. Morphological assessment of ISR tissue using OCT might suggest favorable types of PCI for ISR lesions.

P1628Angiopoietin-like protein (Angptl) 2 secreted from epicardial adipose tissue induces atrial myocardial fibrosis

Background

Using excised human left atrial appendage samples, we previously demonstrated that epicardial adipose tissue (EAT) are highly associated with atrial myocardial fibrosis as a substrate of atrial fibrillation (AF). We also reported the relationship between Angptl2 in EAT and atrial fibrosis. However, the mechanism is not clear. The purpose is to clarify the mechanisms underlying the effect of EAT on the atrial myocardium.

Methods

Human peri-left atrial EAT and abdominal subcutaneous adipose tissue (SAT) samples were obtained from 6 cases (2 females, 70.2±13.2 years). 50 mg of EAT and SAT were quickly washed with PBS and centrifuged 1min at 1200rpm. After 3 times this procedures, adipose tissues were cultured in DMEM F12 medium with Fetal bovine Serum (FBS) overnight.

After pre-incubation, EAT and SAT tissues were washed and centrifuge d three times and cultured in medium without FBS for 24hours. Finally, we collected oozed medium (conditioned medium) and used for experiments.

Concentrations of Angptl2 in conditioned medium were measured by ELISA.

To study the effects of conditioned medium, we used “organo-culture” system. Isolated atrium from 8week old male Sprague-Dawley rats were placed on the porous membrane with the endothelial face toward the membrane. After that, loading medium (conditioned medium:culture medium = 1:4), culture medium (control), or recombinant Angptl2 were dropped onto the epicardial face of the atrium once a day and incubated for 7 days (37°C, 5% CO2).

Then, histological and immunohistochemical analysis were performed. We also performed quantitative reverse transcription–polymerase chain reaction (RT–PCR) analysis.

Next, we isolated and cultured neonatal rat fibroblast and loaded Angptl2 for 24 hours.After collected these cells, we performed western blotting analysis.

Results

Atria organo-culture incubated for 7 days with conditioned medium showed global fibrosis. At epicardial side, fibrotic area of EAT group was significantly greater compared to that of SAT and control group (P<0.05).

mRNA of Col1a1, col3a1 and TGFβ1 were significantly increased in EAT group compared with the SAT and control group.

And, the concentration of conditioned medium created from EAT was significant higher than that from SAT (P<0.05).

Then, we dropped 500 ng/ml of recombinant Angptl2 onto the rat atria. Fibrotic area of Angptl22 group significantly greater than that of control with increasing number of α-SMA positive cells, and mRNA of col3a1 and TGFβ1 were significantly increased in Angptl2 group compared with control group.

In cultured fibroblasts, α-SMA and p-ERK expression were increased in Angptl2 group measured by western blotting analysis.

Conclusions

Our results demonstrated that EAT rather than SAT induces atrial myocardial fibrosis. There is a possibility that Angptl2 effused from EAT plays a part in atrial fibrosis thought EAT paracrine effect.

Acknowledgement/Funding

ONO PHARMACEUTICAL CO

Hayabusa2 arrives at the carbonaceous asteroid 162173 Ryugu-A spinning top-shaped rubble pile

The Hayabusa2 spacecraft arrived at the near-Earth carbonaceous asteroid 162173 Ryugu in 2018. We present Hayabusa2 observations of Ryugu's shape, mass, and geomorphology. Ryugu has an oblate "spinning top" shape, with a prominent circular equatorial ridge. Its bulk density, 1.19 ± 0.02 grams per cubic centimeter, indicates a high-porosity (>50%) interior. Large surface boulders suggest a rubble-pile structure. Surface slope analysis shows Ryugu's shape may have been produced from having once spun at twice the current rate. Coupled with the observed global material homogeneity, this suggests that Ryugu was reshaped by centrifugally induced deformation during a period of rapid rotation. From these remote-sensing investigations, we identified a suitable sample collection site on the equatorial ridge.

The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes

The near-Earth carbonaceous asteroid 162173 Ryugu is thought to have been produced from a parent body that contained water ice and organic molecules. The Hayabusa2 spacecraft has obtained global multicolor images of Ryugu. Geomorphological features present include a circum-equatorial ridge, east-west dichotomy, high boulder abundances across the entire surface, and impact craters. Age estimates from the craters indicate a resurfacing age of [Formula: see text] years for the top 1-meter layer. Ryugu is among the darkest known bodies in the Solar System. The high abundance and spectral properties of boulders are consistent with moderately dehydrated materials, analogous to thermally metamorphosed meteorites found on Earth. The general uniformity in color across Ryugu's surface supports partial dehydration due to internal heating of the asteroid's parent body.

A Case of Feline T-cell Lymphoma with Tropism for Striated Muscle and Peripheral Nerve

An 11-year-old female American shorthair cat was presented with a 3-month history of hindlimb ataxia and knuckling of the left forelimb. Clinical abnormalities included weight loss, hyperaesthesia of the neck and back, cardiac murmur and systemic muscle atrophy. The cat died 10 days after the initial presentation and a necropsy examination was performed. Grossly, extensive pale lesions were seen in the wall of the left ventricle and the septum of the heart. There were no detectable masses in the heart, skeletal muscles or peripheral nerves. Histopathological examination revealed diffuse, extensive infiltration of atypical lymphoid cells in the heart; the cardiac muscles were markedly degenerate and atrophic and were replaced by the neoplastic cells. Neoplastic cells with similar morphology were seen in all specimens of the skeletal muscles and peripheral nerves. Clonality analysis of the paraffin wax-embedded heart tissue revealed a monoclonal rearrangement of the gene encoding the T-cell receptor γ chain. Based on these findings, the case was diagnosed as T-cell lymphoma with tropism for striated muscle and peripheral nerve.

Engineering Nanowire-Mediated Cell Lysis for Microbial Cell Identification

Researchers have demonstrated great promise for inorganic nanowire use in analyzing cells or intracellular components. Although a stealth effect of nanowires toward cell surfaces allows preservation of the living intact cells when analyzing cells, as a completely opposite approach, the applicability to analyze intracellular components through disrupting cells is also central to understanding cellular information. However, the reported lysis strategy is insufficient for microbial cell lysis due to the cell robustness and wrong approach taken so far ( i. e., nanowire penetration into a cell membrane). Here we propose a nanowire-mediated lysis method for microbial cells by introducing the rupture approach initiated by cell membrane stretching; in other words, the nanowires do not penetrate the membrane, but rather they break the membrane between the nanowires. Entangling cells with the bacteria-compatible and flexible nanowires and membrane stretching of the entangled cells, induced by the shear force, play important roles for the nanowire-mediated lysis to Gram-positive and Gram-negative bacteria and yeast cells. Additionally, the nanowire-mediated lysis is readily compatible with the loop-mediated isothermal amplification (LAMP) method because the lysis is triggered by simply introducing the microbial cells. We show that an integration of the nanowire-mediated lysis with LAMP provides a means for a simple, rapid, one-step identification assay (just introducing a premixed solution into a device), resulting in visual chromatic identification of microbial cells. This approach allows researchers to develop a microfluidic analytical platform not only for microbial cell identification including drug- and heat-resistance cells but also for on-site detection without any contamination.

PM2.5 Particle Detection in a Microfluidic Device by Using Ionic Current Sensing

We have demonstrated a PM_2.5 analysis method that adds information on the number concentration and size by using microfluidic-based ionic current sensing with a bridge circuit. The bridge circuit allows for suppression of the background current and the detection of small PM_2.5 particles, even if a relatively large micropore is used. This is the first demonstration of the detection of PM_2.5 particles via ionic current sensing; our method enables analyses of both the number concentration and size.

Biomolecular recognition on nanowire surfaces modified by the self-assembled monolayer

Molecular recognition is one of the key factors in designing biosensors due to which nanowires functionalized with molecular recognition have attracted a lot of attention as promising candidates for nanostructures embedded in biosensors. However, the difficulty in real-world applications with analytical specificity is that molecular recognition on nanowires mainly depends on antibody modification with multistep modification procedures. Furthermore, the antibody modification suffers from nonspecific adsorption of undesired proteins in body fluid on the nanowires, which causes false responses and lowers sensitivity. Herein, we propose biomolecular recognition using surface-modified nanowires via thiolated 2-methacryloxyethyl phosphorylcholine (MPC-SH). MPC-SH enables self-assembled monolayer (SAM) modification, which contributes to the reduction of nonspecific adsorption of biomolecules onto the nanowires, and the specific capture of a target protein is attained in the presence of calcium ions. Our concept demonstrates the recognition of the biomarker protein on nanowire surfaces modified by MPC-SH SAM with a single step modification procedure.

Robust Ionic Current Sensor for Bacterial Cell Size Detection

Ionic current sensing methods are useful tools for detecting sub- to several-micron scale particles such as bacteria. However, conventional commercially available ionic current sensing devices are not suitable for on-site measurement use because of inherent limitations on their robustness. Here, we proposed a portable robust ionic current sensor (Robust-ICS) using a bridge circuit that offers a high signal-to-noise (S/N) ratio by suppressing background current. Because the Robust-ICS can tolerate increased noise in current sensing, a simple, lightweight electromagnetic shield can be used and measurements under large electromagnetic noise conditions can be made. The weight of the device was lowered below 4 kg and outdoor particle detection measurements were completed successfully. Accuracy of size detection of Staphylococcus aureus ( S. aureus) was equivalent to that obtained by SEM imaging.

Unveiling massive numbers of cancer-related urinary-microRNA candidates via nanowires

Analyzing microRNAs (miRNAs) within urine extracellular vesicles (EVs) is important for realizing miRNA-based, simple, and noninvasive early disease diagnoses and timely medical checkups. However, the inherent difficulty in collecting dilute concentrations of EVs (<0.01 volume %) from urine has hindered the development of these diagnoses and medical checkups. We propose a device composed of nanowires anchored into a microfluidic substrate. This device enables EV collections at high efficiency and in situ extractions of various miRNAs of different sequences (around 1000 types) that significantly exceed the number of species being extracted by the conventional ultracentrifugation method. The mechanical stability of nanowires anchored into substrates during buffer flow and the electrostatic collection of EVs onto the nanowires are the two key mechanisms that ensure the success of the proposed device. In addition, we use our methodology to identify urinary miRNAs that could potentially serve as biomarkers for cancer not only for urologic malignancies (bladder and prostate) but also for nonurologic ones (lung, pancreas, and liver). The present device concept will provide a foundation for work toward the long-term goal of urine-based early diagnoses and medical checkups for cancer.