Plasmonic Annular Nanotrenches with 1 nm Nanogaps for Detection of SARS-CoV-2 Using SERS-Based Immunoassay

This study represents the synthesis of a novel class of nanoparticles denoted as annular Au nanotrenches (AANTs). AANTs are engineered to possess embedded, narrow circular nanogaps with dimensions of approximately 1 nm, facilitating near-field focusing for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via a surface-enhanced Raman scattering (SERS)-based immunoassay. Notably, AANTs exhibited an exceedingly low limit of detection (LOD) of 1 fg/mL for SARS-CoV-2 spike glycoproteins, surpassing the commercially available enzyme-linked immunosorbent assay (ELISA) by 6 orders of magnitude (1 ng/mL from ELISA). To assess the real-world applicability, a study was conducted on 50 clinical samples using an SERS-based immunoassay with AANTs. The results revealed a sensitivity of 96% and a selectivity of 100%, demonstrating the significantly enhanced sensing capabilities of the proposed approach in comparison to ELISA and commercial lateral flow assay kits.

Combinatorial Effect of Tricomponent Dual-Rim Nanoring Building Blocks: Label-Free SERS Detection of Biomolecules

Detecting weakly adsorbing molecules via label-free surface-enhanced Raman scattering (SERS) has presented a significant challenge. To address this issue, we propose a novel approach for creating tricomponent SERS substrates using dual-rim nanorings (DRNs) made of Au, Ag, and CuO, each possessing distinct functionalities. Our method involves depositing different metals on Pt nanoring skeletons to obtain each nanoring with varying surface compositions while maintaining a similar size and shape. Next, the mixture of these nanorings is transferred into a monolayer assembly with homogeneous intermixing on a solid substrate. The surface of the CuO DRNs has dangling bonds (Cu2+) that facilitate the strong adsorption of carboxylates through the formation of chelating bonds, while the combination of Au and Ag DRNs significantly enhances the SERS signal intensity through a strong coupling effect. Notably, the tricomponent assemblies enable the successful SERS-based analysis of biomolecules such as amino acids, proteins, nucleobases, and nucleotides.

Ready-to-Use Free-Standing Super-Powder Made with Complex Nanoparticles for SERS

This study presents a straightforward and efficient synthetic approach for producing high-yield, ready-to-use, free-standing super-powder. The synthesis protocol demonstrates versatility, enabling the creation of assemblies from various nanoparticle morphologies and compositions without the need for specific substrates. Au nanorings are employed as building blocks for fabricating the super-powder, which can be used in surface-enhanced Raman spectroscopy (SERS). The distinctive aspect ratio of the ring nanoframes allows the formation of densely packed columnar assemblies on the substrate, aligning the exposed gaps perpendicular to the laser beam. This arrangement significantly enhances the charge separation among nanorings, leading to a highly focused near-field that is applicable to SERS analysis. The SERS detection feasibility of this powder in both pre- and post-contamination conditions is demonstrated. Using a wide range of building blocks, encompassing various shapes (for instance, rods, hexagons, cubes, cuboctahedrons, elongated dodecahedrons, triangular rings, double-rings, elongated dodecahedra frames, cuboctahedra frames, and double-walled frames), the generalizability of the process for synthesizing super-powders with diverse morphologies is substantiated.

Step-by-Step Nanoscale Top-Down Blocking and Etching Lead to Nanohexapods with Cartesian Geometry

In this research, we designed a stepwise synthetic method for Au@Pt hexapods where six elongated Au pods are arranged in a pairwise perpendicular fashion, sharing a common point (the central origin in a Cartesian-coordinate-like hexapod shape), featured with tip-selectively decorated Pt square nanoplates. Au@Pt hexapods were successfully synthesized by applying three distinctive chemical reactions in a stepwise manner. The Pt adatoms formed discontinuous thin nanoplates that selectively covered six concave facets of a Au truncated octahedron and served as etching masks in the succeeding etching process, which prevented underlying Au atoms from being oxidized. The subsequent isotropic etching proceeded radially, starting from the bare Au surface, carving the central nanocrystal in a concave manner. By controlling the etching conditions, Au@Pt hexapods were successfully fabricated, wherein the core Au domain is connected to six protruding arms, which hold Pt nanoplates at the ends. Due to their morphology, Au@Pt hexapods feature distinctive optical properties in the near-infrared region, as a proof of concept, allowing for surface-enhanced Raman spectroscopy (SERS)-based monitoring of in situ CO electrooxidation. We further extended our synthetic library by tailoring the size of the Pt nanoplates and neck widths of Au branches, demonstrating the validity of selective blocking and etching-based colloidal synthesis.

Octahedron in a Cubic Nanoframe: Strong Near-Field Focusing and Surface-Enhanced Raman Scattering

Here, we describe the synthesis of a plasmonic particle-in-a-frame architecture in which a solid Au octahedron is enclosed by a Au cubic nanoframe. The octahedra are positioned inside and surrounded by outer Au cubic nanoframes, creating intra-nanogaps within a single entity. Six sharp vertexes in the Au octahedra point toward the open (100) facets of the cubic nanoframes. This allows not only efficient interactions with the surroundings but also tip-enhanced electromagnetic near-field focusing at the sharp tips of the octahedra, combined with intraparticle coupling. The solid core-frame shell structure enhances near-field focusing, giving rise to a heightened concentration of "hot spots". This effect enables highly sensitive detection of 2-naphthalenethiol and thiram, indicating these substrates for use in surface-enhanced Raman spectroscopy-related applications.

Three-Dimensional Au Octahedral Nanoheptamers: Single-Particle and Bulk Near-Field Focusing for Surface-Enhanced Raman Scattering

Herein, we present a synthetic approach to fabricate Au nanoheptamers composed of six individual Au nanospheres interconnected through thin metal bridges arranged in an octahedral configuration. The resulting structures envelop central Au nanospheres, producing Au nanosphere heptamers with an open architectural arrangement. Importantly, the initial Pt coating of the Au nanospheres is a crucial step for protecting the inner Au nanospheres during multiple reactions. As-synthesized Au nanoheptamers exhibit multiple hot spots formed by nanogaps between nanospheres, resulting in strong electromagnetic near-fields. Additionally, we conducted surface-enhanced Raman-scattering-based detection of a chemical warfare agent simulant in the gas phase and achieved a limit of detection of 100 ppb, which is 3 orders lower than that achieved using Au nanospheres and Au nanohexamers. This pseudocore-shell nanostructure represents a significant advancement in the realm of complex nanoparticle synthesis, moving the field one step closer to sophisticated nanoparticle engineering.

Plasmonic Dodecahedral-Walled Elongated Nanoframes for Surface-Enhanced Raman Spectroscopy

Here, elongated pseudohollow nanoframes composed of four rectangular plates enclosing the sides and two open-frame ends with four ridges pointing at the tips for near-field focusing are reported. The side facets act as light-collecting domains and transfer the collected light to the sharp tips for near-field focusing. The nanoframes are hollow inside, allowing the gaseous analyte to penetrate through the entire architecture and enabling efficient detection of gaseous analytes when combined with Raman spectroscopy. The resulting nanostructures are named Au dodecahedral-walled nanoframes. Synthesis of the nanoframes involves shape transformation of Au nanorods with round tips to produce Au-elongated dodecahedra, followed by facet-selective Pt growth, etching of the inner Au, and regrowth steps. The close-packed assembly of Au dodecahedral-walled nanoframes exhibits an attomolar limit of detection toward benzenethiol. This significant enhancement in SERS is attributed to the presence of a flat solid terrace for a large surface area, sharp edges and vertices for strong electromagnetic near-field collection, and open frames for effective analyte transport and capture. Moreover, nanoframes are applied to detect chemical warfare agents, specifically mustard gas simulants, and 20 times higher sensitivity is achieved compared to their solid counterparts.

Au Octahedral Nanosponges: 3D Plasmonic Nanolenses for Near-Field Focusing

Here, we report the synthesis of three-dimensional plasmonic nanolenses for strong near-field focusing. The nanolens exhibits a distinctive structural arrangement composed of nanoporous sponge-like networks within their interior. We denote these novel nanoparticles as "Au octahedral nanosponges" (Au Oh NSs). Employing a carefully planned multistep synthetic approach with Au octahedra serving as sacrificial templates, we successfully synthesized Au Oh NSs in solution. The porous domains resembling sponges contributed to enhanced scattering and absorption of incident light within metal ligaments. This optical energy was subsequently transferred to the nanospheres at the vertex, where near-field focusing was maximized. We named this observed enhancement a "lightning-sphere effect". Using single particle-by-particle surface-enhanced Raman scattering (SERS), we optimized the morphological dimensions of the spheres and porous domains to achieve the most effective near-field focusing. In the context of bulk SERS measurements targeting weakly adsorbing analytes (2-chloroethyl phenyl sulfide) in the gas phase, we achieved a low detection limit of 10 ppb. For nonadsorbing species (dimethyl methyl phosphonate), utilization of hybrid SERS substrates consisting of Au Oh NSs and metal-organic frameworks as gas-adsorbing intermediate layers was highly effective for successful SERS detection.

Multi-Layered PtAu Nanoframes and Their Light-Enhanced Electrocatalytic Activity via Plasmonic Hot Spots

Here, the rational design of complex PtAu double nanoframes (DNFs) for plasmon-enhanced electrocatalytic activity toward the methanol oxidation reaction (MOR) is reported. The synthetic strategy for the DNFs consists of on-demand multiple synthetic chemical toolkits, including well-faceted Au growth, rim-on selective Pt deposition, and selective Au etching steps. DNFs are synthesized by utilizing Au truncated octahedrons (TOh) as a starting template. The outer octahedral (Oh) nanoframes (NFs) nest the inner TOh NFs, eventually forming DNFs with a tunable intra-nanogap distance. Residual Au adatoms on Pt skeletons act as light entrappers and produce plasmonic hot spots between inner and outer frames through localized surface plasmon resonance (LSPR) coupling, which promotes enhanced electrocatalytic activity for the MOR. Importantly, the correlation between the gap-induced hot carriers and electrocatalytic activity is evaluated. The highest catalytic activity is achieved when the gap is the narrowest. To further harness their light-trapping capability, hierarchically structured triple NFs (TNFs) are synthesized, wherein three NFs are entangled in a single entity with a high density of hot regions, exhibiting superior electrocatalytic activity toward the MOR with a sixfold larger current density under light irradiation compared to the dark conditions.

Bimetallic alloy Ag@Au nanorings with hollow dual-rims focus near-field on circular intra-nanogaps

Here, we report a highly sensitive and reliable surface enhanced Raman scattering (SERS)-based immunoassay using bimetallic alloy Ag@Au hollow dual-rim nanorings (DRNs) where two hollow nanorings with different diameters are concentrically overlapped and connected by thin metal ligaments, forming circular hot-zones in the intra-nanogaps between the inner and outer rims. Pt DRNs were first prepared, and then Ag was deposited on the surface of the Pt skeleton, followed by Au coating, resulting in alloy Ag@Au hollow DRNs. The chemical stability of Au and the high optical properties of Ag are incorporated into a single entity, Ag@Au hollow DRNs, enabling strong single-particle SERS activity and biocompatibility through surface modification with thiol-containing functionalities. When Ag@Au hollow DRNs were utilized as nanoprobes for detecting human chorionic gonadotropin (HCG) hormone through a SERS-based immunoassay, a very low limit of detection of 10 pM with high reliability was achieved, strongly indicating their advantage as ultrasensitive SERS nanoprobes.

Microrobotics for Precision Biofilm Diagnostics and Treatment

Advances in small-scale robotics and nanotechnology are providing previously unimagined opportunities for new diagnostic and therapeutic approaches with high precision, control, and efficiency. We designed microrobots for tetherless biofilm treatment and retrieval using iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality as building blocks. We show 2 distinct microrobotic platforms. The first system is formed from NPs that assemble into aggregated microswarms under magnetic fields that can be controlled to disrupt and retrieve biofilm samples for microbial analysis. The second platform is composed of 3-dimensional (3D) micromolded opacifier-infused soft helicoids with embedded catalytic-magnetic NPs that can be visualized via existing radiographic imaging techniques and controlled magnetically inside the root canal, uninterrupted by the soft and hard tissues surrounding the teeth in an ex vivo model. These microrobots placed inside the root canal can remove biofilms and be efficiently guided with microscale precision. The proof-of-concept paradigm described here can be adapted to target difficult-to-reach anatomical spaces in other natural and implanted surfaces in an automated and tether-free manner.

Effect of relative humidity on preeclampsia

PURPOSE OF INVESTIGATION

The authors aimed to determine the relationship between meteorological variables and hypertension in pregnancy by using data from a national weather database.

MATERIALS AND METHODS

For this population-based observational study, the database of the Korea National Health Insurance (KNHI) Claims of the Health Insurance Review and Assessment Service (HIRA) and Korea Meteorological Administration was used. The 48,275 women with preeclampsia among 2,495,383 women who gave birth were included. Monthly meteorological factors and preeclampsia prevalence for five years were statistically analyzed.

RESULTS

Among temperature, relative humidity, sunlight duration, and rainfall, only relative humidity had a significant inverse correlation with the preeclampsia prevalence (p < 0.001). The other meteorological factors were not associated with preeclampsia.

CONCLUSION

Relative humidity may be a significant factor for of the development of preeclampsia. Further monitoring of weather parameters during the entire pregnancy period may be the best method for verifying the present results in the development of preeclampsia.

Neural Axis Metastasis from Metachronous Pulmonary Basaloid Carcinoma Developed after Chemotherapy & Radiation Therapy of Uterine Cervical Carcinoma

Multiple primary or secondary malignancies after anticancer therapy were recently reported to be increasing in frequency. The authors describe a case of metachronous metastatic pulmonary basaloid carcinoma to the central nervous system that was discovered after chemotherapy and radiation therapy for cervical uterine carcinoma. Two different types of cancer developed within some interval. There's the possibility that a secondary pulmonary neoplasm developed after the chemotherapy and radiotherapy conducted as cervical cancer treatment.

CD14 Receptor Gene Promoter Polymorphism: Awakening Maternal Immunity during Pregnancy

We investigated whether monocyte CD14 receptor gene promoter polymorphisms were associated with the development and severity of pre-eclampsia. We genotyped the CD14-260 C/T polymorphism in 36 preeclamptic patients and 52 healthy pregnant controls. A total of 30.6% and 69.4% of pre-eclamptic patients had the C and T alleles, respectively, and 48.0% and 52.0% of the controls, respectively. More pre-eclamptic patients were TT homozygotes compared with controls (50.0% versus 13.5%). In pre-eclamptic patients, the TT homozygotes exhibited a significantly higher mean systolic blood pressure compared with the non-TT homozygotes (173 ± 28 mmHg versus 153 ± 22 mmHg). We also noted a tendency towards increased proteinuria and placental abruption in the TT homozygotes compared with the non-TT homozygotes. We conclude that CD14 gene promoter polymorphisms appear to be a risk factor for pre-eclampsia. With further research, these findings might form the basis of a prognostic tool for pre-eclampsia.

Effects of water temperature on mortality in Megalocytivirus-infected rock bream Oplegnathus fasciatus (Temminck et Schlegel) and development of protective immunity

Rock bream iridovirus (RBIV) causes huge losses, especially in rock bream Oplegnathus fasciatus. Rock bream injected with RBIV and held at 29, 26, 23 or 20 °C had 100% mortality. Conversely, all infected fish held at 17 °C survived even after the temperature was progressively increased to 26 °C at 100 dpi. Rock bream exposed to virus and held for 2, 4 and 7 days at 23/26 °C before the temperature was reduced to 17 °C had mortality rates of 26.6/73.2%, 66.6/100% and 93.4/100%, respectively, through 100 dpi. When surviving fish had the water temperature increased from 17 to 26 °C at 100 dpi, they did not exhibit signs of disease and had low virus copy numbers (below 10(3)). To investigate the development of a protective immune, rock bream were infected with RBIV and held at 23 °C before shifting the water temperature to 17 °C at 4 dpi. All injected fish survived until 120 dpi. While 100% of the previously unexposed fish died, 80.2% of the previously infected fish survived. When the survivors were rechallenged again at 160 dpi, no further mortality occurred. The high survival rate of fish following rechallenge with RBIV indicates that protective immunity was established in the surviving rock bream.

Aroma-active components of Lycii fructus (kukija)

The fruit of Lycii fructus has been used as a tonic medicine and a long-term healthy food without side effect in Asia. An increase in the demand for natural healthy food, L. fructus has been thought as a source of healthy foods. For its value adding, its character impact aromas were isolated by using direct solvent extraction with vacuum transfer and identified by using gas chromatography olfactometry (GC-O) and GC-mass spectrometry (GC-MS). Thirty-three odor compounds were sniffed at GC-O, each trial equipped with DB-5MS and HP-WAX capillary column. The most contributing odor compounds in L. fructus were (E)-2-heptenal (green, mushroomy), 1-heptanol (planty, oily), hexanal (planty), 3-octanol (mushroomy, planty), 1-octen-3-ol (mushroomy), and 2-methyl-2-butenoic acid (pungent, planty), which might be produced by enzymatic oxidation and/or oxidation of lipids and carotenes, resulting in undesirable aromas.

Finger-assisted stretching technique for cesarean section

OBJECTIVE

To compare the perioperative outcomes of two cesarean section methods, the finger-assisted stretching technique (FAST), based on a modified Joel-Cohen method, with the traditional technique.

METHODS

A retrospective review of the records of 416 women who underwent cesarean sections at Guro Hospital, Seoul, Korea, between May 1993 and December 2001 was performed. Of the 416 women, 283 underwent cesarean sections with FAST and 133 with the traditional technique.

RESULTS

Operative time was significantly shorter with FAST (15.3 vs. 42.6 min, P<.05), and FAST was associated with lower blood loss (601 vs. 928 mL, P<.05) and shorter hospital stay (3.7 vs. 6.5 days, P<.05). There were no significant differences in wound infection, voiding difficulty, and postoperative adhesions between the two methods.

CONCLUSION

These results suggest that FAST may be the better technique.

Establishment and characterization of two new cell lines derived from flounder, Paralichthys olivaceus (Temminck & Schlegel)

Two new cell cultures from flounder, Paralichthys olivaceus (Temminck & Schlegel), flounder fin (FFN) cells from fin tissue and flounder spleen (FSP) cells from spleen tissue, were established and characterized. The cells multiplied well in Eagle's minimum essential medium, supplemented with 10% foetal bovine serum, and have been subcultured more than 100 times, becoming continuous cell lines. Modal diploid chromosome number of FFN and FSP cells was 64 and 62, respectively. Polymerase chain reaction products were obtained from FFN and FSP cells with primer sets ofmicrosatellite markers of flounder. Optimal growth temperature was 20 degrees C and consisted of epithelioid cells. FFN and FSP cells showed cytopathic effects after inoculation of infectious pancreatic necrosis virus, marine birnavirus, chum salmon virus, infectious haematopoietic necrosis virus, spring viraemia of carp virus and hirame rhabdovirus. Thus these new cell lines may be useful for studying a wide range of fish viruses.

Development of a virtual speaking simulator using Image Based Rendering

The fear of speaking is often cited as the world's most common social phobia. The rapid growth of computer technology has enabled the use of virtual reality (VR) for the treatment of the fear of public speaking. There are two techniques for building virtual environments for the treatment of this fear: a model-based and a movie-based method. Both methods have the weakness that they are unrealistic and not controllable individually. To understand these disadvantages, this paper presents a virtual environment produced with Image Based Rendering (IBR) and a chroma-key simultaneously. IBR enables the creation of realistic virtual environments where the images are stitched panoramically with the photos taken from a digital camera. And the use of chroma-keys puts virtual audience members under individual control in the environment. In addition, real time capture technique is used in constructing the virtual environments enabling spoken interaction between the subject and a therapist or another subject.

Detection of epidermal growth factor receptor in the serum of patients with cervical carcinoma

Epidermal growth factor receptor (EGFR) is overexpressed in a variety of malignancies, including breast, lung, gastric, and cervical carcinoma. Its overexpression has been associated with disease progression or poor prognosis in patients with cervical carcinoma. In the present study, the levels of EGFR were determined in serum from 38 patients with cervical carcinoma [invasive or recurrent carcinoma (n = 26) and carcinoma in situ (CIS; n = 12)] and 38 healthy female controls using ELISA. The mean serum level for EGFR in patients with invasive or recurrent carcinoma (165 +/- 60 fmol/ml) was significantly elevated (P < 0.0001) compared with that of healthy controls (66 +/- 17 fmol/ml) and also higher (P = 0.015) than that of patients with CIS (126 +/- 25 fmol/ml). In addition, there was a significant difference in the mean serum levels of EGFR between patients with CIS and healthy controls (P < 0.0001). Thirty-five patients (92%) with cervical carcinoma [invasive or recurrent (n = 24) and CIS (n = 11)] had elevated serum, EGFR levels above the cutoff value of 100 fmol/ml (defined as 2 SD above the mean of the controls). In conclusion, the serum EGFR level was elevated in a significant proportion of patients with cervical carcinoma, and it demonstrated an increasing tendency according to disease progression from normal tissue through CIS to invasive cervical carcinoma. Therefore, it may have a potential usefulness as a biological marker of cervical carcinoma.

Distribution of genotypes in the 5' untranslated region of hepatitis C virus in Korea

Hepatitis C virus (HCV) is an important human pathogen that can cause acute and chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. Recently, partial and entire sequence data from HCV isolates have been reported, suggesting various genotypes of HCV. The genotype may be correlated with the progression of hepatitis and maybe a prognostic marker of treatment. Thus, the availability of an assay for typing HCV RNA is important. This study developed a convenient method for genotyping HCV into six groups by PCR-RFLP with four restriction endonucleases (BstUI, HaeIII, NciI, RsaI) in the 5' untranslated region (UTR) of HCV. The HCV genotypes from 169 patients with HCV infections in Korea were analysed. Two genotypes, type 1b and type 2a, accounted for 47.3% and 42.6% of HCV infections, respectively.

Deletions of 9p21 and TP53 in bladder cancer

The objective of this study was to characterize the alterations of 9p21 and TP53 in Korean transitional bladder cancer and to assess the relationship between the histopathologic parameter and the alteration of these genes. Allele loss in 29 surgically resected transitional cell carcinoma was examined by using the multiplex PCR with 7 and 1 microsatellite markers for 9p21 and TP53, respectively. Twenty-one (72%) demonstrated allele loss at 9p21 and/or TP53. Deletion at the 9p21 region was detected in 17(61%) of 28 informative cases at one or more loci, and LOH at TP53 was found in 12(55%) of 22 informative cases. Of 7 microsatellite markers for 9p21, allele loss occurred the most frequently at locus D9S162(69%) and D9S104(69%). Additionally, hemizygous deletion was slightly more common than homozygous deletion. Deletion at 9p21 and TP53 was not related with increased grade. These results suggest that the alteration of 9p21 may be an early event in the development of Korean bladder cancer, while p53 gene may be involved in early event of some bladder cancers as well as in their late events.

Characterization of an essential histidine residue in thermophilic malate dehydrogenase

Heat-stable malate dehydrogenase isolated from Thermus flavus AT62 was completely inactivated by treatment with diethylpyrocarbonate. The inactivation was accompanied by the loss of 1.2 histidine residues per subunit of the enzyme. The enzyme was protected from inactivation by NADH. The enzyme was also inactivated by dye-sensitized photooxidation. Methionine residues, in addition to histidine residues, were destroyed in the inactivated enzyme. Kinetic analyses of the inactivation indicated that the pK value of the residue involved in the inactivation was 8.20 at 25.0 degrees C and 7.52 at 60.0 degrees C. From the pK values and the heat of ionization calculated from the van't Hoff plot of pKs, a histidine residue was identified to be primarily involved in the inactivation. The effect of temperature on the pK value of the essential group in this enzyme from a thermophilic organism is discussed.