Selective high-order resonance in asymmetric plasmonic nanostructures stimulated by vortex beams.

Orbital angular momentum (OAM) of light has the potential to induce high-order transitions of electrons in atoms by compensating for the OAM required. However, due to the dark spot situating at the focal center of the OAM beam, high-order transitions are typically weak. In this study, we demonstrate efficient and selective high-order resonances in symmetric and asymmetric plasmonic nanoparticles that are comparable in size to the waist radius of the OAM beam. In a symmetric nanoparticle configured with a complete nanoring lying on the focal center, there is a pure high-order resonance obeying the law of conservation of angular momentum during the interaction between OAM light and the nanosystem. In an asymmetric nanoparticle configured with an complete ring off the beam center or a splitting nanoring, there are multiple resonances whose resonance orders are influenced by the ring's geometry, position, orientation, and photon OAM. Thus, high-order resonances in the symmetric and asymmetric plasmonic nanostructures are selectively stimulated using vortex beams. Our results may help to understand and control OAM-involved light-material interactions of asymmetric nanosystems.

KIAA1199 promotes oxaliplatin resistance and epithelial mesenchymal transition of colorectal cancer via protein O-GlcNAcylation.

Oxaliplatin is a commonly used platinum drug for colorectal cancer (CRC). However, the treatment of CRC by oxaliplatin usually fails because of drug resistance, which results in a huge challenge in the therapy of CRC. Elucidation of molecular mechanisms may help to overcome oxaliplatin resistance of CRC. In our study, we revealed that KIAA1199 can promote oxaliplatin resistance of CRC. Mechanistically, KIAA1199 prevents oxaliplatin mediated apoptosis via up-regulated PARP1 derived from reduced endoplasmic reticulum stress induced by protein O-GlcNAcylation. In the meantime, KIAA1199 can also trigger epithelial mesenchymal transition by stabilizing SNAI1 protein via O-GlcNAcylation. Therefore, KIAA1199 has great potential to be a novel biomarker, therapeutic target for oxaliplatin resistance and metastasis of CRC.

SPP standing waves within plasmonic nanocavities.

Surface plasmons usually take two forms: surface plasmon polaritons (SPP) and localized surface plasmons (LSP). Recent experiments demonstrate an interesting plasmon mode within plasmonic gaps, showing distinct characters from the two usual forms. In this investigation, by introducing a fundamental concept of SPP standing wave and an analytical model, we reveal the nature of the recently reported plasmon modes. The analytical model includes SPP propagating and SPP reflection within a metal-insulator-metal (MIM) cavity, which is rechecked and supplemented by numerical simulations. We systematically analyze SPP standing waves within various nanocavities. During the discussion, some unusual phenomena have been explained. For example, the hot spot of a nanodimer could be off-tip, depending on the order of standing wave mode; and that a nanocube on metal film can be viewed as a nanocube dimer with the same separation. And many other interesting phenomena have been discussed, such as dark mode of SPP standing wave and extraordinary optical transmission. The study gives a comprehensive understanding of SPP standing waves, and may promote the applications of cavity plasmons in ultrasensitive bio-sensings.

Prognostic value of circulating microRNA-21-5p and microRNA-126 in patients with acute myocardial infarction and infarct-related artery total occlusion.

Background: Cardiovascular disease, including acute myocardial infarction (AMI), is a major global cause of mortality and morbidity. Specificity and sensitivity limit the utility of classic diagnostic biomarkers for AMI. Therefore, it is critical to identify novel biomarkers for its accurate diagnosis. Cumulative studies have demonstrated that circulating microRNAs (miRs) participate in the pathophysiological processes of AMI and are promising diagnostic biomarkers for the condition. This study aimed to ascertain the diagnostic accuracy of circulating miR-21-5p and miR-126 used as biomarkers in patients with AMI and infarct-related artery total occlusion (IR-ATO) or infarct-related blood-vessel recanalization (IR-BVR). Methods: The expression of miR-21-5p and miR-126 was examined separately in 50 healthy subjects, 51 patients with IR-ATO AMI, and 49 patients with IR-BVR AMI using quantitative real-time polymerase chain reaction. Results: When compared with the control group, the IR-ATO AMI group exhibited increased miR-21-5p (p < 0.0001) and miR-126 (p < 0.0001), and the IR-BVR AMI group exhibited increased miR-21-5p (p < 0.0001). However, there was no significant difference in miR-126 between the IR-BVR AMI and the control groups. A Spearman's correlation coefficient showed a strong correlation was found between miR-21-5p, miR-126, cardiac troponin-I, and creatine kinase isoenzyme in all three groups, while a receiver operating characteristic analysis revealed that miR-21-5p and miR-126 exhibited considerable diagnostic accuracy for IR-ATO AMI. Conclusion: Circulating miR-21-5p and miR-126 may be promising prognostic biomarkers for patients with AMI and IR-ATO.

20 watt-level single transverse mode narrow linewidth and tunable random fiber laser at 1.5 µm band.

High power 1.5 µm band fiber lasers are of great importance for many practical applications. Generally, the technical targets including high average output power, narrow linewidth, temporally suppressed intensity dynamics, high spectral purity, single transverse mode lasing, and excellent robustness are the major concerns when constructing a high-performance laser source. Here, we demonstrate the highest output power of a wavelength tunable 1.5 µm band random fiber laser based on the active fiber gain mechanism to the best of our knowledge. A master oscillator power-amplifier (MOPA) configuration is employed to greatly boost the output power to 20 watt-level with a single transverse mode lasing and the same linewidth as the seed, benefiting from the spectral broadening free feature when employing the random fiber laser as the seed. This work not only enriches the progress of random fiber laser, but also provides an attractive alternative in realizing high performance lasing light source at 1.5 µm band.

Analysis of the potential role of fission yeast PP2A in spindle assembly checkpoint inactivation.

As a surveillance mechanism, the activated spindle assembly checkpoint (SAC) potently inhibits the E3 ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) to ensure accurate chromosome segregation. Although the protein phosphatase 2A (PP2A) has been proposed to be both, directly and indirectly, involved in spindle assembly checkpoint inactivation in mammalian cells, whether it is similarly operating in the fission yeast Schizosaccharomycer pombe has never been demonstrated. Here, we investigated whether fission yeast PP2A is involved in SAC silencing by following the rate of cyclin B (Cdc13) destruction at SPBs during the recovery phase in nda3-KM311 cells released from the inhibition of APC/C by the activated spindle checkpoint. The timing of the SAC inactivation is only slightly delayed when two B56 regulatory subunits (Par1 and Par2) of fission yeast PP2A are absent. Overproduction of individual PP2A subunits either globally in the nda3-KM311 arrest-and-release system or locally in the synthetic spindle checkpoint activation system only slightly suppresses the SAC silencing defects in PP1 deletion (dis2Δ) cells. Our study thus demonstrates that the fission yeast PP2A is not a key regulator actively involved in SAC inactivation.

Toroidal dipole-modulated dipole-dipole double-resonance in colloidal gold rod-cup nanocrystals for improved SERS and second-harmonic generation.

Colloidal metal nanocrystals (NCs) show great potential in plasmon-enhanced spectroscopy owing to their attractive and structure-depended plasmonic properties. Herein, unique Au rod-cup NCs, where Au nanocups are embedded on the one or two ends of Au nanorods (NRs), are successfully prepared for the first time via a controllable wet-chemistry strategy. The Au rod-cup NCs possess multiple plasmon modes including transverse and longitudinal electric dipole (TED and LED), magnetic dipole (MD), and toroidal dipole (TD) modulated LED resonances, producing large extinction cross-section and huge near-field enhancements for plasmon-enhanced spectroscopy. Particularly, Au rod-cup NCs with two embedded cups show excellent surface-enhanced Raman spectroscopy (SERS) performance than Au NRs (75.6-fold enhancement excited at 633 nm) on detecting crystal violet owing to the strong electromagnetic hotspots synergistically induced by MD, LED, and TED-based plasmon coupling between Au cup and rod. Moreover, the strong TD-modulated dipole-dipole double-resonance and MD modes in Au rod-cup NCs bring a 37.3-fold enhancement of second-harmonic generation intensity compared with bare Au NRs, because they can efficiently harvest photoenergy at fundamental frequency and generate large near-field enhancements at second-harmonic wavelength. These findings provide a strategy for designing optical nanoantennas for plasmon-enhanced applications based on multiple plasmon modes. Electronic Supplementary Material: Supplementary material (SEM image of Au rod-one-cup NCs; TEM image of Au/PbS hybrids; SEM image of Au rod-two-cup NCs; low-amplification SEM image of Au rod-two-cup NCs; experimental extinction and calculated electric field distributions of Au NR excited at different wavelengths; calculated absorption and scattering spectra of Au rod-one-cup NCs; schematic illustration of the cut plane and the corresponding magnetic field distribution under L3 excitation; Raman spectra of CV (10-6 M) adsorbed on Au rod-cup NCs with different cup sizes; calculated magnetic field distribution of Au rodcup NCs excited at 532 and 633 nm; calculated electric field distributions of Au rod-one-cup NC excited at 600 nm along TE and LE; the models of Au rod-cup NCs used in the simulations) is available in the online version of this article at 10.1007/s12274-022-4562-5.

Pretreatment BAN Score Based on Body-mass-index, Albumin and Neutrophil-lymphocyte Ratio Could Predict Long-term Survival for Patients with Operable Esophageal Squamous Cell Carcinoma.

Background: The present study was designed to examine the prognostic value of a systemic inflammation marker-BAN score, which was established based on body-mass-index (BMI), albumin (ALB) and neutrophil-lymphocyte ratio (NLR) in resectable esophageal squamous cell carcinoma (ESCC) patients. Methods: A total of 420 newly diagnosed ESCC patients in our hospital between January 2008 and December 2013 were included. Their baseline characteristics were retrospectively reviewed and collected. BAN score was calculated as (BMI × ALB/ NLR). The optimal cutoff value for BAN score was defined as 28.0 in terms of survival. Patients were then allocated to high BAN (≥ 28.0) and low BAN (< 28.0) score groups. Results: Pretreatment BAN score was significantly associated with tumor length, white blood cell count, BMI, ALB and NLR levels. However, no significant difference was observed in patients' age, gender, tumor location, degree of differentiation, depth of invasion, lymph node involvement, tumor-node-metastasis (TNM) stage or other variables between groups. Moreover, those with high pretreatment BAN scores (≥ 28.0) tended to have favorable disease free survival (DFS) [hazard ratio (HR), 0.650; 95% confidence interval (CI), 0.481-0.877; P = 0.005] and overall survival (OS) (HR, 0.608; 95% CI, 0.445-0.829; P = 0.002) by univariate analysis. Furthermore, multivariate Cox regression analysis suggested that high BAN score (≥ 28.0) could serve as an independent predictor for both DFS (HR, 0.726; 95% CI, 0.532-0.993; P = 0.045) and OS (HR, 0.670; 95% CI, 0.485-0.927; P = 0.016). Conclusions: Pretreatment BAN score could independently predict long-term survival for resectable ESCC patients.

Effects of heavy ions (12C6+) on malignant melanoma B16F10 cells.

Background: This study aimed to investigate the effects of heavy ion (12C6+) irradiation on the proliferation, apoptosis, cell cycle, migration, and epithelial-mesenchymal transition (EMT) of B16F10 cells. Methods: The B16F10 cells, which is a malignant melanoma cell line widely used in research, irradiated by 12C6+ and X-ray were detected by Hoechst 33342/propidium iodide double staining, Western blot, flow cytometry, and cell scratch tests to evaluate cell proliferation, expression of apoptosis-related proteins, G2/M phase arrest, cell migration, cell invasion and EMT. Results: Compared with the same physical X-ray dose, 12C6+ could effectively inhibit the proliferation of B16F10 cells, inhibit the expression of B-cell lymphoma-2 (Bcl-2) and cellular-myelocytomatosis viral oncogene (c-Myc), and induce the expression of Bax to promote the apoptosis of B16F10 cells. After 12C6+ irradiation, the B16F10 cells exhibited G2/M phase arrest. B16F10 cells were highly sensitive to 12C6+ irradiation. Moreover, compared with X-ray, the 12C6+ irradiation significantly inhibited the migration of B16F10 cells and inhibited extracellular matrix cleavage, induced E-cadherin expression, enhanced cell adhesion, and further inhibited cell invasion, migration, and EMT. Conclusions: The B16F10 cells were highly radiosensitive to 12C6+. Compared with X-ray, B16F10 cells irradiated by 12C6+ significantly reduced the expressions of matrix metalloproteinases to inhibit extracellular matrix cleavage and, thus, effectively inhibit cell invasion and metastasis. However, although the issue of the different therapeutic effects of heavy ion and X-ray radiotherapy on malignant melanoma was investigated and preliminary research results were obtained, several problems must be further studied.

Interactions between Plasmonic Nanoantennas and Vortex Beams.

The orbital angular momentum (OAM) of light offers a new degree of freedom for light-matter interactions, yet how to control such interactions with this physical dimension remains open. Here, by developing a numerical method enabling optical OAM simulations, we provide insights into complex plasmon behaviors with the physical dimension of OAM, and we prove in theory that plasmonic nanostructures can function as efficient antennas to intercept and directionally reradiate the power of OAM beams. The interplay between optical OAM and spin angular momentum (SAM) generates novel particle polarizations and radiations, which were inaccessible before. For arrayed nanoparticles, coherent surface plasmons with specific phase retardations determined by OAM of the beams enable directional power radiations, making a phased array antenna. These findings expand our knowledge of nanoplasmonics in the OAM area and are promising for quantum information processing and dynamic sensing of ultraweak biosignals.

Perturbation of kinetochore function using GFP-binding protein in fission yeast.

Using genetic mutations to study protein functions in vivo is a central paradigm of modern biology. Single-domain camelid antibodies generated against GFP have been engineered as nanobodies or GFP-binding proteins (GBPs) that can bind GFP as well as some GFP variants with high affinity and selectivity. In this study, we have used GBP-mCherry fusion protein as a tool to perturb the natural functions of a few kinetochore proteins in the fission yeast Schizosaccharomyces pombe. We found that cells simultaneously expressing GBP-mCherry and the GFP-tagged inner kinetochore protein Cnp1 are sensitive to high temperature and microtubule drug thiabendazole (TBZ). In addition, kinetochore-targeted GBP-mCherry by a few major kinetochore proteins with GFP tags causes defects in faithful chromosome segregation. Thus, this setting compromises the functions of kinetochores and renders cells to behave like conditional mutants. Our study highlights the potential of using GBP as a general tool to perturb the function of some GFP-tagged proteins in vivo with the objective of understanding their functional relevance to certain physiological processes, not only in yeasts, but also potentially in other model systems.

Synthesis of AuAg/Ag/Au open nanoshells with optimized magnetic plasmon resonance and broken symmetry for enhancing second-harmonic generation.

The cooperation of magnetic and electric plasmon resonances in cup-shaped metallic nanostructures exhibits significant capability for second-harmonic generation (SHG) enhancement. Herein, we report an approach for synthesizing Au open nanoshells with tunable numbers and sizes of openings on a template of six-pointed PbS nanostars. The morphology of Au nanoshells is controlled by adjusting the amount of HAuCl4, and the characteristic shapes of pointed nanocaps, open nanoshells, and hollow nanostars are obtained. Owing to the collaboration of electric and magnetic plasmon resonance modes, the Au nanoshells exhibit significantly broadened and highly tunable optical responses. Furthermore, the morphology-dependent SHG of the Au nanoshells shows two maximal SHG intensities, corresponding to four-opening and one-opening Au nanoshells with appropriate opening sizes. Ag/Au and AuAg/Ag/Au open nanoshells were further investigated to achieve enhanced SHG. By adjusting the thickness of the Ag shell, the SHG intensity of Ag/Au open nanoshells reaches a maximum due to the gradient field at the AuAg bimetallic interface. After replacing the Ag shells with Au shells, the SHG intensity of AuAg/Ag/Au open nanoshells reaches a maximum due to further symmetry breaking. These findings provide a strategy to prepare colloidal metal nanocrystals with prospective applications ranging from nonlinear photonic nanodevices to biospectroscopy and photocatalysis.

3D chaos lidar system with a pulsed master oscillator power amplifier scheme.

We investigated the characteristics of chaos-modulated pulses amplified by a pulsed master oscillator power amplifier (MOPA) for application in a new chaos lidar system in this study. Compared with the loss modulation applied in a continuous-wave (CW) time-gating scheme, the pulsed MOPA scheme could generate chaos-modulated pulses with much higher peak power, resulting in an improved peak-to-standard deviation of sidelobe level (PSLstd) in correlation-based lidar detection. When the pulsed MOPA scheme was applied at a duty cycle of 0.1% and pulse repetition frequency of 20 kHz, which correspond to specifications compliant with eye safety regulations, it outperformed the CW time-gating scheme with respect to PSLstd by 15 dB. For the first time, we applied the chaos lidar system with the pulsed MOPA scheme to execute high-resolution, high-precision three-dimensional (3D) face profiling from a distance of 5 m. We also added the corresponding PSLstd value to each pixel in the point clouds to generate false-color images; thus, we obtained 3D images of a scene with multiple objects at a range of up to 20 m.

Efficacy and Safety of Anti-Programmed Cell Death Protein-1 Immunotherapy for Advanced Hepatocellular Carcinoma With Pulmonary Metastases: A Single-Center, Retrospective Study.

BACKGROUND: Anti-programmed cell death protein-1 immunotherapy has been approved as a new treatment option for advanced hepatocellular carcinoma (HCC) based on the promising results of several studies. METHODS: This retrospective study included 71 patients with advanced HCC treated with anti-programmed cell death protein-1 immunotherapy between June 1, 2017 and September 30, 2020 at the First Affiliated Hospital of Anhui Medical University. Responses to pulmonary metastases were evaluated. RESULTS: The median follow-up duration was 7.73 months (95% confidence interval (CI), 4.48-10.98). Of 71 patients, the overall response rate (ORR) and disease control rate (DCR) were 32% (23/71) and 73% (52/71), respectively. The median progression-free survival (PFS) and overall survival (OS) were 4.90 (95% CI, 2.71-7.09) and 20.23 (95% CI, 6.87-33.59) months, respectively. Forty-two patients had HCC pulmonary metastases, whereas 29 did not have pulmonary metastasis. No significant differences were observed in the ORR (38% [16/42] vs. 24% [7/29], P = 0.22) and DCR (74% [31/42] vs. 72% [21/29], P = 0.90) between groups. In patients with pulmonary metastases, the median disease control duration of pulmonary lesions was significantly longer than extrapulmonary lesions (Not Reached vs. 12.37 months, P = 0.048). Pulmonary metastases were not associated with an increased incidence of adverse events (67% vs. 62%, P = 0.69). CONCLUSIONS: Anti-programmed cell death protein-1 immunotherapy showed promising efficacy and safety in patients with advanced HCC, with good responses observed in pulmonary metastases. The mechanism underlying the differences in responses between pulmonary and extrapulmonary metastases requires further investigation.

Effects of enhanced external counterpulsation on exercise capacity and quality of life in patients with chronic heart failure: A meta-analysis.

BACKGROUND: This meta-analysis aimed to synthesize randomized controlled trials to evaluate the effects of enhanced external counterpulsation (EECP) on exercise capacity and quality of life in patients with chronic heart failure (CHF). METHODS: Both English and Chinese databases were searched from their inception to June 30, 2020 (PubMed, EMBASE, Cochrane Library, CINAHL (EBSCO), Web of Science for English publications and Chinese Biomedical Database, China National Knowledge Infrastructure, Wanfang Data for Chinese publication). Titles, abstracts, and full-text articles were screened against study inclusion criteria: randomized controlled trials studying EECP intervention for patients with CHF. The meta-analysis was conducted with Revman 5.3 or STATA 16.0. RESULTS: Eight randomized controlled trials were included. EECP induced significant improvement in 6-min walking distance (WMD=84.79 m; 95% CI, 47.64 to 121.95; P < .00001). Moreover, EECP was beneficial for left ventricular ejection fraction (SMD = 0.64; 95% CI,0.29 to 1.00; P = .0004), and N-terminal pro brain natriuretic peptide (SMD = -0.61; 95%CI, -1.20 to -0.01; P = 0.04).However, compared with the control groups, EECP did not significantly reduce the Minnesota Living with Heart Failure Questionnaire scores(WMD, -9.28; 95% CI, -19.30 to 0.75; P = 0.07). CONCLUSIONS: Despite heterogeneity and risk of bias, this meta-analysis confirms that EECP can improve exercise capacity in CHF patients, especially the elderly. However, the evidence that EECP improves the quality of life in patients with CHF is still insufficient. More and larger well-designed randomized controlled trials are still warranted. REGISTRATION INFORMATION: PROSPERO registration no. CRD 42020188848.

Tunable Size Dependence of Quantum Plasmon of Charged Gold Nanoparticles.

The quantum behavior of surface plasmons has received extensive attention, benefiting from the development of exquisite nanotechnology and the diverse applications. Blueshift, redshift, and nonshift of localized surface plasmon resonances (LSPRs) have all been reported as the particle size decreases and enters the quantum size regime, but the underlying physical mechanism to induce these controversial size dependences is not clear. Herein, we propose an improved semiclassical model for modifying the dielectric function of metal nanospheres by combining the intrinsic quantized electron transitions and surface electron injection or extraction to investigate the plasmon shift and LSPR size dependence of the charged Au nanoparticles. We experimentally observe that the nonmonotonic blueshift of LSPRs with size for Au nanoparticles is turned into an approximately monotonic blueshift by increasing the electron donor concentration in the reduction solution, and it can also be transformed to an approximately monotonic redshift after surface passivation by ligand molecules. Moreover, we demonstrate controlled blueshift and redshift for the electron and hole plasmons in Cu_{2-x}S@Au core-shell nanoparticles by injecting electrons. The experimental observations and the theoretical calculations clarify the controversial size dependences of LSPR reported in the literature, reveal the critical role of surface electron injection or extraction in the transformation between the different size dependences of LSPRs, and are helpful for understanding the nature of surface plasmons in the quantum size regime.

Nanostructured Black Aluminum Prepared by Laser Direct Writing as a High-Performance Plasmonic Absorber for Photothermal/Electric Conversion.

Utilizing the abundant and renewable solar energy to address the global energy shortage and water scarcity is promising. Great effort has been devoted to photothermal conversion for its typically full-spectrum utilization and high efficiency. Here, the coral-like micro/nanostructure was fabricated on an aluminum sheet by a facile laser direct writing technology. The nanocluster and microscale branches of corals endowed this black aluminum with broad-band plasmonic absorption and rapid heat transfer from the light absorption region to substrate. The black aluminum achieved ultrahigh solar absorbance of over 92.6% (>95.1% in the visible range) and excellent light heating ability (>90.6 °C under 1.0 sun). With good photothermal properties, this plasmonic absorber was used in a state-of-the-art eight-layer membrane distillation system, producing a water yield of up to 2.40 kg m-2 h-1 and a high solar conversion efficiency of 166.5% under 1-sun irradiation. Photothermal electricity was also achieved based on this system with a thermoelectric generator, with a water yield of 0.89 kg m-2 h-1 and a maximum electrical power output of 7.21 µW cm-2 under 1.0 sun. Considering the excellent performance of the plasmon-enhanced black aluminum, this work provides an alternative and feasible route toward high-efficient utilization of the solar energy.

Aberrantly upregulated FAM83H-AS1 facilitates malignant progression of esophageal squamous cell carcinoma.

The biological roles of the newly identified long non-coding RNA family with sequence similarity 83 member H antisense 1 (FAM83H-AS1) in esophageal squamous cell carcinoma (ESCC) have remained largely elusive. In the present study, it was determined that, in comparison with paired para-tumorous tissues or normal esophageal epithelial cells, FAM83H-AS1 expression in cancer tissues and cell lines was markedly upregulated. Furthermore, FAM83H-AS1 expression was significantly elevated in patients with ESCC and lymph node metastasis or a late TNM stage, while no association with any other clinicopathological characteristics was detected. Furthermore, the overall and disease-free survival, as assessed by the Kaplan-Meier method, were significantly shortened in patients with high FAM83H-AS1 expression. A functional study then uncovered that knockdown of FAM83H-AS1 significantly suppressed the proliferation and migration of ESCC cells. The present results suggested that FAM83H-AS1 may facilitate the malignant progression of ESCC and may be utilized as a prognostic predictor and possibly a novel therapeutic target in ESCC that warrants further exploration.

Structure-Adjustable Gold Nanoingots with Strong Plasmon Coupling and Magnetic Resonance for Improved Photocatalytic Activity and SERS.

Au nanoingots, on which an Au nanosphere is accurately placed in an open Au shell, are synthesized through a controllable hydrothermal method. The prepared Au nanoingots exhibit an adjustable cavity structure, strong plasmon coupling, tunable magnetic plasmon resonance, and prominent photocatalytic and SERS performances. Au nanoingots exhibit two resonance peaks in the extinction spectrum, one (around 550 nm) is ascribed to electric dipole resonance coming from the central Au, and the other one (650-800 nm) is ascribed to the magnetic dipole resonance originating from the open Au shell. Numerical simulations verify that the intense electric and magnetic fields locate in the bowl-shaped nanogap between the Au nanosphere and shell, and they can be further optimized by changing the size of the outer Au shell. Au nanoingots with the largest shell have the strongest electric field because of large-area plasmon coupling, while Au nanoingots with the largest shell opening size have the strongest magnetic field. As a result, the structure-adjustable Au nanoingots show a high tunability and enhancement of catalytic reduction of p-nitrophenol and SERS detection of Rhodamine B. Specially, Au nanoingots with the largest shell size exhibit the highest catalytic activity and Raman signals at 532 nm excitation. However, Au nanoingots with the largest shell opening size have the highest photocatalytic activity with light irradiation (λ > 420 nm) and exhibit the best SERS performance at 785 nm excitation.

Multi-interfacial plasmon coupling in multigap (Au/AgAu)@CdS core-shell hybrids for efficient photocatalytic hydrogen generation.

Plasmon coupling induced intense light absorption and near-field enhancement have vast potential for high-efficiency photocatalytic applications. Herein, (Au/AgAu)@CdS core-shell hybrids with strong multi-interfacial plasmon coupling were prepared through a convenient strategy for efficient photocatalytic hydrogen generation. Bimetallic Au/AgAu cores with an adjustable number of nanogaps (from one to four) were primarily synthesized by well-controlled multi-cycle galvanic replacement and overgrowth processes. Extinction tests and numerical simulations synergistically revealed that the multigap Au/AgAu hybrids possess a gap-dependent light absorption region and a local electric field owing to the multigap-induced multi-interfacial plasmon coupling. With these characteristics, hetero-photocatalysts prepared by further coating of CdS shells on multigap Au/AgAu cores exhibited a prominent gap-dependent photocatalytic hydrogen production activity from water splitting under light irradiation (λ > 420 nm). It is found that the hydrogen generation rates of multigap (Au/AgAu)@CdS have an exponential improvement compared with that of pure CdS as the number of nanogaps increases. In particular, four-gap (Au/AgAu)@CdS core-shell catalysts displayed the highest hydrogen generation rate, that is 96.1 and 47.2 times those of pure CdS and gapless Au@CdS core-shell hybrids. These improvements can be ascribed to the strong plasmon absorption and near-field enhancement induced by the multi-interfacial plasmon coupling, which can greatly improve the light-harvesting efficiency, offer more plasmonic energy, and boost the generation and separation of electron-hole pairs in the multigap catalysts.