We demonstrate that symmetric or asymmetric gold nanoparticle dimers with substantial scattering cross sections and plasmon coupling can be produced with a perfectly controlled chemical environment ...and a high purity using a single DNA linker as short as 7 nm. A statistical analysis of the optical properties and morphology of single dimers is performed using darkfield and cryo-electron microscopies. These results, correlated to Mie theory calculations, indicate that the particle dimers are stretched in water by electrostatic interactions.
A photon interacts efficiently with an atom when its frequency corresponds exactly to the energy between two eigenstates. But at the nanoscale, homogeneous and inhomogeneous broadenings strongly ...hinder the ability of solid-state systems to absorb, scatter or emit light. By compensating the impedance mismatch between visible wavelengths and nanometre-sized objects, optical antennas can enhance light-matter interactions over a broad frequency range. Here we use a DNA template to introduce a single dye molecule in gold particle dimers that act as antennas for light with spontaneous emission rates enhanced by up to two orders of magnitude and single photon emission statistics. Quantitative agreement between measured rate enhancements and theoretical calculations indicate a nanometre control over the emitter-particle position while 10 billion copies of the target geometry are synthesized in parallel. Optical antennas can thus tune efficiently the photo-physical properties of nano-objects by precisely engineering their electromagnetic environment.
Plasmonic nanohole arrays have received significant attention, as they have highly advantageous optical properties for ultrasensitive and label-free biosensing applications. Currently, most of these ...subwavelength periodic apertures are mainly implemented on transparent materials, which results in multiple spectrally close transmission resonances. However, this spectral characteristic is not ideal for biosensing applications, as it complicates monitoring spectral variations. In this article, utilizing a hybrid substrate composed of a high refractive index dielectric interlayer over a transparent material, we show that gold nanohole arrays support spectrally isolated and well-defined plasmonic resonances that are easy to track. Compared to conventional configurations on transparent material, nanoholes on a hybrid substrate also exhibit plasmonic modes with well-preserved amplitudes, which is useful for reliable spectral monitoring. We show that nanohole arrays on a hybrid substrate are more sensitive to changes in surface conditions. Using a spectral integration method, which evaluates wavelength shifts in a large spectral window instead of monitoring only the plasmonic resonance wavelength, we obtain a detection limit as low as 2 × 10–5 RIU. Furthermore, we successfully demonstrate real-time monitoring of biomolecular binding interactions even at sub-1 ng/mL levels.
Plasmon-based optical antennas featuring a nanometer-sized gap can enhance the photophysical properties of solid-state quantum emitters by several orders of magnitude at room temperature. However, ...controlling the position and orientation of an isolated emitter in a metallic resonator, at the nanometer scale, has only been achieved in scanning probe geometries. Using radially polarized cylindrical vector beams and DNA-assembled gold nanoparticle dimers, we demonstrate the reproducible interaction of single dye molecules with the bright longitudinal mode of a plasmonic cavity, achieving decay rate enhancements of 2 orders of magnitude. These results demonstrate that interfacing efficiently isolated quantum emitters and optical nanoantennas is possible on a large scale.
Combination of age at diagnosis, stage and MYCN amplification stratifies neuroblastoma into low-risk and high-risk. We aimed to establish whether a microRNA (miRNA) signature could be associated with ...prognosis in both groups.
Microarray expression profiling of human miRNAs and quantitative reverse-transcriptase PCR of selected miRNAs were performed on a preliminary cohort of 13 patients. Results were validated on an independent cohort of 214 patients. The relationship between miRNA expression and the overall or disease-free survival was analysed on the total cohort of 227 patients using the log-rank test and the multivariable Cox proportional hazard model.
A total of 15 of 17 miRNAs that discriminated high-risk from low-risk neuroblastoma belonged to the imprinted human 14q32.31 miRNA cluster and two, miR-487b and miR-410, were significantly downregulated in the high-risk group. Multivariable analyses showed miR-487b expression as associated with overall survival and disease-free survival in the whole cohort, independently of clinical covariates. Moreover, miR-487b and miR-410 expression was significantly associated with disease-free survival of the non-MYCN-amplified favourable neuroblastoma: localised (stage 1, 2 and 3) and stage 4 of infant <18 months.
Expression of miR-487b and miR-410 shows predictive value beyond the classical high-/low-risk stratification and is a biomarker of relapse in favourable neuroblastoma.
An aureate dye: Confined electromagnetic fields in DNA‐templated gold nanoparticle dimers were tuned to engineer the fluorescence properties of organic dyes in water (see picture). Purified ...suspensions of hybrid metal–organic chromophores featured unprecedented photophysical properties, such as a short lifetime and low quantum yield but high brightness.
Background and Purpose
Azithromycin is a macrolide antibiotic with anti‐inflammatory and immunomodulating effects. Long‐term azithromycin therapy in patients with chronic lung diseases such as cystic ...fibrosis has been associated with increased antimicrobial resistance, emergence of hypermutable strains, ototoxicity and cardiac toxicity. The aim of this study was to assess the anti‐inflammatory effects of the non‐antibiotic azithromycin derivative CSY0073.
Experimental Approach
We compared the effects of CSY0073 with those of azithromycin in experiments on bacterial cultures, Pseudomonas aeruginosa biofilm, lung cells and mice challenged intranasally with P. aeruginosa LPS.
Key Results
In contrast to azithromycin, CSY0073 did not inhibit the growth of P. aeruginosa, Staphylococcus aureus or Haemophilus influenzae and had no effect on an established P. aeruginosa biofilm. Bronchoalveolar lavage (BAL) fluids and lung homogenates collected after the LPS challenge in mice showed that CSY0073 and azithromycin (200 mg·kg−1, i.p.) decreased neutrophil counts at 24 h and TNF‐α, CXCL1 and CXCL2 levels in the BAL fluid after 3 h and IL‐6, CXCL2 and IL‐1β levels in the lung after 3 h compared with the vehicle. However, only azithromycin reduced IL‐1β levels in the lung 24 h post LPS challenge. CSY0073 and azithromycin similarly diminished the production of pro‐inflammatory cytokines by macrophages, but not lung epithelial cells, exposed to P. aeruginosa LPS.
Conclusions and Implications
Unlike azithromycin, CSY0073 had no antibacterial effects but it did have a similar anti‐inflammatory profile to that of azithromycin. Hence, CSY0073 may have potential as a long‐term treatment for patients with chronic lung diseases.
Nasopharyngeal carcinomas: an update Spano, J.-P.; Busson, P.; Atlan, D. ...
European Journal of Cancer,
10/2003, Letnik:
39, Številka:
15
Book Review, Journal Article
Recenzirano
Among the group of head and neck cancers, nasopharyngeal carcinomas (NPC) represent a distinct entity in terms of their epidemiology, clinical presentation, biological markers, carcinogenic risk ...factors, prognostic factors, treatment and outcome. Undifferentiated NPC (UCNT), the most frequent histological type, is endemic in certain regions, especially in South East Asia. The disease has also been associated with the presence of the Epstein–Barr Virus (EBV). Although NPC is a radiosensitive and chemosensitive tumour, a substantial number of patients develop local recurrence or distant metastases. For patients with locoregional advanced disease, it is well known that conventional radiotherapy is insufficient in terms of both the local control rates and distant metastases. New techniques of radiation and new combined radiotherapy and chemotherapy modalities have been evaluated in numerous clinical trials in recent years. The purpose of this article is to review the current knowledge in terms of the epidemiology, biology, prognosis, management and outcome of patients with NPC.
Introduction Exosomes are nanovesicles found in large quantities in biological fluids and tumors of patients with nasopharyngeal carcinoma (NPC). These tumor exosomes play an important role in tumor ...progression due to their immunosuppressive properties. In addition, it has been reported that the frequency and suppressor functions of CD4 + CD25highFOXP3 + CD127low regulatory T cells (Treg) are also higher in NPC patients than healthy donors. Interactions between NPC-derived exosomes and Treg remain unknown. Here we investigated their ability to induce, expand, activate and recruit human Treg. Material and methods Treg recruitment by exosomes derived from NPC cell lines (C15/C17-Exo), exosomes isolated from NPC patients’ plasma (Patient-Exo), and CCL20 was tested in vitro using Boyden chamber assays and in vivo using a xenograft SCID mouse model ( N = 5), both in the presence and absence of anti-CCL20 monoclonal antibodies (mAb). Impact of these NPC exosomes (NPC-Exo) on Treg phenotype and function was determined using adapted assays (FACS, Q-PCR, ELISA and MLR). Experiments were performed in comparison with exosomes derived from plasma of healthy donors (HD-Exo). Results CCL20 allowed the intra-tumoral recruitment of human Treg. NPC-Exo also facilitated Treg recruitment (3.30 ± 0.34-fold increase, P < .001), which was statistically significantly inhibited ( P < .001) by an anti-CCL20 blocking mAb. NPC-Exo also recruited conventional CD4 + CD25- T cells and mediated their conversion into inhibitory CD4 + CD25high cells. Moreover, NPC-Exo statistically significantly enhanced ( P = 0.0048) the expansion of human Treg, inducing the generation of Tim3Low Treg with increased expression of CD25 and FOXP3. Finally, NPC-Exo induced an overexpression of cell markers associated with Treg phenotype, properties and recruitment capacity. For example, GZMB mean fold change was 21.45 ± 1.75. These results were consistent with a stronger suppression of responder cells’ proliferation ( P < .001), and the secretion of immunosuppressive cytokines (IL10, TGFB1). Conclusion Interactions between NPC-Exo and Treg represent a newly defined mechanism that may be involved in regulating peripheral tolerance by tumors and in supporting immune evasion in human NPC.
PDF
