Plexcitonic nanorattles as highly efficient SERS‐encoded tags

Plexcitonic nanoparticles exhibit strong light‐matter interactions, mediated by localized surface plasmon resonances, and thereby promise potential applications in fields such as photonics, solar cells, and sensing, among others. Herein, these light‐matter interactions are investigated by UV‐visible and surface‐enhanced Raman scattering (SERS) spectroscopies, supported by finite‐difference time‐domain (FDTD) calculations. Our results reveal the importance of combining plasmonic nanomaterials and J‐aggregates with near‐zero‐refractive index. As plexcitonic nanostructures nanorattles are employed, based on J‐aggregates of the cyanine dye 5,5,6,6‐tetrachloro‐1,1‐diethyl‐3,3‐bis(4‐sulfobutyl)benzimidazolocarbocyanine (TDBC) and plasmonic silver‐coated gold nanorods, confined within mesoporous silica shells, which facilitate the adsorption of the J‐aggregates onto the metallic nanorod surface, while providing high colloidal stability. Electromagnetic simulations show that the electromagnetic field is strongly confined inside the J‐aggregate layer, at wavelengths near the upper plexcitonic mode, but it is damped toward the J‐aggregate/water interface at the lower plexcitonic mode. This behavior is ascribed to the sharp variation of dielectric properties of the J‐aggregate shell close to the plasmon resonance, which leads to a high opposite refractive index contrast between water and the TDBC shell, at the upper and the lower plexcitonic modes. This behavior is responsible for the high SERS efficiency of the plexcitonic nanorattles under both 633 nm and 532 nm laser illumination. SERS analysis showed a detection sensitivity down to the single‐nanoparticle level and, therefore, an exceptionally high average SERS intensity per particle. These findings may open new opportunities for ultrasensitive biosensing and bioimaging, as superbright and highly stable optical labels based on the strong coupling effect.Agencia Estatal de Investigación | Ref. PID2019-108854RA-I00Agencia Estatal de Investigación | Ref. PID2019-108954RB-I00Agencia Estatal de Investigación | Ref. PRE2020-096163Agencia Estatal de Investigación | Ref. PRE2020- 094237Fundação para a Ciência e a Tecnologia | Ref. 2022.03164Universidade de Vigo/CISU

Tunable narrowband Excitonic Optical Tamm States enabled by a metal-free all-organic structure

Optical Tamm States (OTS) are confined optical modes that can occur at the interface between two highly reflective structures. However, due to the strong reflectance required, their implemen-tation with highly processable and metal-free flexible materials has proven challenging. Herein, we develop the first structure supporting OTS based only on organic polymeric materials, demon-strating a photonic platform based on non-critical, widely available, and easily processable mate-rials. The structures fabricated present large areas and consist of a narrowband multi-layered polymeric Distributed Bragg Reflector (DBR) followed by a thin film of J-aggregate molecular exci-tonic material that can act as a highly reflective surface within a narrowband range. We take ad-vantage of the narrowband spectral response of the DBR and of the reflective molecular layer to tune the OTS band by varying the periodicity of the multilayer, opening the door for the fabrica-tion of OTS structures based on lightweight integrable excitonic devices with cost-effective proce-dures.Comment: 15 pages, 8 (3+5) figures, supplementary information include

Práticas artísticas no ensino básico e secundário

A educação pela arte faz-se através dos seus materiais, da sua operação, da transformação das matérias em ideias novas, em novas coisas. No seu sucesso está implicada uma literacia, uma capacidade interpretativa, ou crítica, sobre a semiosfera cada vez mais povoada, saturada de mensagens parasitárias. A educação implica uma leitura do mundo (Paulo Freire), que se projeta na interpretação de todas as camadas de expressão contemporânea, muitas vezes massificada, por vezes ainda identitária e significativa. Fala-se aqui de valorizar a identidade, exercer a pedagogia da diferença através de uma capacidade problematizadora. No seu contexto, podem exercer-se pedagogias que exploram a visão crítica do artista em interação com a escola, o artista em residência, no movimento A/ R/ Tography. Ou também exercer-se uma pedagogia triangular, centrando a arte, o contexto, a produção e a sua leitura como uma metodologia (Ana Mae Barbosa). O contexto contemporâneo é pós digital, os conteúdos não pesam nos suportes, e transmitem-se por “dentes azuis” ou redes com muitos Gs (G de Geração sem peso que sucede ao peso da aceleração gravítica). Neste campo pode delinear-se uma metodologia que alicerça o projeto ancorado nos estudos críticos sobre Cultura Visual (Fernando Hernández). Digamos que as práticas pedagógicas se cruzam em diversas direções, tacteando eficácias, expressões, capacidades, inovação. O contexto é cada vez mais voraz: a pele da cultura gosta de massagens (Kerkhove; McLuhan). A Matéria-Prima de que se fala nesta revista é aquela que devolve ao seu lugar um ponto crítico da pós modernidade: o do significante. Os sintagmas são sempre processos, e neles se formam as subjectividades, ou seja, as identidades: no desenrolar do ser, onde se produz verdadeiramente o sentido, bem junto do aqui-e-agora onde está a Matéria-Prima (Foucault).info:eu-repo/semantics/publishedVersio

OmniSARS2: a highly sensitive and specific RT-qPCR-based COVID-19 diagnostic method designed to withstand SARS-CoV-2 lineage evolution

Extensive transmission of SARS-CoV-2 during the COVID-19 pandemic allowed the generation of thousands of mutations within its genome. While several of these become rare, others largely increase in prevalence, potentially jeopardizing the sensitivity of PCR-based diagnostics. Taking advantage of SARS-CoV-2 genomic knowledge, we designed a one-step probe-based multiplex RT-qPCR (OmniSARS2) to simultaneously detect short fragments of the SARS-CoV-2 genome in ORF1ab, E gene and S gene. Comparative genomics of the most common SARS-CoV-2 lineages, other human betacoronavirus and alphacoronavirus, was the basis for this design, targeting both highly conserved regions across SARS-CoV-2 lineages and variable or absent in other Coronaviridae viruses. The highest analytical sensitivity of this method for SARS-CoV-2 detection was 94.2 copies/mL at 95% detection probability (~1 copy per total reaction volume) for the S gene assay, matching the most sensitive available methods. In vitro specificity tests, performed using reference strains, showed no cross-reactivity with other human coronavirus or common pathogens. The method was compared with commercially available methods and detected the virus in clinical samples encompassing different SARS-CoV-2 lineages, including B.1, B.1.1, B.1.177 or B.1.1.7 and rarer lineages. OmniSARS2 revealed a sensitive and specific viral detection method that is less likely to be affected by lineage evolution oligonucleotide–sample mismatch, of relevance to ensure the accuracy of COVID-19 molecular diagnostic methods.Fundação para a Ciência e a Tecnologia | Ref. UIDB / 50026/2020Fundação para a Ciência e a Tecnologia | Ref. UIDP / 50026/2020Fundação para a Ciência e a Tecnologia | Ref. 2020.03113.CEECINDXunta de Galicia | Ref. CT850A-2European Commission | Ref. NORTE-01-0145-FEDER-072555European Commission | Ref. NORTE-01-0145- FEDER-00003