A carregar...
Projeto de investigação
Associated Laboratory for Green Chemistry - Clean Technologies and Processes
Financiador
Autores
Publicações
Advances in Supported Nanoparticle Catalysts
Publication . Carabineiro, Sónia Alexandra Correia; LAQV@REQUIMTE; DQ - Departamento de Química; MDPI - Multidisciplinary Digital Publishing Institute
Tetra dansylamides substituted cyclen and cyclam macrocycles as fluorescent sensing probes for metal ions and temperature-responsive materials in dopped polymers
Publication . Pereira-Gomes, Inês; Duarte, Frederico Gonçalo do Vale; Dobrikov, Georgi M.; Slavchev, Ivaylo; Kurutos, Atanas; Capelo-Martínez, José Luis; Santos, H. M.; Lodeiro, Carlos; DQ - Departamento de Química; LAQV@REQUIMTE; Elsevier
Two novel tetra-dansyl derivatives incorporating cyclen (1,4,7,10-tetraazacyclododecane) and cyclam (1,4,8,11-tetraazacyclotetradecane) macrocycles have been synthesized, thoroughly characterized, and their photophysical properties examined, both in solution and in the solid state. These compounds exhibit fluorescence emission with quantum yields up to 40 %, varying significantly with different solvents. They also display positive solvatofluorochromic behavior, with emissions ranging from green to yellow colours. Kamlet-Taft studies were conducted to better understand solute-solvent interactions. Furthermore, aggregation-induced emission was observed in solutions with high water content, confirmed via dynamic light scattering. Given the intrinsic properties of these compounds, their potential for environmental remediation was explored through metal ion sensing studies. Compounds L1 and L2 demonstrated high sensitivity to Cu2+ and Hg2+ ions, significantly modulating their emission, with L2 capable of detecting and quantifying Hg2+ concentrations as low as 2–3 μM. Additionally, the solid-state emission of these compounds encouraged an investigation into their potential as temperature sensors. Several doped polymer thin films were fabricated, establishing a linear relationship with temperature beyond their melting point. These findings suggest that these tetra-chromophoric compounds hold promise as molecular thermometers.
Comparative Chemical Profiling and Antimicrobial/Anticancer Evaluation of Extracts from Farmed versus Wild Agelas oroides and Sarcotragus foetidus Sponges
Publication . Varamogianni-Mamatsi, Despoina; Nunes, Maria João; Marques, Vanda; Anastasiou, Thekla I.; Kagiampaki, Eirini; Vernadou, Emmanouela; Dailianis, Thanos; Kalogerakis, Nicolas; Branco, Luís C.; Rodrigues, Cecília M. P.; Sobral, Rita G.; Gaudêncio, Susana P.; Mandalakis, Manolis; LAQV@REQUIMTE; DQ - Departamento de Química; DCV - Departamento de Ciências da Vida; UCIBIO - Applied Molecular Biosciences Unit; MDPI - Multidisciplinary Digital Publishing Institute
Marine sponges are highly efficient in removing organic pollutants and their cultivation, adjacent to fish farms, is increasingly considered as a strategy for improving seawater quality. Moreover, these invertebrates produce a plethora of bioactive metabolites, which could translate into an extra profit for the aquaculture sector. Here, we investigated the chemical profile and bioactivity of two Mediterranean species (i.e., Agelas oroides and Sarcotragus foetidus) and we assessed whether cultivated sponges differed substantially from their wild counterparts. Metabolomic analysis of crude sponge extracts revealed species-specific chemical patterns, with A. oroides and S. foetidus dominated by alkaloids and lipids, respectively. More importantly, farmed and wild explants of each species demonstrated similar chemical fingerprints, with the majority of the metabolites showing modest differences on a sponge mass-normalized basis. Furthermore, farmed sponge extracts presented similar or slightly lower antibacterial activity against methicillin-resistant Staphylococcus aureus, compared to the extracts resulting from wild sponges. Anticancer assays against human colorectal carcinoma cells (HCT-116) revealed marginally active extracts from both wild and farmed S. foetidus populations. Our study highlights that, besides mitigating organic pollution in fish aquaculture, sponge farming can serve as a valuable resource of biomolecules, with promising potential in pharmaceutical and biomedical applications.
Precise control of silver nanoplate dimensions and optical properties via pH, EDTA and AMP mediated synthesis
Publication . Lodeiro, Carlos; Capelo-Martínez, José Luis; Fernández-Lodeiro, Javier; Nuti, Silvia; Fernández-Lodeiro, Adrián; DQ - Departamento de Química; LAQV@REQUIMTE; Elsevier
We present a seed-mediated synthesis method for producing silver nanoplates (AgNPTs) with customizable size and thickness, ensuring high yield and precise optical properties. This approach leverages ethylenediaminetetraacetic acid (EDTA) as a key component in the synthesis process, utilizing small single-crystal silver seeds. The interaction between Ag+ ions and EDTA at varying pH levels dynamically regulates silver complexation and reduction kinetics during seed overgrowth, leading to the formation of truncated nanoplates with superior optical responses. By adjusting the pH within the range of 8–10.5, we can manipulate the growth of the nanoplates, enabling a flexible optical response ranging from 519 to 1006 nm due to changes in their size and thickness. Additionally, nanoplate overgrowth extends plasmon resonance up to approximately 2000 nm. The incorporation of Adenosine 5′ monophosphate (AMP) not only enhances nanoplate stability but also allows for precise thickness adjustment independent of growth kinetics. This method provides a systematic approach to tailor nanoplate morphology and optical properties with unprecedented precision. The role of EDTA is attributed to its complexation ability with Ag+ and its assistance in facet evolution, supported by density functional theory (DFT) simulations of surface energies modified by EDTA adsorption. Furthermore, DFT calculations confirm that AMP can further modify the surface energies of different facets, enabling precise thickness control
Reusable and highly sensitive SERS immunoassay utilizing gold nanostars and a cellulose hydrogel-based platform
Publication . Oliveira, Maria João; Cunha, Inês; de Almeida, Miguel P.; Calmeiro, Tomás; Fortunato, Elvira; Martins, Rodrigo; Pereira, Luís; Byrne, Hugh J.; Pereira, Eulália; Águas, Hugo; Franco, Ricardo; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; UCIBIO - Applied Molecular Biosciences Unit; DQ - Departamento de Química; RSC - Royal Society of Chemistry
The development of robust and sensitive point-of-care testing platforms is necessary to improve patient care and outcomes. Surface-enhanced Raman scattering (SERS)-based immunosensors are especially suited for this purpose. Here, we present a highly sensitive and selective SERS immunoassay, demonstrating for example the detection of horseradish peroxidase (HRP), in a sandwich format. The strength of our biosensor lies in merging: (i) SERS-immunotags based on gold nanostars, allowing exceptional intense SERS from attached Raman probes, covalent attachment of anti-HRP antibodies by a simple chemical method providing exceptional antigen binding activity; (ii) the ease of preparation of the capture platform from a regenerated cellulose-based hydrogel, a transparent material, ideal for microfluidics applications, with low background fluorescence and Raman signal, particularly suited for preserving high activity of the covalently bound anti-HRP antibodies. The sandwich complexes formed were characterised by atomic force microscopy, and by scanning electron microscopy coupled with electron diffraction spectroscopy; and (iii) the robustness of the simple Classical Least Squares method for SERS data analysis, resulting in superior discrimination of SERS signals from the background and much better data fitting, compared to the commonly used peak integral method. Our SERS immunoassay greatly improves the detection limits of traditional enzyme-linked immunosorbent assay approaches, and its performance is better or comparable to those of existing SERS-based immunosensors. Our approach successfully overcomes the main challenges of application at point-of-care, including increasing reproducibility, sensitivity, and specificity, associated with an environmentally friendly and robust design. Also, the proposed design withstands several cycles of regeneration, a feature absent in paper-SERS immunoassays and this opens the way for sensitive multiplexing applications on a microfluidic platform.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDB/50006/2020