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Antimicrobial profile and Turn-On sensing of cyanide and water traces using a dual chromophoric Dansyl-Acridine conjugate as multifunctional system
Publication . Duarte, Frederico; Pereira-Gomes, Inês; Dobrikov, Georgi M.; Galhano, Joana; Gomes, Clara S.B.; Kurutos, Atanas; Santos, Hugo M.; Oliveira, Elisabete; Paula Duarte, Maria; Luis Capelo-Martinez, José; Lodeiro, Carlos; Faculdade de Ciências e Tecnologia (FCT); LAQV@REQUIMTE; DQ - Departamento de Química; MEtRICS - Centro de Engenharia Mecânica e Sustentabilidade de Recursos; Elsevier
9-aminocridine derivatives bearing a dimethylmethanimidamide, L1, and the dyad conjugate dansyl-acridine, L2, were synthesized and their ability to be used as multifunctional materials using different polymer matrixes was investigated. L1 was found to modulate its emission in the presence of traces of water with a turn-on effect and to this end was used for the detection of water traces in organic solvents with a LOD and LOQ of 0.0028 and 0.0121 (V%) in acetonitrile, respectively. Due to the observed acidochromism for this compound and the different behaviour in acetonitrile and chloroform due to different stabilization of the excited state a turn-off and turn-on effect was observed for respective solvents. PMMA polymer doped films aided on the elucidation for this compound to be used as a sensor of strong acids. Furthermore, compound L2 was found fruitful for the detection of cyanide through an acid base anion sensing. Incorporation of these compounds in PVA:PVP polymer films and Irogran® microparticles were carried out to assess their antimicrobial profile.
Innovative colorimetric detection of clinical Gram-negative bacteria using low-cost bacteriostatic barbiturate polymers
Publication . Galhano, Joana; Kurutos, Atanas; Dobrikov, Georgi M.; Duarte, Maria Paula; Santos, Hugo M.; Capelo-Martínez, José Luis; Lodeiro, Carlos; Oliveira, Elisabete; DQ - Departamento de Química; LAQV@REQUIMTE; MEtRICS - Centro de Engenharia Mecânica e Sustentabilidade de Recursos; Elsevier
This study introduces the synergistic antibacterial activity derived from the combination of barbituric acid derivatives with PVC, PMMA and PMMMA polymers. The barbiturates - C1, C2, and C3, exhibit potent Minimum Inhibitory Concentration (MIC) values and clear selectivity towards Gram-positive bacteria in solution, resulting in inhibitory activity at exceptionally low concentrations (0.19–0.0015 μg/mL). By integrating these barbiturates within polymeric matrices, an advanced antibacterial polymer was obtained. This novel material facilitates the dual benefit of detecting Gram-negative bacterial colonies via colorimetric alterations, while simultaneously providing a broad-spectrum antibacterial approach, effective against both Gram-positive and Gram-negative bacteria. The potential of these barbiturate-enhanced polymers is substantial, not least because of their cost-effective nature. Their inherent feature of enabling naked-eye selective alterations, positions them as an efficient, onsite tool for monitoring contamination by E. coli and P. aeruginosa in clinical environments. Thus, these polymers open a new horizon for innovative, rapid, and low-cost strategies in microbial contamination control and patient safety.
Advances in Antimicrobial Applications of Ag, Cu, and AgCu Nanoparticle-Doped Polymeric Composite Materials
Publication . Galhano, Joana; Capelo-Martinez, José Luis; Lorenzo, Julia; Lodeiro, Carlos; Oliveira, Elisabete; Faculdade de Ciências e Tecnologia (FCT); ACS - American Chemical Society
The growing challenge of antimicrobial resistance (AMR) has driven the search for alternative strategies to conventional antibiotics, with metallic nanoparticles (NPs), particularly silver (Ag), copper (Cu), and their bimetallic hybrids (AgCu), emerging as promising candidates. These nanoparticles exhibit strong, multifaceted antimicrobial activity and, when integrated into polymeric matrices, form composite materials that offer enhanced stability, controlled release, and broad applicability across healthcare, food safety, and industrial sectors. This review highlights the major synthetic routes for the production of Ag, Cu, and AgCu nanoparticles and discusses their integration into polymeric systems. Furthermore, the antimicrobial mechanisms of these nanomaterials are explored. Finally, the review emphasizes the potential of these nanocomposites to serve as next-generation antimicrobial surfaces, wound dressings, and functional materials, while addressing key synthesis challenges and proposing future research directions to optimize their performance and expand their applications.
Fluorescent polymers for environmental monitoring
Publication . Galhano, Joana; Kurutos, Atanas; Dobrikov, Georgi M.; Duarte, Maria Paula; Santos, Hugo M.; Capelo-Martínez, Jose Luis; Lodeiro, Carlos; Oliveira, Elisabete; DQ - Departamento de Química; Faculdade de Ciências e Tecnologia (FCT); MEtRICS - Centro de Engenharia Mecânica e Sustentabilidade de Recursos; Elsevier
Monitoring Hg2+ levels in aqueous environments is crucial to assess the potential methylmercury contamination via bacterial conversion, however, existing methods often require extensive sample treatment and expensive equipment. To mitigate this issue, this study examines the synthesis and application of three naphthalimide-based compounds, with significant fluorescent and solvatochromic behavior (C1, C2, and C3). Compounds C1 and C2 demonstrated a strong affinity for Hg2+ metal ions, with C2 showing selectivity and a strong antibacterial profile, particularly against S. aureus (MIC50 (C2) = 0.01 µg/mL). Moreover, these compounds were incorporated into three polymeric matrices, namely polyvinyl chloride (PVC), poly (methyl methacrylate-co-methacrylic acid) (PMMMA), and Starch, allowing for the development of solid-support sensors/surfaces with a strong antibacterial profile, highlighting the inherent dual-functionality of the compounds. Interestingly, the C2-doped Starch biopolymer detected low concentrations of Hg2+ ions, such as 23 nM in tap water (value within the WHO standards for drinking water), through a rapid spectroscopic evaluation without sample treatment. This biopolymer was generated via a sustainable, green-chemistry-oriented, temperature-dependent water/Starch synthetic route, without the addition of plasticizers and any associated ecotoxicity. The study used sustainable methods for environmental monitoring and antibacterial applications, advancing material science to offer effective, accessible, and eco-friendly solutions for detecting and mitigating mercury pollution and bacterial contaminations, enhancing environmental and health safety.
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2022.09495.BD