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Publications

Publications by Carla Queirós

2022

Synthesis of Novel Diketopyrrolopyrrole-Rhodamine Conjugates and Their Ability for Sensing Cu2+ and Li+

Authors
Queiros, C; Almodovar, VAS; Martins, F; Leite, A; Tome, AC; Silva, AMG;

Publication
MOLECULES

Abstract
The search for accurate and sensitive methods to detect chemical substances, namely cations and anions, is urgent and widely sought due to the enormous impact that some of these chemical species have on human health and on the environment. Here, we present a new platform for the efficient sensing of Cu2+ and Li+ cations. For this purpose, two novel photoactive diketopyrrolopyrrole-rhodamine conjugates were synthesized through the condensation of a diketopyrrolopyrrole dicarbaldehyde with rhodamine B hydrazide. The resulting chemosensors 1 and 2, bearing one or two rhodamine hydrazide moieties, respectively, were characterized by H-1 and C-13 NMR and high-resolution mass spectrometry, and their photophysical and ion-responsive behaviours were investigated via absorption and fluorescence measurements. Chemosensors 1 and 2 displayed a rapid colorimetric response upon the addition of Cu2+, with a remarkable increase in the absorbance and fluorescence intensities. The addition of other metal ions caused no significant effects. Moreover, the resulting chemosensor-Cu2+ complexes revealed to be good probes for the sensing of Li+ with reversibility and low detection limits. The recognition ability of the new chemosensors was investigated by absorption and fluorescence titrations and competitive studies.

2022

Sustainability Prize 1 Green Endoscopy to reduce CO2e generated by endoscopic waste - the GECO(2e) interventional study

Authors
Neves, JAC; Roseira, J; Queiros, P; de Sousa, HT; Pellino, G; Cunha, M;

Publication
BRITISH JOURNAL OF SURGERY

Abstract
Abstract Aims Endoscopy is healthcare's third-largest waste-generating procedure. This study aimed to measure a single unit's waste carbon footprint and to perform a pioneer evaluation applying the principles of green endoscopy towards a more sustainable unit. Methods This was a 3-stage, prospective study. Stage 1: 4-week observational audit, during which daily endoscopic waste (landfill, biohazard) was weighed. Stage 2: 1-week intervention with presentation of retrieved data and education of the team towards waste handling. Recycling bins were placed in endoscopy rooms, and landfill and biohazard bins were relocated. Stage 3: 4-week post-interventional period, during which daily endoscopic waste was weighed. An engineer-calibrated scale was used. Equivalence of 1kg of landfill waste to 1kg carbon dioxide equivalent (CO2e) and 1kg of biohazard waste to 3kgCO2e was applied. Paired samples T-tests were used for comparisons before and after the intervention. The opinion of the staff was collected. Results Total waste and biohazard waste were diminished by 12.2% (p=0.166) and 41.4% (p=0.010), respectively, whereas landfill waste (p=0.059) and recycling waste increased (paper: p=0.001; plastic: p=0.007). In terms of CO2e, a total decrease of 31.6% (138.8kgCO2e) was found (mean kgCO2e 109.7 vs 74.9, pre- vs post-intervention, p=0.018). Mean endoscopy load was similar (46.2 vs 44.5, p=0.275). The endoscopy unit may achieve an estimated annual reduction of 1665.6kgCO2e. The personnel agreed “the project did not disturb daily work”. Conclusions In this interventional study applying green endoscopy principles to a real-world scenario, biohazard waste reduction and daily recycling were achieved, without compromising endoscopy productivity.

2021

Amination of Cyclohexanol over a Ni-Based Catalyst - Part II: Catalyst Stability and Reaction Pathway

Authors
Churro, R; Mendes, F; Araujo, P; Ribeiro, MF; Madeira, LM;

Publication
CHEMICAL ENGINEERING & TECHNOLOGY

Abstract
Ni-based catalysts present a highly interesting performance for the reductive amination of cyclohexanol (CHOL). The stability of a commercial Ni-based catalyst was evaluated and a high stability over the tested time-on-stream (TOS) was observed. The reaction network was evaluated by analysis of selectivity profiles as a function of CHOL conversion. The formation of cyclohexylamine (CHA) was found to be consistent with the proposed borrowing hydrogen method (BHM). The formation of heavy-end (HE) by-products also follows the BHM pathway as parallel reaction. The effect of individual molar proportions of NH3 and H-2 was evaluated. It was found that when H-2 is present in a high excess, side reactions were favored, but its presence is mandatory towards keeping the catalyst active.

2021

Reversible Protonation of Porphyrinic Metal-Organic Frameworks Embedded in Nanoporous Polydimethylsiloxane for Colorimetric Sensing

Authors
Sousaraei, A; Queiros, C; Moscoso, FG; Silva, AMG; Lopes Costa, T; Pedrosa, JM; Cunha Silva, L; Cabanillas Gonzalez, J;

Publication
ADVANCED MATERIALS INTERFACES

Abstract
A fast and reversible switch between the neutral and protonated porphyrin forms inside a pliable porphyrinic metal-organic framework (MOF), enabled by reversible structural deformation is unveiled. This phenomenon is applied for the development of MOF-polymer porous composites to reveal biogenic amines by color changes.

2021

Synthesis, characterization, and cellular investigations of porphyrin-and chlorin-indomethacin conjugates for photodynamic therapy of cancer

Authors
Almeida, J; Zhang, GY; Wang, MD; Queiros, C; Cerqueira, AFR; Tome, AC; Barone, G; Vicente, MGH; Hey Hawkins, E; Silva, AMG; Rangel, M;

Publication
ORGANIC & BIOMOLECULAR CHEMISTRY

Abstract
Indomethacin is a potent non-steroidal anti-inflammatory drug (NSAID) with a strong selective inhibitor activity towards cyclooxygenase-2 (COX-2), an enzyme that is highly overexpressed in various tumour cells, being involved in tumourigenesis. Concomitantly, porphyrins have gained much attention as promising photosensitizers (PSs) for the non-invasive photodynamic therapy (PDT) of cancer. Herein, we report the design, and determine the singlet oxygen generation capacity and in vitro cellular toxicity of porphyrin.- and chlorin-indomethacin conjugates (P2-Ind and C2-Ind). Both the conjugates were obtained in high yields and were characterized by H-1, F-19 and C-13 NMR as well as by high resolution mass spectrometry. The singlet oxygen generation properties were assessed by the 1,3-diphenylisobenzofuran singlet oxygen trap method, which showed that C2 and C2-Ind are the best singlet oxygen photosensitizers. in addition, it was found that the presence of indomethacin did not influence the singlet oxygen generation of porphyrin or chlorin. Cytotoxicity studies of the conjugate in human HEp2 cells revealed that the porphyrin ... and chlorin- indomethacin conjugates have similar dark cytotoxicities, while chlorin C2 was shown to be the most phototoxic. Despite having lower cellular uptake than C2-Ind after 24 hours, chlorin C2 had a broad localization in HEp2 cells while the chlorin-indomethacin conjugate C2-Ind could be detected in the form of small aggregates. DFT calculations were performed to shed light on the reaction energy involved in the formation of the indomethacin conjugates and to compare the relative stability of selected isomers in solution. Moreover, the calculated energy of their first excited triplet state structures confirmed their use as suitable photosensitizers to generate singlet oxygen for PDT.

2021

Synthesis of a highly emissive carboxylated pyrrolidine-fused chlorin for optical sensing of TATP vapours

Authors
Vargas, AP; Almeida, J; Gamez, F; Roales, J; Queiros, C; Rangel, M; Lopes Costa, T; Silva, AMG; Pedrosa, JM;

Publication
DYES AND PIGMENTS

Abstract
We describe the synthesis and characterization of a new N-methylpyrrolidine-fused meso-tetracarboxyphenyl-chlorin with highly emissive features. The synthetic approach to obtain the fluorescent chlorin involves the microwave-assisted synthesis of meso-tetrakis (4-methoxycarbonylphenyl)porphyrin, followed by a 1,3-dipolar cycloaddition reaction of this porphyrin with azomethine ylide and, finally, ester hydrolysis under basic conditions. The incorporation and anchoring of the chlorin to a nanostructured porous TiO2 matrix is achieved and optimized for its use as a fluorescent sensor. In particular, we found an efficient detection of the explosive triacetone triperoxide (TATP) in the gas phase. The optical response after analyte exposure is selective and fast, with response time t(50) values of less than 10 min under exposure to TATP saturated vapours.

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