Associated Laboratory for Green Chemistry - Clean Technologies and Processes

Funder

Organizational Unit

Publications

Biocompatible oligo-oxazoline crosslinkers: Towards advanced chitosans for controlled dug release

Publication . Lopes, Mafalda; Restani, Rita; Carvalho, Marco António Paulo de; Correia, I.J.; Ricardo, Ana Aguiar; Bonifácio, Vasco

Chitosan, a natural and abundant biopolymer has been long explored as a biocompatible material for the preparation of drug delivery devices. This strategy has been mostly accomplished using chemically crosslinked chitosan leading to more stable scaffolds. However, crosslinking has been shown to reduce both biocompatibility and swelling. In this work chitosan was crosslinked with novel biocompatible crosslinkers, based on oligo-oxazolines and glycidyl methacrylate copolymers, leading to patches with a very high swelling capacity. Dexamethasone therapeutics is strongly enhanced by a controlled release administration. This study shows that oligo-oxazoline-crosslinked chitosan is a suitable biomaterial for loading and controlled release of dexamethasone.

2021Journal article

Open access

Antimicrobial and Antibiofilm Properties of Fluorinated Polymers with Embedded Functionalized Nanodiamonds

Publication . Nunes-Pereira, João; Costa, Pedro; Fernandes, Liliana; Carvalho, Estela O.; Fernandes, Margarida M.; Carabineiro, S.A.C.; Buijnsters, Josephus; Rial Tubio, Carmen; Lanceros-Mendez, Senentxu

Environmentally resilient antimicrobial coatings are becoming increasingly required for a wide range of applications. For this purpose, nanocomposite thin films of poly(vinylidene fluoride) (PVDF) filled with several types of functionalized nanodiamonds (NDs) were processed by solvent casting. The effects of ND inclusion and functionalization in their morphological, structural, optical, thermal, and electrical properties were evaluated taking into account the type of the nanofiller and a concentration up to 2 wt %. The morphology, structure, and thermal features of the polymer matrix are governed by the processing conditions, and no noticeable changes occurred due to the presence of the ND fillers. The polymer crystallized mainly in the α phase with a crystallinity of ≈60%. In turn, the optical transmittance from 200 to 800 nm and the dielectric constant effectively depended on the ND type and content. The inclusion of the ND particles effectively provided antimicrobial properties to the films, which depended on the ND functionalization. This study thus shows that the incorporation of functionalized NDs into PVDF allows the development of antimicrobial coatings with tailorable optical and dielectric properties, which could be of great importance to face nowadays pandemic crisis scenario.

2020Journal article

Restricted access

The role of ayahuasca in cell viability and oxidative stress in gastric adenocarcinoma cell line

Publication . Gonçalves, Joana; Cascalheira, José; Valentão, Patrícia; Luís, Ângelo; Gallardo, Eugenia; Duarte, Ana Paula

Ayahuasca, a psychoactive beverage native to the Amazon, originally derived from Banisteriopsis caapi stem scrapings and Psychotria viridis leaves, exhibits hallucinogenic properties due to N,Ndimethyltryptamine. When combined with β-carbolines, it enters the bloodstream and central nervous system, inhibiting monoamine oxidase-A. Over time, therapeutic effects have been associated to ayahuasca consumption. This study assessed the impact of extracts from three plant decoctions used in ayahuasca preparation on the gastric adenocarcinoma cell line (AGS). MTT reduction assays selected B. caapi, Mimosa hostilis, and Peganum harmala samples as most effective. Lactate dehydrogenase activity evaluated membrane integrity loss, while oxidative stress induction was measured using dihydroethidium and 2′,7′-dichlorodihydrofluorescein diacetate probes. Results revealed apoptosis induction in AGS Ucells, with all three samples significantly reducing oxidative stress.

2024-07-04Journal article

Restricted access

Antimicrobial and antitumor activity of S-methyl dithiocarbazate Schiff base zinc(II) complexes

Publication . Gomes, Filipa Ramilo; Addis, Yemataw; Tekamo, Israel; Cavaco, Isabel; Campos, Débora L.; Pavan, Fernando R.; Gomes, Clara S.B.; Brito, Vanessa; Santos, Adriana O.; Domingues, F.C.; Luís, Ângelo; Marques, M. Matilde; Pessoa, João Costa; Ferreira, Susana; Silvestre, Samuel; Correia, Isabel

Schiff bases (SB) obtained from S-methyl dithiocarbazate and aromatic aldehydes: salicylaldehyde (H2L1), o-vanillin (H2L2), pyridoxal (H2L3) and 2,6-diformyl-4-methylphenol (H3L4), and their corresponding Zn(II)-complexes (1-4), are synthesized. All compounds are characterized by elemental analyses, infrared, UV-Vis, nuclear magnetic resonance spectroscopy and mass spectrometry. The structures of H2L2 and [Zn2(L1)2(H2O)(DMF)] (1a) (DMF = dimethylformamide) are solved by single crystal X-ray diffraction. The SB coordinates the metal center through the Ophenolate, Nimine and Sthiolate atoms. The radical scavenging activity is tested using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, with all ligand precursors showing IC50 values ~40 μM. Cytotoxicity studies with several tumor cell lines (PC-3, MCF-7 and Caco-2) as well as a non-tumoral cell line (NHDF) are reported. Interestingly, 1 has relevant and selective antiproliferative effect against Caco-2 cells (IC50 = 9.1 μM). Their antimicrobial activity is evaluated in five bacterial strains (Klebsiella pneumoniae, Acinetobacter baumannii, Listeria monocytogenes, Pseudomonas aeruginosa and Staphylococcus aureus) and two yeast strains (Candida albicans and Candida tropicalis) with some compounds showing bacteriostatic and fungicidal activity. The minimal inhibitory concentration (MIC90) of HnL against Mycobacterium tuberculosis is also reported, with H2L2 and H3L4 showing very high activity (MIC90 < 0.6 μg/mL). The ability of the compounds to bind bovine serum albumin (BSA) and DNA is evaluated for H3L4 and [Zn2(L4)(CH3COO)] (4), both showing high binding constants to BSA (ca. 106 M-1) and ability to bind DNA. Overall, the reported compounds show relevant antitumor and antimicrobial properties, our data indicating they may be promising compounds in several fields of medicinal chemistry.

2021Journal article

Restricted access

Multifunctional targeted solid lipid nanoparticles for combined photothermal therapy and chemotherapy of breast cancer

Publication . Granja, Andreia; Lima-Sousa, Rita; Alves, Cátia; de Melo-Diogo, Duarte; Nunes, Cláudia; Sousa, Célia T.; Correia, I.J.; Reis, Salette

Photothermal therapy has emerged as a new promising strategy for the management of cancer, either alone or combined with other therapeutics, such as chemotherapy. The use of nanoparticles for multimodal therapy can improve treatment performance and reduce drug doses and associated side effects. Here we propose the development of a novel multifunctional nanosystem based on solid lipid nanoparticles co-loaded with gold nanorods and mitoxantrone and functionalized with folic acid for dual photothermal therapy and chemotherapy of breast cancer. Nanoparticles were produced using an economically affordable method and presented suitable physicochemical properties for tumor passive accumulation. Upon Near-Infrared irradiation (808 nm, 1.7 W cm -2, 5 min), nanoparticles could effectively mediate a temperature increase of >20 ◦C. Moreover, exposure to light resulted in an enhanced release of Mitoxantrone. Furthermore, nanoparticles were non-hemolytic and well tolerated by healthy cells even at high concentrations. The active targeting strategy was found to be successful, as shown by the greater accumulation of the functionalized nanoparticles in MCF-7 cells. Finally, the combined effects of chemotherapy, light-induced drug release and photothermal therapy significantly enhanced breast cancer cell death. Overall, these results demonstrate that the developed lipid nanosystem is an efficient vehicle for breast cancer multimodal therapy.

2023-04-28Journal article

Open access