Helena Oliveira

Helena Oliveira
University of Aveiro | UA · Centre for Environmental and Marine Studies (CESAM)

PhD

About

203
Publications
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3,850
Citations

Publications

Publications (203)
Article
DNA chains with sequential guanine (G) repeats can lead to the formation of G-quadruplexes (G4), which are found in functional DNA and RNA regions like telomeres and oncogene promoters. The development of molecules with adequate structural features to selectively stabilize G4 structures can counteract cell immortality, highly described for cancer c...
Article
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In this work, hybrid materials within the polydimethylsiloxane–silica (PDMS–SiO2) system, synthesized via the sol–gel method, were developed and characterized for their potential to incorporate and release the bioactive compound resveratrol (RES). RES was incorporated into the materials with a high loading efficiency (>75%) using the rotary evapora...
Article
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Responsive magnetic nanomaterials offer significant advantages for innovative therapies, for instance, in cancer treatments that exploit on‐demand delivery on alternating magnetic field (AMF) stimulus. In this work, biocompatible magnetic bionanocomposite films are fabricated from chitosan by film casting with incorporation of magnetite nanoparticl...
Article
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Atmospheric particulate matter (PM) with diameters below 10 µm (PM10) may enter the lungs through inhalation and are linked to various negative health consequences. Emergent evidence emphasizes the significance of cell metabolism as a sensitive target of PM exposure. However, the current understanding of the relationship between PM composition, con...
Article
3D bioprinting is a versatile technique that allows the fabrication of living tissue analogs through the layer-by-layer deposition of cell-laden biomaterials, viz. bioinks. In this work, composite alginate hydrogel-based bioinks reinforced with curcumin-loaded particles of cellulose esters (CEpCUR) and laden with human keratinocytes (HaCaT) are dev...
Article
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Antimicrobial photodynamic therapy (aPDT) is a potent tool to surpass the global rise of antimicrobial resistance; still, the effective topical administration of photosensitizers remains a challenge. Biopolymer-based adhesive films can safely extend the residence time of photosensitizers. However, their wide application is narrowed by their limited...
Article
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Lycopene is a carotenoid with potential use in the treatment of chronic illnesses. Here, different formulations of lycopene were studied: lycopene-rich extract from red guava (LEG), purified lycopene from red guava (LPG) and a self-emulsifying drug delivery system loaded with LPG (nanoLPG). The effects of administering orally various doses of LEG t...
Article
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Melanoma incidence, a type of skin cancer, has been increasing worldwide. There is a strong need to develop new therapeutic strategies to improve melanoma treatment. Morin is a bioflavonoid with the potential for use in the treatment of cancer, including melanoma. However, therapeutic applications of morin are restrained owing to its low aqueous so...
Article
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People spend most of their time indoors, particularly in their houses where daily activities are carried out, enhancing particulate matter (PM) emissions with consequent adverse health impacts. This study intended to appraise the toxicological and mutagenic responses of particulate matter with a diameter less than 10 μm (PM10) released from cooking...
Article
The present study aimed to evaluate the reprotoxicity of environmental (0.25μg.L-1) and supra-environmental (25μg.L-1 and 250μg.L-1) levels of silver nanoparticles (Ag NP) on the Pacific oyster (Magallana gigas), by determining sperm quality. For that, we evaluated sperm motility, mitochondrial function and oxidative stress. To determine whether th...
Article
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Knowledge regarding genome size allows us to infer relationships between taxa, address questions related to systematics and contribute to biodiversity studies. However, currently, less than 3% of the described Pteridophyta species have genome size estimates reported in databases, and only around one third of these are tropical species, although the...
Article
Titanium dioxide nanoparticles (TiO2 NP) were reported to be reprotoxic in humans and fish. However, the effects of these NP on the reproduction of marine bivalves, namely oysters, remain unknown. Thus, a short-term (1 h) direct exposure of sperm of the Pacific oyster (Crassostrea gigas) to two TiO2 NP concentrations (1 and 10 mg.L-1) was performed...
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Calendula is one of the most taxonomically complex genera within the Asteraceae family due to hybridization, polyploidization events, and production of a highly variable morphology of the achenes. Considering the complexity of Calendula, this study was conducted to extend the understanding of the relationships between SW Mediterranean taxa, and ass...
Article
The development of suitable bioinks is an important research topic in the field of three-dimensional (3D) bioprinting. Herein, novel hydrogel-based bioinks composed of nanofibrillated cellulose (NFC) and gellan gum (GG) in different NFC/GG mass proportions (90:10, 80:20, 70:30, and 60:40) were developed and characterized. The increase in the conten...
Article
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Recent studies have shown that the addition of non-viable microbial biomass or their components (postbiotics) to fish feed can modulate the gut microbiome and positively influence fish health in aquaculture systems. However, no information was hitherto available on the use of non-viable microbial biomass to manipulate aquaculture bacterioplankton c...
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Melanoma is an aggressive form of skin cancer with a high prevalence in the population. An early diagnosis is crucial to cure this disease. Still, when this is not possible, combining potent pharmacological agents and effective drug delivery systems is essential to achieve optimal treatment and improve patients’ quality of life. Nanotechnology appl...
Article
The aim of this study is to prepare dissolvable biopolymeric microneedle (MN) patches comprised solely of sodium carboxymethylcellulose (CMC), a water‐soluble cellulose derivative with good film‐forming ability, by micromoulding technology for the transdermal delivery of diclofenac sodium salt (DCF). The microneedles with ca. 456 μm in height displ...
Article
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Exposure to atmospheric fine particulate matter (PM2.5) is currently recognized as a leading cause and/or a serious aggravating factor of several respiratory diseases, such as chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, asthma, and lung cancer. Notably, pulmonary-altered metabolism has emerged as an important hallmark of those...
Presentation
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Cytotoxic effects of wildfire ashes on skin cells using in-vitro bioassays
Article
Breast cancer represents the most incident cancer in women. Surgery, chemotherapy, radiation therapy, and hormone therapy remain the main treatment for this type of cancer. However, increasing resistance to anti-cancer drugs through poor response for some types of breast cancer to treatments highlights the need to develop new therapeutic agents to...
Article
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In this study, alginate nanocomposite hydrogel bioinks reinforced with lysozyme nanofibers (LNFs) were developed. Alginate-LNF (A-LNF) suspensions with different LNF contents (1, 5 and 10 wt.%) were prepared and pre-crosslinked with 0.5% (w/v) CaCl2 to formulate A-LNF inks. These inks exhibit proper shear-thinning behavior and good recovery propert...
Article
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The unique physicochemical properties of silver nanoparticles (AgNPs) make them useful in a wide range of sectors, increasing their propensity for human exposure, as well as the need for thorough toxicological assessment. The biodistribution of silver, hematological parameters and GSH/GSSG levels in the lung and liver were studied in mice that were...
Article
Particulate matter emissions (PM10) from the combustion, in a residential stove, of two commercial brands of certified (ENplus A1) pellets, a non-certified brand and laboratory made pellets of acacia were tested for their ability to induce ecotoxic, cytotoxic, and mutagenic responses in unicellular organisms and a human cell line. Ecotoxicity was e...
Article
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Graphene-related two-dimensional nanomaterials possess very technically promising characteristics, but gaps exist regarding their potential adverse health effects. Based on their nano-thickness and lateral micron dimensions, nanoplates exhibit particular aerodynamic properties, including respirability. To develop a lung-focused, in vitro/in vivo sc...
Article
Nanoparticles (NP) are potentially reprotoxic, which may compromise the success of populations. However, the reprotoxicity of NP is still scarcely addressed in marine fish. Therefore, we evaluated the impacts of environmentally relevant and supra environmental concentrations of titanium dioxide (TiO2: 10 to 10,000 μg·L⁻¹) and silver NP (Ag: 0.25 to...
Article
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Melanoma is a drug-resistant cancer, representing a serious challenge in cancer treatment. Dacarbazine (DTIC) is the standard drug in metastatic melanoma treatment, despite the poor results. Hyperthermia has been proven to potentiate chemotherapy. Hence, this work analyzed the combined action of hyperthermia and DTIC on A375 and MNT-1 cell lines. F...
Article
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Upconversion nanoparticles (UCNPs) have attracted considerable attention owing to their unique photophysical properties. Their utilization in biomedical applications depends on the understanding of their transformations under physiological conditions and their potential toxicity. In this study, NaYF4:Yb,Er UCNPs, widely used for luminescence and ph...
Article
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Burning vegetative debris is a worldwide long-standing practice. The current study was designed to examine the cytotoxicity and mutagenicity of particulate matter with an aerodynamic diameter below 10 µm (PM10) released from the burning of pruning residues common in Portugal and other countries of the Mediterranean region. Field measurements were c...
Article
The critical scenario of antimicrobial resistance to antibiotics highlights the need for improved therapeutics and/or formulations. Herein, we demonstrate that deep eutectic solvents (DES) formulations are very promising to remarkably improve the solubility, stability and therapeutic efficacy of antibiotics, such as ciprofloxacin. DES aqueous solut...
Article
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BACKGROUND Natural products are currently in the spotlight due to the increasing awareness of consumers. Among these products is phycocyanin (C‐PC), a blue colorant that can be extracted from cyanobacteria – a poorly explored feedstock – and applied in several fields, due to its argued health benefits. Arthropira (previously called Spirulina) is th...
Article
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Melanoma is the deadliest form of skin cancer, and its incidence has alarmingly increased in the last few decades, creating a need for novel treatment approaches. Thus, we evaluated the combinatorial effect of doxorubicin (DOX) and hyperthermia on A375 and MNT-1 human melanoma cell lines. Cells were treated with DOX for 24, 48, and 72 h and their v...
Article
Fridericia chica (Bonpl.) L.G. Lohmann (synonym Arrabidaea chica Verlot) is widely used in Brazilian folk medicine. Considering overcoming pitfalls of scaling up production of plant extracts, herein the effects of N2 atmosphere for extract spray-drying process is reported. Samples were monitored by in vitro antioxidant activity and microbiological...
Article
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Lead (Pb) soil contamination remains a major ecological challenge. Zygophyllum fabago is a candidate for the Pb phytostabilisation of mining tailings; nevertheless, the cytogenotoxic effects of low doses of Pb on this species are still unknown. Therefore, Z. fabago seeds collected from non-mining (NM) and mining (M) areas were exposed to 0, 5 and 2...
Article
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Magnetic nanoparticles (NP), such as magnetite, have been the subject of research for application in the biomedical field, especially in Magnetic Hyperthermia Therapy (MHT), a promising technique for cancer therapy. NP are often coated with different compounds such as natural or synthetic polymers to protect them from oxidation and enhance their co...
Article
Hyperspectral microscopy is an intriguing technique combining spectroscopy with optical microscopy that can be used to simultaneously obtain spectral and spatial information. The relevance of hyperspectral imaging in biomedical applications such as the monitoring of bioimaging agents, the identification of pathogens and cancerous cells, and the cel...
Article
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3D printing emerged as a potential game-changer in the field of biomedical engineering. Robocasting in particular has shown excellent capability to produce custom-sized porous scaffolds from pastes with suitable viscoelastic properties. The materials and respective processing methods developed so far still need further improvements in order to obta...
Article
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Cellulose nanocrystals (CNCs) are elongated biobased nanostructures with unique characteristics that can be explored as nanosystems in cancer treatment. Herein, the synthesis, characterization, and cellular uptake on folate receptor (FR)-positive breast cancer cells of nanosystems based on CNCs and a chitosan (CS) derivative are investigated. The p...
Article
The emergence of multi-drug resistant bacteria and limitations on cancer treatment represent two important challenges in modern medicine. Biological compounds have been explored with a particular focus on venoms. Although they can be lethal or cause considerable damage to humans, venom is also a source rich in components with high therapeutic poten...
Article
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New agents are demanded to increase the therapeutic options for osteosarcoma (OS). Although OS is the most common bone cancer in children and adolescents, it is considered a rare disorder. Therefore, finding adjuvant drugs has potential to advance therapy for this disease. In this study, 3′,4′-dihydroxyflavonol (DiOHF) was investigated to assess th...
Article
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Copper chrome arsenate (CCA) water-borne solution used to be widely used to make timber highly resistant to pests and fungi, in particular, wood products designed for outdoor use. Nowadays, CCA is a restricted chemical product in most countries, since potential environmental and health risks were reported due to dermal contact with CCA residues fro...
Article
Wildfires are a complex environmental problem worldwide. The ashes produced during the fire bear metals and PAHs with high toxicity and environmental persistence. These are mobilized into downhill waterbodies, where they can impair water quality and human health. In this context, the present study aimed at assessing the toxicity of mimicked wildfir...
Preprint
Full-text available
Nanographene oxide (nGO)-mediated hyperthermia has been increasingly investigated as a localised, minimally invasive anticancer therapeutic approach. Near InfraRed (NIR) light irradiation for inducing hyperthermia is particularly attractive, because biological systems mostly lack chromophores that absorb in this spectral window, facilitating the se...
Article
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Chemotherapy has limited success in the treatment of malignant melanoma due to fast development of drug resistance and the low bioavailability of chemotherapeutic drugs. Resveratrol (RES) is a natural polyphenol with recognized preventive and therapeutic anti-cancer properties. However, poor RES solubility hampers its bioactivity, thus creating a d...
Research Proposal
Full-text available
Nanotechnology has gained growing importance in diverse fields of science, medicine, economy and industry. Nevertheless, the generalized use of nanomaterials (NM) lead to their release (direct or indirect) to the environment and consequent interaction with natural systems. Several studies have highlighted the potential toxicity of nanomaterials for...
Article
Particulate matter with aerodynamic diameter < 10 μm (PM10) was collected, indoors and outdoors, when wood burning appliances (open fireplace and woodstove) were in operation. The PM10 ecotoxicity was assessed with the Vibrio fischeri bioluminescence inhibition assay, while the cytotoxicity was evaluated by the WST-8 and lactate dehydrogenase (LDH)...
Article
Full-text available
Upconversion nanoparticles (UCNPs), consisting of NaYF 4 doped with 18% Yb and 2% Er, were coated with microporous silica shells with thickness values of 7 ± 2 and 21 ± 3 nm. Subsequently, the negatively charged particles were functionalized with N -(6-aminohexyl)-3-aminopropyltrimethoxysilane (AHAPS), which provide a positive charge to the nanopar...
Article
Full-text available
The respiratory tract is the route of entry for accidentally inhaled AgNPs, which can reach the lungs and redistribute to other main organs through systemic circulation. In the present work, we aimed to evaluate silver biodistribution and biological effects after 1 or 2 intratracheal instillations (IT) of two differently sized PVP-coated AgNPs (5 a...
Article
Full-text available
Antibacterial multi-layered patches composed of an oxidized bacterial cellulose (OBC) membrane loaded with dexpanthenol (DEX) and coated with several chitosan (CH) and alginate (ALG) layers were fabricated by spin-assisted layer-by-layer (LbL) assembly. Four patches with a distinct number of layers (5, 11, 17, and 21) were prepared. These nanostruc...
Preprint
Full-text available
Upconversion nanoparticles (UCNP) consisting of NaYF₄ doped with 18% Yb and 2% Er were coated with microporous silica shells of 7±2 nm and 21±3 nm thickness. Subsequently, the initially negatively charged particles were optionally functionalized with N-(6-aminohexyl)-aminopropyltrimethoxysilane (AHAPS), providing a positive charge onto the nanopart...
Article
Full-text available
Urea, the main nitrogenous waste product of protein metabolism, is eliminated almost exclusively by the kidney, and hence, displays considerable clinical significance in the assessment of kidney disorders. The aim of this study is to prepare and investigate the potential of swellable cross‐linked gelatin methacryloyl (c‐GelMA) microneedles (MNs) as...
Article
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Plant-derived pentacyclic triterpenic acids (TAs) have gained increasing attention due to their multiple biological activities. Betulinic acid (BA) and ursolic acid (UA) modulate diverse pathways in carcinogenesis, offering increased changes of success in refractory cancers, such as triple negative breast cancer (TNBC). The present work aimed to as...
Article
The aim of the present study was to develop innovative patches for dermo-cosmetic applications based on dissolvable hyaluronic acid (HA) microneedles (MNs) combined with bacterial nanocellulose (BC) as the back layer. HA was employed as an active biomacromolecule, with hydrating and regenerative properties and volumizing effect, whereas BC was used...
Article
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This study employed NMR metabolomics to characterize macrophage responses to subtoxic concentrations of silver nanoparticles (AgNPs ca. 30 nm) and ionic silver (Ag⁺), with a view to further elucidate their immunomodulatory activity at the cell metabolism level. Exposure to AgNPs caused RAW 264.7 macrophages to decrease intracellular glucose utiliza...
Article
The present study reports the fabrication of dissolvable microneedle (MN) patches using pullulan (PL), a water-soluble polysaccharide with excellent film-forming ability, for the transdermal administration of insulin, envisioning the non-invasive treatment of diabetes. PL MNs patches were successfully prepared by micromolding and revealed good ther...
Article
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Nanostructured patches composed of bacterial nanocellulose (BNC), hyaluronic acid (HA) and diclofenac (DCF) were developed, envisioning the treatment of aphthous stomatitis. Freestanding patches were prepared via diffusion of aqueous solutions of HA and DCF, with different concentrations of DCF, into the wet BNC three-dimensional porous network. Th...
Article
Full-text available
Gold nanoparticles (AuNPs) are one of the most studied nanosystems with great potential for biomedical applications, including cancer therapy. Although some gold-based systems have been described, the use of green and faster methods that allow the control of their properties is of prime importance. Thus, the present study reports a one-minute micro...
Article
Sustainably made, flexible and biocompatible composites, having environmentally friendly compositions and multifunctional capabilities, are promising materials for several emerging biomedical applications. Here, the development of flexible and multifunctional chitosan-based bionanocomposites with a mixed reduced graphene oxide-iron oxide (rGO-Fe3-x...