Paula Parreira

• PhD in Biomedical Engineering
• Researcher at INEB/i3S

Helicobacter pylori chronic infection is the highest risk factor for the development of gastric cancer, being this Gram‐negative bacterium classified as carcinogenic. The mounting resistance of H. pylori to antibiotics calls for innovative therapeutic strategies. Here, the proof‐of‐concept studies that support the development of a “trojan horse” th...

Surface bioconjugation of antimicrobial peptides (AMP) onto nanoparticles (AMP-NP) is a complex, multistep, and time-consuming task. Herein, a microfluidic system for the one-pot production of AMP-NP was developed. Norbornene-modified chitosan was used for NP production (NorChit-NP), and thiolated-AMP was grafted on their surface via thiol–norborne...

Self-assembled monolayers (SAMs) based on peptides represent a reproducible platform for screening and studying peptide functions and facilitating their translation into multidisciplinary applications.

Background The World Health Organization has identified Helicobacter pylori , a Gram‐negative bacterium responsible for several gastric disorders, as one of the pathogenic bacteria that requires newer non‐antibiotic approaches for its management. We previously demonstrated that nanostructured lipid carriers (NLC) loaded with docosahexaenoic acid (D...

It is key to fight bacterial adhesion to prevent biofilm establishment on biomaterials. Surface immobilization of antimicrobial peptides (AMP) is a promising strategy to avoid bacterial colonization. This work aimed to investigate whether the direct surface immobilization of Dhvar5, an AMP with head-to-tail amphipathicity, would improve the antimic...

The use of human Mesenchymal Stem Cells (hMSC) as therapeutic agents for advanced clinical therapies relies on their in vitro expansion. Over the last years, several efforts have been made to optimize hMSC culture protocols, namely by mimicking the cell physiological microenvironment, which strongly relies on signals provided by the extracellular m...

The major risk factor associated with the development of gastric cancer is chronic infection with Helicobacter pylori. The available treatments, based on a cocktail of antibiotics, fail in up to 40% of patients and disrupt their gut microbiota. The potential of blank nanostructured lipid carriers (NLC) for H. pylori eradication was previously demon...

Label-free detection of pathogens is of major concern to the microbiologist community. Most procedures require several steps and amplification techniques. Carbohydrates are well-established receptors for host-pathogen interactions, which can be amplified using glycodendritic architectures on the basis of multivalent binding interactions. Given that...

Bacterial biofilms account for 80% of all chronic infections, with cells being up to 1000 times more resistant to antibiotics than their planktonic counterparts. The recently discovered ability of Helicobacter pylori to form biofilms once again highlights why this bacterium is one of the most successful human pathogens. The current treatments failu...

The multifunctional properties of antimicrobial peptides (AMPs) make them attractive candidates for the treatment of various diseases. AMPs are considered as alternatives to antibiotics due to the increasing number of multidrug-resistant (MDR) bacteria. However, bare AMPs have limited therapeutic potentials due to a low residence time in the blood...

MSI-78A (Pexiganan A) is one of the few antimicrobial peptides (AMPs) able to kill Helicobacter pylori, a pathogenic bacterium that colonizes the gastric mucosa of half of the world's population. Antibiotics fail in 20-40% of H. pylori-infected patients, reinforcing the need for alternative treatments. Herein, a bioengineered approach was developed...

Bacterial infections are the most eminent public health challenge of the 21st century. The primary step leading to infection is bacterial adhesion to host cells or surfaces, which is mediated by a multitude of molecular interactions. At the interface of life sciences and physics, the massive advances seen over the last years in atomic force microsc...

Human mesenchymal stem/stromal cells (hMSC) are promising therapeutic agents for regenerative medicine. However, therapeutic doses necessary for clinical application require in vitro expansion, ideally under Xeno-Free (XF) conditions to avoid the use of foetal bovine serum (FBS). We previously reported that hMSCs could be expanded using a pharmaceu...

As we approach the end of the antibiotic era, newer therapeutic options, such as antimicrobial peptides (AMPs), are in urgent demand. AMP surface grafting onto biomaterials has been described as a good strategy to overcome problems associated with their in vivo stability. Helicobacter pylori is among the bacteria that pose greatest threat to human...

Medical device-associated infections are a major health threat, representing about half of all hospital-acquired infections. Current strategies to prevent this problem based on device coatings with antimicrobial compounds (antibiotics or antiseptics) have proven to be insufficient, often toxic, and even promoting bacterial resistance. Herein, we re...

Laminin immobilization into diverse biological and synthetic matrices has been explored to replicate the microenvironment of stem cell niches and gain insight into the role of extracellular matrix (ECM) on stem cell behavior. However, the site-specific immobilization of this heterotrimeric glycoprotein and, consequently, control over its orientatio...

The available therapy against Helicobacter pylori is based on a combination of antibiotics and proton pump inhibitors. The high prevalence of antibiotic-resistant strains leads to failure of this complex therapeutic regimen, leaving millions of people worldwide without effective therapeutic options. “Nature-derived” bioactive compounds with antibac...

Cynara cardunculus: L. represents a natural source of terpenic compounds, with the predominant molecule being cynaropicrin. Cynaropicrin is gaining interest since it has been correlated to anti-hyperlipidaemia, antispasmodic and cytotoxicity activity against leukocyte cancer cells. The objective of this work was to screen a collection of C. cardunc...

The (bio)conjugation principles that can be applied to functionalize (nano)materials in the context of biomedical applications are vast. In fact, the (bio)conjugation field has particularly advanced at an astonishing pace in the last decades. Instead of being exhaustive, here we aimed to present the basic toolbox that is currently available to a re...

N-acetyl cysteine (NAC) is an FDA-approved drug clinically applied on a broad range of pathologies. Further research has been conducted with this drug to benefit from its antimicrobial activity potential. However, NAC has a very short half-life and therefore strategies that accomplish high local concentrations would be beneficial. In this study, co...

Macroalgae have been seen as an alternative source of molecules with promising bioactivities to use in the prevention and treatment of current lifestyle diseases. In this vein, the lipophilic fraction of short-term (three weeks) cultivated Bifurcaria bifurcata was characterized in detail by gas chromatography–mass spectrometry (GC-MS). B. bifurcata...

Helicobacter pylori is the etiologic agent of several gastric disorders. The growing rates of unsuccessfulness of available antibiotics-based therapy led to the need for non-antibiotic compounds for H. pylori treatment. The antibacterial activity of Eucalyptus nitens and Eucalyptus globulus outer bark lipophilic extracts were evaluated against a pa...

Abstract Helicobacter pylori is a human gastric pathogen considered as the etiologic agent of several gastric disorders, that may range from chronic gastritis to more severe outcomes, including gastric cancer. The current therapeutic scheme relies on the combination of several pharmacological substances, namely antibiotics and proton pump inhibitor...

Penicillin and other antimicrobials discovery revolutionized medicine but, as a consequence of antibiotic misuse, several bacteria evolved to become resistant to multiple antibiotics classes: " the superbugs ". Following the stagnation on the conventional antibiotic-discovery field, scientific attention turned to alternative foundations for the dev...

The strength of binding between the Helicobacter pylori blood group antigen-binding adhesin (BabA) and its cognate glycan receptor, the Lewis b blood group antigen (Le(b)), was measured by means of atomic force microscopy. High-resolution measurements of rupture forces between single receptor-ligand pairs were performed between the purified BabA an...

Helicobacter pylori colonizes the gastric mucosa of half of the world population and persistent infection is related with the increase risk of gastric cancer. Adhesion of H. pylori to the gastric epithelium that is essential for infection is mediated by bacterial adhesin proteins that recognize specific glycan structures (Gly-R) expressed in the ga...

Helicobacter pylori (H. pylori) is one of the most common infectious agents in the world and it is thought to colonize the gastric mucosa of about half of the world's population causing several gastric diseases. In this work, the effect of surface chemistry on H. pylori nonspecific adhesion, viability, and morphology was evaluated using three H. py...