Iva Pashkuleva - Academia.edu (original) (raw)

Papers by Iva Pashkuleva

Macromolecular bioscience, May 20, 2016

There is an urgent need for antitumor bioactive agents with minimal or no side effects over norma... more There is an urgent need for antitumor bioactive agents with minimal or no side effects over normal adjacent cells. Fucoidan is a marine-origin polymer with known antitumor activity. However, there are still some concerns about its application due to the inconsistent experimental results, specifically its toxicity over normal cells and the mechanism behind its action. Herein, three fucoidan extracts (FEs) have been tested over normal and breast cancer cell lines. From cytotoxicity results, only one of the extracts shows selective antitumor behavior (at 0.2 mg mL(-1) ), despite similarities in sulfation degree and carbohydrates composition. Although the three FEs present different molecular weights, depolymerization of selected samples discarded Mw as the key factor in the antitumor activity. Significant differences in sulfates position and branching are observed, presenting FE 2 the higher branching degree. Based on all these experimental data, it is believed that these last two prop...

Advanced Drug Delivery Reviews, 2015

The extracellular matrix (ECM) of tissues is an assembly of insoluble macromolecules that specifi... more The extracellular matrix (ECM) of tissues is an assembly of insoluble macromolecules that specifically interact with soluble bioactive molecules and regulate their distribution and availability to cells. Recapitulating this ability has been an important target in controlled growth factor delivery strategies for tissue regeneration and requires the design of multifunctional carriers. This review describes the integration of supramolecular interactions on the design of delivery strategies that encompass self-assembling and engineered affinity components to construct advanced biomimetic carriers for growth factor delivery. Several glycan- and peptide-based self-assemblies reported in the literature are highlighted and commented upon. These examples demonstrate how molecular design and chemistry are successfully employed to create versatile multifunctional molecules which self-assemble/disassemble in a precisely predicted manner, thus controlling compartmentalization, transport and delivery. Finally, we discuss whether recent advances in the design and preparation of supramolecular delivery systems have been sufficient to drive real translation towards a clinical impact.

Biodegradable Systems in Tissue Engineering and Regenerative Medicine, 2004

Organic Preparations and Procedures International, 1999

Journal of tissue engineering and regenerative medicine, Jan 14, 2016

Textile-based technologies are powerful routes for the production of three-dimensional porous arc... more Textile-based technologies are powerful routes for the production of three-dimensional porous architectures for tissue engineering applications because of their feasibility and possibility for scaling-up. Herein, the use of knitting technology to produce polybutylene succinate fibre-based porous architectures is described. Furthermore, different treatments have been applied to functionalize the surface of the scaffolds developed: sodium hydroxide etching, ultraviolet radiation exposure in an ozone atmosphere and grafting (acrylic acid, vinyl phosphonic acid and vinyl sulphonic acid) after oxygen plasma activation as a way to tailor cell adhesion. A possible effect of the applied treatments on the bulk properties of the textile scaffolds has been considered and thus tensile tests in dry and hydrated states were also carried out. The microscopy results indicated that the surface morphology and roughness were affected by the applied treatments. The X-ray photoelectron spectroscopy and ...

Org Prep Procedure Int, 1999

11Th International Biorelated Polymer Symposium 243rd National Spring Meeting of the American Chemical Society, Mar 1, 2012

Journal of the American Chemical Society, Dec 25, 2014

Acta Biomaterialia, 2016

This work reports on the development of infection-preventive coatings on silicone urinary cathete... more This work reports on the development of infection-preventive coatings on silicone urinary catheters that contain in their structure and release on demand antibacterial polycationic nanospheres. Polycationic aminocellulose conjugate was first sonochemically processed into nanospheres to improve its antibacterial potential compared to the bulk conjugate in solution (ACSol). Afterward the processed aminocellulose nanospheres (ACNSs) were combined with the hyaluronic acid (HA) polyanion to build a layer-by-layer construct on silicone surfaces. Although the coating deposition was more effective when HA was coupled with ACSol than with ACNSs, the ACNSs-based coatings were thicker and displayed smoother surfaces due to the embedment of intact nanospheres. The antibacterial effect of ACNSs multilayers was 40% higher compared to ACSol coatings. This fact was further translated into more effective prevention of Pseudomonas aeruginosa biofilm formation. The coatings were stable in the absence of bacteria, whereas their disassembling occurred gradually during incubation with P. aeruginosa, and thus eradicate the biofilm upon release of antibacterial agents. Only 5 bilayers of HA/ACNSs were sufficient to prevent the biofilm formation, in contrast to the 10 bilayers of ACSol required to achieve the same effect. The antibiofilm efficiency of (HA/ACNSs)10 multilayer construct built on a Foley catheter was additionally validated under dynamic conditions using a model of the catheterized bladder in which the biofilm was grown during seven days. Antibacterial layer-by-layer coatings were fabricated on silicone that efficiently prevents Pseudomonas aeruginosa biofilm formation during time beyond the useful lifetime of the currently employed urinary catheters in medical practice. The coatings are composed of intact, highly antibacterial polycationic nanospheres processed from aminated cellulose and bacteria-degrading glycosaminoglycan hyaluronic acid. The importance of incorporating nanoscale structures within bacteria-responsive surface coatings to impart durable antibacterial and self-defensive properties to the medical indwelling devices is highlighted.

Analytica Chimica Acta, 2015

We describe the use of gel permeation chromatography (GPC) setup with four size exclusion columns... more We describe the use of gel permeation chromatography (GPC) setup with four size exclusion columns for analysis of enzymatically digested glycosaminoglycans (GAGs). This setup provides information about the molecular weight (Mw) and concentration of all species (low and high Mw) present in the digests in a single measurement. The data about the fraction with high Mw (often omitted in the analysis of GAG digests) provide direct evidence about the mechanisms of action of the enzymes. We proved the feasibility of this methodology by applying it to chondroitin sulfate (CS) substrates with different molecular weight and sulfation pattern and using different enzymes (hyaluronidase and chondroitinase). NMR analysis of the obtained digests fractionated by ultrafiltration confirmed the results obtained by GPC setup and reveal further details about the degradation mechanisms: (i) both enzymes preferentially

Glycosaminoglycans (GAGs) comprise the closest cellular environment: they are building elements o... more Glycosaminoglycans (GAGs) comprise the closest cellular environment: they are building elements of the ECM and can be also found on cells surface. Their biological activity depends on several parameters among which the negative charge is of prime importance[1]. This charge is generally associated with the presence of sulfate groups (-OSO 3 H). Sulfation is a dynamic modification: it can occur at various positions within the glycan and different sulfation patterns have been identified for the same organs and cells during their development. However, the mechanisms of coding and transferring information by these functionalities are not yet complete understood, mainly because of (i)the complex physiological microenvironment in which GAGs interactions occur and (ii)the inability to access homogeneous GAGs [2]. In this work, we propose model surfaces bearing GAGs with different sulfation degree as platform to investigate the pathways by which mesenchymal stem cells (MSCs) sense and respond to this peculiar functionality: the -OSO 3 H. We have selected two natural GAGs for this study: hyaluronic acid (HA) because it is the only non-sulfated glycan and heparin (HEP) as it is the GAG with the highest degree of sulfation. To obtain a larger range of sulfation degrees, we have also prepared a synthetic analogue of HA with a sulfation degree of 1.4 (sHA). All these GAGs were covalently bonded to aminothiols deposited on gold surfaces. MSCs, both from bone marrow and adipose tissue, adhered well to all surfaces. Formation of focal adhesions was observed after only 1h of culture for bone marrow derived MSCs regardless the used substrate. The presence of -OSO 3 H groups induced different morphology and cytoskeleton organisation: formation of longer filopodia and well pronounced actin fibers were visible for the MSCs from both sources. Moreover, cells were more spread after 24h in contact with -OSO 3 H containing surfaces. Cells behaved similarly on both sulfated surfaces (sHA and HEP) and differences in cell morphology were less obvious: higher sulfation degree induced less lamellipodia formation while filopodia number and length increased. In summary, the present study provides evidence that sulfation degree of GAGs triggers distinct cytoskeleton organisation in mesenchymal stem cells that may be related with the differentiation of those cells. However, further studies at the molecular level about the exact mechanism of these processes need to be carried out.

Generating Micro- and Nanopatterns on Polymeric Materials, 2011

Page 1. 13 Polymer Patterns and Scaffolds for Biomedical Applications and Tissue Engineering Natá... more Page 1. 13 Polymer Patterns and Scaffolds for Biomedical Applications and Tissue Engineering Natália M. Alves, Iva Pashkuleva, Rui L. Reis, and João F. Mano 13.1 Introduction Polymers have gained a remarkable place in ...

Journal of the American Chemical Society, 2015

Journal of Materials Chemistry B, 2014

Oxime click reaction is used for the synthesis of diblock copolymers of polyethylene glycol (PEG)... more Oxime click reaction is used for the synthesis of diblock copolymers of polyethylene glycol (PEG) and glycosaminoglycans (GAGs) with different molecular weights (M w ) and sulfation degrees. The ability of these copolymers to carry positively charged proteins is evidenced by their assembly with poly-L-lysine as a model: interpolyelectrolyte complexes with tunable size at the nanometric scale (radius of 25-90 nm) and narrow distribution are described. We demonstrate that there is a critical M w of GAGs for the formation of stable complexes and that the sulfation degree determines the size of the nano-assemblies.

Langmuir, 2013

FGF-2 is often used as a supplement to stem cells culture medium aiming at preserving their self-... more FGF-2 is often used as a supplement to stem cells culture medium aiming at preserving their self-renewal capacity and plasticity through the passages. However, little is known on the influence of the underlying substrate in these interactions. In this study, we have used mixed self-assembled monolayers with different ratios of -SO3H and -OH tail groups to investigate the influence of substrate properties (e.g., charge) on the FGF-2 adsorption and activity. QCM-D data demonstrated that, in the presence of -OH groups, the quantity of the adsorbed FGF-2 is proportional to the percentage of surface -SO3H groups. The bioactivity of the adsorbed FGF-2 follows the same tendency as demonstrated by its interactions with anti-FGF-2. Surprisingly, the adlayer of FGF-2 formed on the surface containing only SO3H-tailed SAMs was similar to the surface with 25% of -SO3H groups, demonstrating that FGF-2 adsorption is not solely driven by electrostatic interactions. We related these results with changes in the morphology of adipose-derived stem cells (ASCs) cultured on the same surfaces.

Journal of Materials Chemistry, 2010

During the past few years, the field of tissue engineering (TE) has been shifting from replacemen... more During the past few years, the field of tissue engineering (TE) has been shifting from replacement to regenerative strategies. Following this tendency, the requirements for biomaterials to be used in TE have been also changing. While a few decades ago bioinert materials that do not provoke undesired body responses were in the focus of material sciences, nowadays third generation biomaterials mimicking the nanoscale mechanisms of the interactions between cells and their in vivo environment are the target of material design. Although these mechanisms involve different bioactive molecules, until now mainly strategies involving small peptide epitopes that copycat specific sequences of complex proteins have been exploited. The breakthroughs that such approaches brought to biomaterials and TE fields are undeniable. Nevertheless, the important role that carbohydrates play in tissue structuring and function is still poorly explored and exploited in this context and we believe that this is one of the missing pieces in the TE puzzle. Carbohydrates are an integral part of our life. We are literally covered by them: from bacteria to mammalian cells, the molecular landscape of the cell surface is coated with sugars forming the so-called glycocalyx. This strategic placement of the sugars makes them crucial for the development, growth, function and/or survival of an organism. It is believed that the structural diversity of carbohydrates is the key for understanding and controlling those processes because of the huge number of ligand structures, which sugars can display in molecular recognition systems. However, their main advantages: the intricacy and the large natural diversity have turned against the scientists and have hampered their study. As a result, the field of glycomics is much less developed compared to its counterparts genomics and proteomics within TE. Recent advances in carbohydrate synthesis, sensing technologies and processing methodologies are inducing rapid changes in this field and will be discussed in this paper. The use of carbohydrates as an interrogation and modulation tool for better understanding of the complexity and dynamics of the natural three-dimensional environment of the cells will be also focussed.

Journal of Biomedical Materials Research Part A, 2012

The aim of this work was the preparation and characterization of scaffolds with mechanical and fu... more The aim of this work was the preparation and characterization of scaffolds with mechanical and functional properties able to regenerate bone. Porous scaffolds made of chitosan/gelatin (POL) blends containing different amounts of a bioactive glass (CEL2), as inorganic material stimulating biomineralization, were fabricated by freeze-drying. Foams with different compositions (CEL2/POL 0/100; 40/60; 70/30 wt %/wt) were prepared. Samples were crosslinked using genipin (GP) to improve mechanical strength and thermal stability. The scaffolds were characterized in terms of their stability in water, chemical structure, morphology, bioactivity, and mechanical behavior. Moreover, MG63 osteoblast-like cells and periostealderived stem cells were used to assess their biocompatibility. CEL2/POL samples showed interconnected pores having an average diameter ranging from 179 6 5 lm for CEL2/POL 0/ 100 to 136 6 5 lm for CEL2/POL 70/30. GP-crosslinking and the increase of CEL2 amount stabilized the composites to water solution (shown by swelling tests). In addition, the SBF soaking experiment showed a good bioactivity of the scaffold with 30 and 70 wt % CEL2. The compressive modulus increased by increasing CEL2 amount up to 2.1 6 0.1 MPa for CEL2/POL 70/30. Dynamical mechanical analysis has evidenced that composite scaffolds at low frequencies showed an increase of storage and loss modulus with increasing frequency; furthermore, a drop of E 0 and E 00 at 1 Hz was observed, and for higher frequencies both moduli increased again. Cells displayed a good ability to interact with the different tested scaffolds which did not modify cell metabolic activity at the analyzed points. MTT test proved only a slight difference between the two cytotypes analyzed.