Among the various electrospun polymer systems, poly(vinylidene fluoride) (PVDF) has been widely investigated due to its excellent mechanical properties, high chemical resistance and good thermal stability. In this work, the electrospinning technique is used for the fabrication of functional PVDF fibers in order to identify and evaluate the influence of the experimental conditions on the nanofiber properties in terms of optical transmittance, wettability and surface morphology. According to this, a matrix of 4x4 samples has been successfully developed by controlling two operational input parameters such as the resultant applied voltage (from 10 up to 17.5 KV), and the flow rate (from 800 up to 1400 µL/h) for a fixed polymeric precursor concentration (15 wt.%). The experimental results have shown the presence of beads with different shape and size along the electrospun fibers in all the samples of study. The following parameters such as fiber diameter, surface roughness, UV-Vis spectroscopy and water contact angle (WCA) measurements have been deeply analyzed for the optimization of electrospun fiber composite. Finally, on one hand, this study has shown that an increase in the applied voltage has produced a lower light transmittance with the formation of thinner fibers and a lower surface roughness. On the other hand, an increase in the flow rate has produced an increase in the fiber diameter up to a maximum flow rate of 1200 µL/h, although the surface roughness has continued increased due to the presence of beads, playing a key role in the wettability properties.

Gene delivery is a promising therapeutic approach for a variety of diseases. However, the exact physical mechanisms of transfection agent mediated gene delivery are yet to be fully understood. The endosomal membrane is a major barrier for efficient transfection and endosome escape has become known as a crucial step in the delivery of nucleic acids. Previous research revealed distinct reagent-mediated membrane disruption mechanisms: the formation of small pores allowing protons to pass biological membranes and the permeabilization of large molecules such as LDH through amphiphilic translocation. Here, we measure the membrane permeation of protons in cultured cells after exposition to commercial transfection agents at endosomal pH conditions (pH 5.5) using a proton-sensing transistor (ISFET). In addition, we characterize the effect of transfection agents on cytosolic LDH leakage from cultured cells. Comparing the results from both assays at endosomal pH indicate that both types of transfection reagents have pore-forming activity at endosomal pH, while there is no such activity at pH 7.4. The pores formed by polymer-based reagents result in LDH leakage, whereas lipid-based reagents do not. This suggests a mechanistical difference in terms of the size of the pores formed. The effect of this difference on the endosomal escape profile is also investigated with a CLSM-based assay. These data indicate that the ISFET may be used to more accurately assess the endosome escape capabilities of different gene carriers.

Triple negative breast cancer had a phenotype characterized by the absence of progesterone and estrogen receptors and lack of HER2 overexpression. In order to find new strategies for treatment, single-walled carbon nanotubes (SWCNT) in combination with chemotherapeutics were studied and tested as new therapeutic tools. The objective of this study was to evaluate the efficiency of SWCNT in the transport of cisplatin (CDDP) for improving its cytotoxic effects on MDA-MB-231 cells.

The nanoconjugates SWCNT-COOH-CDDP were obtained by functionalization of SWCNT with carboxyl groups (SWCNT-COOH) and conjugation with CDDP. MDA-MB-231 cells were exposed to different doses of SWCNT-COOH, SWCNT-COOH-CDDP (0.01 – 2 µg/mL) and CDDP (0.00632 – 1.26 µg/mL) for 24 and 48 h. Cellular viability was monitored through MTT test. The level of reactive oxygen species (ROS) and reduced glutathione (GSH) were evaluated using fluorescence and spectrophotometric methods, respectively. The expressions of Nrf2, caspase-3, caspase-8 and Bid proteins were assessed by immunoblotting in the presence of 0.5 and 1 µg/mL nanoconjugates. Also, the effects of SWCNT-COOH-CDDP on cell migration were monitored using Wound healing assay.

The cellular viability decreased, respectively ROS level increased in a time and dose-dependent manner in the presence of nanoconjugates relative to control. Moreover, the level of GSH raised after 24 and 48 h of exposure to 0.5 µg/mL SWCNT-COOH-CDDP, while a decrease until 78.31% was recorded after 48 h in the presence of 1 µg/mL nanoconjugates. The expression of Nrf2 decreased until 33% after 24 h of treatment with 1 µg/mL SWCNT-COOH-CDDP and increased until 80% compared to control (100%) after 48 h. Up-regulation of caspase-3 and caspase-8 and down-regulation of Bid post-exposure to 1 µg/mL SWCNT-COOH-CDDP was noticed. The inhibition of the cell migration was observed after 24 and 48 h of exposure with 1 µg/mL SWCNT-COOH-CDDP. In conclusion, these nanoconjugates induced apoptosis in MDA-MB-231 cells, probably by both intrinsic and extrinsic pathways, by triggering the oxidative stress mechanisms, and inhibited their migration potential.

Alterations in neurogenesis result in the inevitable loss of brain nervous tissue and cause neurodegenerative diseases, such as Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease (HD). In this regard, hydrogels based on natural biopolymers have attractive properties, such as excellent biocompatibility, a low immune response and a significant similarity to the extracellular matrix (ECM) of tissues, thus supporting cell proliferation and migration. Human ECM is composed by relatively small amounts of fibrous, proteins and polysaccharides. For example, scaffolds composed of gelatin and hyaluronic acid are highly abundant components in human ECM.

The methacrylation of hyaluronic acid (HAMA) and gelatin (GelMA) through carboxyl and hydroxyl groups under UV light radiation at 365 nm produce polymeric scaffolds with elastic moduli similar to tissues, and therefore, potential candidates to adhere, host and facilitate cell proliferation and differentiation, which are dependent on their mechanical properties. In this work, the mechanical, thermal and morphological properties of HAMA and GelMA hydrogel mixtures were studied and characterized via linear rheological measurements, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM).

During the last few years, Metal Organic Frameworks (MOFs) are being considered as ideal candidates to find more efficient systems for the production and storage of energy[1]. MOFs are characterized by their large specific surface due to ultra high porosity, tunable pore size distribution and structural tailorability. These characteristics will determine the properties obtained, and derived from them, their potential applications such as clean energy storage[2], CO₂ capture and other separation processes[3,4], biomedical imaging[5], optical luminescence and catalysis[6].

Recently, zeolitic structures based on imidazolates groups as organic ligand (ZIFs) have appeared as an important subfamily of MOFs which present a high surface area, adjustable pore size, thermal stability above 500 ºC and high chemical stability in aqueous and organic media. The synthetic route developed for the fabrication of metallic crystalline networks composed of Co²⁺ and 2-methylimidazole is simple, carried out in aqueous medium and at room temperature. The synthetic process used in this work for obtaining MOFs is based on a surfactant method[7] in which different proportions of the constituents were used.

The physicochemical characterization and the colloidal stability were carried out by dynamic light scattering (DLS), scanning transmission electron microscopy (STEM) and thermogravimetric analysis (TGA). Furthermore, we investigate the influence of the surfactant Cetyl Trimethyl Ammonium Bromide (CTAB) as well as the use of different solvents on the colloidal stability and themorphology, structure and chemistry of the synthesized systems.

Cardiovascular diseases (CVD) is a general term to enclose diseases that affect the circulatory system and/or the heart. Their underlying pathology is atherosclerosis, an inflammatory disease characterized by the accumulation of lipids, inflammatory cells and fibrous tissue in the arteries internal wall, provoking in some extent their obstruction. Atherosclerosis is still addressed as a simple disease instead of being faced as the complex interplay of different types of cells and cascade signaling pathways, so that the use of any single imaging or therapeutic agent alone is unlikely to provide a satisfactory outcome. Hence, other treatment strategies need to be implemented, in particular, new nanomaterials able to target the plaque, to efficiently treat it and that can be easily released by the body without provoking adverse effects. Following this premises, we have designed a biocompatible drug delivery vehicle that efficiently load and protect the drug Atorvastatin (ATO reduces the LDL levels) while a folate receptor in the external shell will target inflamed areas. To avoid the common toxic effects of Folic acid (FA) or ATO in the body at certain concentrations, the vehicle will provide covalent attachment for the FA on the surface and cage structure for ATO protection. To complement the treatment, genetic material will be included in separate compartment to actively influence regulation of immune responses and inflammatory disorders.

Self-assembly of nanometric structures from molecular building blocks is an effective way to make new functional materials for biological and technological applications. In this work we synthesized new dimeric bolaamphiphilic dehydrodipeptides, containing phenylalanine connected to a dehydroamino acid residue at the C-terminus. The N- terminus of the dipeptide was connected to both ends of a bifunctional central aromatic moiety, namely 1,4-benzenedicarboxylic acid and 1,3-benzenedicarboxylic acid. The potential use of these new compounds as hydrogelators was evaluated. The results showed that these compounds synthesised behave as efficient molecular hydrogelators, forming hydrogels with minimum gelation concentrations of 0.3-0.8 wt%.

The self-assembly of these hydrogelators was investigated by STEM microscopy technique, revealing different shapes depending on the N-aromatic moiety. STEM microscopy revealed that the hydrogels are composed by fibers, ribbons and even sheres. Circular dichroism spectroscopy was also performed in order to evaluate the aggregation of the peptides into characteristic secondary structures.

Polyurethanes (PUs) are defined as a big group of synthetic polymers that contain repeated urethane linkage in the backbone. The obtained polymer can differ in shape and properties, depending on the components and the synthesis process. That is why PUs are widely used in a big range of applications. Due to their good biocompatibility, it is possible to manufacture polyurethane-based biomaterials as well. Another big advantage of polyurethanes is the ease of modification, using many types of fillers.

One of the most commonly used fillers in biomedical applications is hydroxyapatite (HAp), a calcium phosphate mineral. HAp-like compounds build around 65% of a bone, therefore HAp is a good alternative for a synthetic bone modifier. PU-based materials with an addition of HAp can exhibit not only enhanced osteogenesis but also improved mechanical properties such as tensile strength and Young modulus.

In this work, polyurethane-based bone scaffolds manufactured in the two-step bulk polyaddition process were presented. The influence of various HAp content was investigated. The chemical structure of the samples was checked using spectroscopy (FTIR). Mechanical properties were evaluated by a compression test. Bioactivity of the material was investigated based on SEM images before and after incubation in SBF solution.

Magnetic Resonance Imaging (MRI) is at the forefront of clinical imaging. Paramagnetic relaxers (Gd³⁺ and Mn²⁺ chelates, iron oxide nanoparticles) shorten the relaxation times (T_1,2) i.e. enhance the relaxation rates (R_1,2= 1/T_1,2) of the water protons in their vicinity yielding significant contrast enhancements-contrast agents. Supramolecular (self-assembled) hydrogels based on low molecular weight peptides are the new paradigm biomaterials: porous soft biocompatible materials made of highly hydrated fibrous 3D nanostructures, reminiscent of the extracellular matrix. Our research group developed self-assembled hydrogels based on dehydrodipeptides N-capped with naproxen (Npx, a NSAID drug). Dehydropeptide-based hydrogels exhibit resistance to proteolysis, are biocompatible and suitable nanocarriers for delivery of incorporated drugs. Recently, we demonstrated that incorporation of SPION endows dehydropeptide-based hydrogels with magnetic properties (magnetogels): hyperthermia and MRI reporting properties. In this communication we report novel supramolecular hydrogels prepared by co-assembly of dehydropeptides and Gd³⁺ chelates. The hydrogels are characterised regarding co-assembly (fluorescence, CD spectroscopy) and micro- nano-structure (STEM) and rehologial properties. The co-assembled hydrogels are characterized also as Contrast Agents for MRI by ¹H relaxometry (60 MHz, 37ºC) and MRI (120 MHz, 37 ºC).

Chronic wounds are a health problem of enormous magnitude that affects millions of patients around the world. The most promising treatments for chronic wounds healing are the therapies related to the development of biomimetic technologies that successfully improve cell migration, growth and proliferation. The implementation of scaffolds or hydrogels, based on natural and biosynthetic extracellular matrix (ECM) or individual components of ECM, have shown to provide an adequate environment to enhance cellular migration, angiogenesis and regulation of wound healing processes. Additionally, electrostimulation therapies have gained attention in recent years due to their capability for simulating electric currents to direct cell migration, promote cell proliferation and increase oxygenated blood perfusion towards damaged tissues. In the present work, we propose innovative regenerative 3D scaffolds based on small intestinal submucosa (SIS) combined with graphene oxide (GO)/reduced graphene oxide (rGO) to improve their electrical conductivity such that they can be potentially applied in the healing of chronic wounds. To achieve this, decellularized SIS was obtained and mixed with GO flakes to make 3D scaffolds that were chemically crosslinked and reduced in-situ. GO and rGO were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, atomic force microscopy (AFM) and the four-point probe conductivity method. These techniques confirmed the effective synthesis of GO, the reduction to rGO and the improvement of electrical conductivity. Crosslinked SIS, SIS-GO and SIS-rGO scaffolds were characterized by FTIR, TGA, SEM, Raman spectroscopy and liquid displacement method. In addition, the biocompatibility of scaffolds was carried out via hemolysis activity, platelet aggregation, and cytotoxicity in Vero cells. Experiments revealed high hemocompatibility, low cytotoxicity and no significant impact on platelet aggregation. Finally, microscopic structure characteristics and cell attachment abilities demonstrated the potential of the developed technology for multiple applications in tissue engineering and regenerative medicine.