Pegylated Gold Nanoparticles Conjugated with siRNA: Complexes Formation and Cytotoxicity.

Drug delivery systems such as dendrimers, liposomes, polymers or gold/silver nanoparticles could be used to advance modern medicine. One significant pharmacological problem is crossing biological barriers by commonly used drugs, e.g., in the treatment of neurodegenerative diseases, which have a problem of the blood-brain barrier (BBB) restricting drug delivery. Numerous studies have been conducted to find appropriate drug carriers that are safe, biocompatible and efficient. In this work, we evaluate pegylated gold nanoparticles AuNP14a and AuNP14b after their conjugation with therapeutic siRNA directed against APOE4. This genetic risk factor remains the strongest predictor for late-onset Alzheimer's disease. The study aimed to assess the biophysical properties of AuNPs/siAPOE complexes and to check their biological safety on healthy cells using human brain endothelial cells (HBEC-5i). Techniques such as fluorescence polarization, circular dichroism, dynamic light scattering, ζ-potential measurements and gel retardation assay showed that AuNPs form stable complexes with siRNA. Subsequently, cytotoxicity assays proved the biological safety of formed conjugates. Obtained results enabled us to find effective concentrations of AuNPs when complexes are formed and non-toxic for healthy cells. One of the studied nanoparticles, AuNP14b complexed with siRNA, displayed lower cytotoxicity (MTT assay, cells viability -74.8 ± 3.1%) than free nanoparticles (44.7 ± 3.6%). This may be promising for further investigations in nucleic acid delivery and could have practical use in treating neurodegenerative diseases.

The Antibacterial Effect of PEGylated Carbosilane Dendrimers on P. aeruginosa Alone and in Combination with Phage-Derived Endolysin.

The search for new microbicide compounds is of an urgent need, especially against difficult-to-eradicate biofilm-forming bacteria. One attractive option is the application of cationic multivalent dendrimers as antibacterials and also as carriers of active molecules. These compounds require an adequate hydrophilic/hydrophobic structural balance to maximize the effect. Herein, we evaluated the antimicrobial activity of cationic carbosilane (CBS) dendrimers unmodified or modified with polyethylene glycol (PEG) units, against planktonic and biofilm-forming P. aeruginosa culture. Our study revealed that the presence of PEG destabilized the hydrophilic/hydrophobic balance but reduced the antibacterial activity measured by microbiological cultivation methods, laser interferometry and fluorescence microscopy. On the other hand, the activity can be improved by the combination of the CBS dendrimers with endolysin, a bacteriophage-encoded peptidoglycan hydrolase. This enzyme applied in the absence of the cationic CBS dendrimers is ineffective against Gram-negative bacteria because of the protective outer membrane shield. However, the endolysin-CBS dendrimer mixture enables the penetration through the membrane and then deterioration of the peptidoglycan layer, providing a synergic antimicrobial effect.

Reconstruction of a Compound Oromandibular Defect by Means of Chimeric Scapular-Parascapular Free Flap Assisted by Virtual Surgical Planning.

BACKGROUND: Reconstruction of an oromandibular defect presents a considerable surgical challenge. But since the advent of microvascularized free flap reconstructive surgery, outcomes have improved significantly so that today almost any defect may be reconstructed. Recently, virtual surgical planning has reduced surgical time, the morbidity associated with surgery, and surgical precision. OBJECTIVE: This article reports a complex patient with a composite oromandibular defect. METHODS: The patient had undergone multiple surgeries with bad results. She presented an orostoma of 5 cm in diameter, osteoradionecrosis and fracture of the left mandibular body, and relapse in the ipsilateral posterior maxilla. Reconstruction was performed by means of a scapular/parascapular chimeric free flap. A customized reconstruction plate was designed virtually based on the mirror image of the contralateral mandibular body. Surgery and the postoperative phase passed without incident. The patient recovered vocal, swallowing, and respiratory function without any problems. At the end of a 1-year follow-up, no complications or tumor relapse had occurred. CONCLUSIONS: Composite defects are a surgical challenge in which free flap reconstruction is an evolution that has facilitated treatment and led to improved outcomes. Virtual treatment planning produces more exact results and greater control of surgical techniques.

Polyanionic carbosilane dendrimers prevent hepatitis C virus infection in cell culture.

Hepatitis C virus (HCV) infection is a major biomedical problem worldwide. Although new direct antiviral agents (DAAs) have been developed for the treatment of chronic HCV infection, the potential emergence of resistant virus variants and the difficulties to implement their administration worldwide make the development of novel antiviral agents an urgent need. Moreover, no effective vaccine is available against HCV and transmission of the virus still occurs particularly when prophylactic measures are not taken. We used a cell-based system to screen a battery of polyanionic carbosilane dendrimers (PCDs) to identify compounds with antiviral activity against HCV and show that they inhibit effective virus adsorption of major HCV genotypes. Interestingly, one of the PCDs irreversibly destabilized infectious virions. This compound displays additive effect in combination with a clinically relevant DAA, sofosbuvir. Our results support further characterization of these molecules as nanotools for the control of hepatitis C virus spread.

Polyanionic carbosilane dendrimer-conjugated antiviral drugs as efficient microbicides: Recent trends and developments in HIV treatment/therapy.

Polyanionic carbosilane dendrimers (PCDs) are potential candidates for the development of new microbicides for the prevention of HIV transmission. Tenofovir (TFV), which has dual antiviral activity (anti-HIV/HSV-2), and maraviroc (MRV) are the most studied antiretrovirals as microbicides. Here, we introduce developments in the design of innovative dendrimer-based microbicides. We also review and discuss the combination of various PCDs with TFV and/or MRV for their anti-HIV-1 activity and synergistic combinatory potential. Well-defined combinations blocking HIV-1 infection in early steps of HIV-1 replication provide greater efficacy than monotherapy, as reflected by the decrease in concentration and increase in HIV-1 inhibition. These combinations are characterized by lower doses, which minimize toxic side-effects and the emergence of multi-drug resistant mutants. The above facts suggest that the combination of first- and second-generation PCDs with TFV and/or MRV represents a promising candidate microbicide for preventing HIV-1 sexual transmission and simultaneously suppressing HSV-2. FROM THE CLINICAL EDITOR: HIV infection remains a significant and unresolved problem for humankind, despite the development of combination antiretroviral therapy. It has been found that polyanionic carbosilane dendrimers have efficacy in preventing HIV transmission. In this comprehensive review article, the authors discuss the current status and latest development of the use of dendrimers in combination with other antiretroviral drugs as microbicides, which should stimulate others into further research in the fight against HIV.

Dendronized Ag/Au Nanomats: Antimicrobial Scaffold for Wound Healing Bandages.

Electrospun polymer nanofibers, due to high surface area-to-volume ratio, high porosity, good mechanical strength, and ease of functionalization, appear as promising multifunctional materials for biomedical applications. Thanks to their unidirectional structure, imitating the extracellular matrix (ECM), they can be used as scaffolds for cell adhesion and proliferation. In addition, the incorporation of active groups inside nanofiber can give properties for bactericides. The proposed nanomats incorporate nanoparticles templated within the electrospun nanofibers that prevent infections and stimulate tissue regeneration. The generated hybrid electrospun nanofibers are composed of a copolymer of L-lactide-block-ε-caprolactone (PL-b-CL), 70:30, blended with homopolymer polyvinylpyrrolidone (PVP) and gold (Au) nanoparticles. A low cytotoxicity and slightly increased immunoreactivity, stimulated by the nanomat, are observed. Moreover, the decoration of the hybrid nanomat with dendronized silver nanoparticles (Dend-Ag) improves their antibacterial activity against antibiotic-resistant Pseudomonas aeruginosa. The use of Dend-Ag for decorating offers several functional effects; namely, it enhances the antibacterial properties of the produced nanomats and induces a significant increase within macrophages' cytotoxicity. The unidirectional nanostructures of the generated hybrid nanomats demonstrate unique collective physio-chemical and biological properties suitable for a wide range of biomedical applications. Here, the antibacterial properties facilitate an optimal environment, contributing to accelerated wound healing.

Hyperbranched polymers versus dendrimers containing a carbosilane framework and terminal ammonium groups as antimicrobial agents.

A new family of amine- and ammonium-terminated hyperbranched polycarbosilanes (PCS) and dendrimers has been synthesized. The functionalization of a polycarbosilane matrix was carried out with peripheral allyl groups by two strategies in the case of PCS: 1) hydrosilylation of allyl amines with PCS containing terminal Si-H bonds, or 2) hydrosilylation of PCS-allyl with an aminosilane. Dendrimers with terminal amine groups were synthesized by hydrosilylation of allydimethylamine. Quaternized systems with MeI are soluble and stable in water or other protic solvent. The antibacterial properties of the ammonium-terminated hyperbranched polycarbosilanes and dendrimers have been evaluated showing that they act as potent biocides against Gram-positive and Gram-negative bacterial strains.

PEGylation of Dendronized Gold Nanoparticles Affects Their Interaction with Thrombin and siRNA.

The use of nonviral carriers based on nanomaterials is a promising strategy for modern gene therapy aimed at protecting the genetic material against degradation and enabling its efficient cellular uptake. To improve the effectiveness of nanocarriers in vivo, they are often modified with poly(ethylene glycol) (PEG) to reduce their toxicity, limit nonspecific binding by proteins in the bloodstream, and extend blood half-life. Thus, the selection of an appropriate degree of surface PEGylation is crucial to preserve the interaction of nanoparticles with the genetic material and to ensure its efficient transport to the site of action. Our research focuses on the use of innovative gold nanoparticles (AuNPs) coated with cationic carbosilane dendrons as carriers of siRNA. In this study, using dynamic light scattering and zeta potential measurements, circular dichroism, and gel electrophoresis, we investigated dendronized AuNPs modified to varying degrees with PEG in terms of their interactions with siRNA and thrombin to select the most promising PEGylated carrier for further research.

Effect of PEGylation on the biological properties of cationic carbosilane dendronized gold nanoparticles.

Heterofunctionalized gold nanoparticles (AuNPs) were obtained in a one pot reaction of gold precursor with cationic carbosilane dendrons (first to third generations, 1-3G) and (polyethylene)glycol (PEG) ligands in the presence of a reducing agent. The final dendron/PEG proportion on AuNPs depends on the initial dendron/PEG ratio (3/1, 1/1, 1/3) and dendron generation. AuNPs were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), ultraviolet spectroscopy (UV-VIS), thermogravimetric analysis (TGA), nuclear magnetic resonance (1H NMR) and zeta potential (ZP). Several assays have been carried out to determine the relevance of PEG/dendron ratio and dendron generation in the biomedical properties of PEGylated AuNPs and the results have been compared with those obtained for non-PEGylated AuNPs. Finally, analyses of PEG recognition by anti-PEG antibodies were carried out. In general, haemolysis, platelet aggregation and toxicity were reduced after PEGylation of AuNPs, the effect being dependent on dendron generation and dendron/PEG ratio. Dendron generation determines the exposure of PEG ligand and the interaction of this ligand with AuNPs environment. On the other hand, increasing PEG proportion diminishes toxicity but also favors interaction with antibodies.

PEGylated AgNP covered with cationic carbosilane dendrons to enhance antibacterial and inhibition of biofilm properties.

This work focuses on preparation of silver nanoparticles (AgNP) covered with cationic carbosilane dendrons and poly(ethylene glycol) (PEG). It is well known that AgNP and cationic carbosilane dendritic systems present antibacterial properties. On the other hand, PEG ligand provides antifouling properties and improved biocompatibility. Hence, combination of both ligands, carbosilane dendrons and PEG, on the AgNP surface can be a way to improve antibacterial capacity of AgNP. The new family of heterofunctionalized AgNP has been directly synthesized using silver precursor and cationic carbosilane dendrons and PEG ligands containing a thiol moiety. AgNP were characterized by TEM, TGA, UV, 1H NMR, DLS, Z potential, XRD. The antibacterial capacity of these systems was evaluated against E. coli and S. aureus. The results confirmed the influence of both silver core and cationic carbosilane dendrons on the activity of these systems. The behaviour obtained for PEGylated systems were slightly lower than for non-PEGylated AgNP. However, hemolysis assays demonstrated that this decrease was compensated for by the greater biocompatibility. To more completely characterize the improvements of PEGylation on dendronized AgNP, one non-PEGylated and one PEGylated AgNP were tested for resistance in a planktonic state. Both AgNPs barely affected the minimum inhibitory concentration (MIC) whereas reference antibiotics generated significant resistance. In addition, relevant improvement in biofilm inhibition was achieved by dendronized AgNP after PEGylation.

Exploring the Interactions of Ruthenium (II) Carbosilane Metallodendrimers and Precursors with Model Cell Membranes through a Dual Spin-Label Spin-Probe Technique Using EPR.

Dendrimers exhibit unique interactions with cell membranes, arising from their nanometric size and high surface area. To a great extent, these interactions define their biological activity and can be reported in situ by spin-labelling techniques. Schiff-base carbosilane ruthenium (II) metallodendrimers are promising antitumor agents with a mechanism of action yet to explore. In order to study their in situ interactions with model cell membranes occurring at a molecular level, namely cetyltrimethylammonium bromide micelles (CTAB) and lecithin liposomes (LEC), electron paramagnetic resonance (EPR) was selected. Both a spin probe, 4-(N,N-dimethyl-N-dodecyl)ammonium-2,2,6,6-tetramethylpiperidine-1-oxyl bromide (CAT12), able to enter the model membranes, and a spin label, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) covalently attached at newly synthesized heterofunctional dendrimers, were used to provide complementary information on the dendrimer-membrane interactions. The computer-aided EPR analysis demonstrated a good agreement between the results obtained for the spin probe and spin label experiments. Both points of view suggested the partial insertion of the dendrimer surface groups into the surfactant aggregates, mainly CTAB micelles, and the occurrence of both polar and hydrophobic interactions, while dendrimer-LEC interactions involved more polar interactions between surface groups. We found out that subtle changes in the dendrimer structure greatly modified their interacting abilities and, subsequently, their anticancer activity.

New anionic carbosilane dendrons functionalized with a DO3A ligand at the focal point for the prevention of HIV-1 infection.

Novel third-generation polyanionic carbosilane dendrons with sulfonate or carboxylate end-groups and functionalized with a DO3A ligand at the focal point, and their corresponding copper complexes, have been prepared as antiviral compounds to prevent HIV-1 infection. The topology enables the compound to have an excellent chelating agent, DO3A, while keeping anionic peripheral groups for a therapeutic action. In this study, the cytotoxicity and anti-HIV-1 abilities of carboxylate- (5) or sulfonate-terminated (6) dendrons containing DO3A and their copper complexes (7 or 8) were evaluated. All compounds showed low cytotoxicity and demonstrated potent and broad-spectrum anti-HIV-1 activity in vitro. We also assessed the mode of antiviral action on the inhibition of HIV-1 through a panel of different in vitro antiviral assays. Our results show that copper-free dendron 6 protects the epithelial monolayer from short-term cell disruption. Copper-free dendrons 5 and 6 exert anti-HIV-1 activity at an early stage of the HIV-1 lifecycle by binding to the envelope glycoproteins of HIV-1 and by interacting with the CD4 cell receptor and blocking the binding of gp120 to CD4, and consequently HIV-1 entry. These findings show that copper-free dendrons 5 and 6 have a high potency against HIV-1 infection, confirming their non-specific ability and suggesting that these compounds deserve further study as potential candidate microbicides to prevent HIV-1 transmission.

Prevention of vaginal and rectal herpes simplex virus type 2 transmission in mice: mechanism of antiviral action.

Topical microbicides to stop sexually transmitted diseases, such as herpes simplex virus type 2 (HSV-2), are urgently needed. The emerging field of nanotechnology offers novel suitable tools for addressing this challenge. Our objective was to study, in vitro and in vivo, antiherpetic effect and antiviral mechanisms of several polyanionic carbosilane dendrimers with anti-HIV-1 activity to establish new potential microbicide candidates against sexually transmitted diseases. Plaque reduction assay on Vero cells proved that G2-S16, G1-S4, and G3-S16 are the dendrimers with the highest inhibitory response against HSV-2 infection. We also demonstrated that our dendrimers inhibit viral infection at the first steps of HSV-2 lifecycle: binding/entry-mediated events. G1-S4 and G3-S16 bind directly on the HSV-2, inactivating it, whereas G2-S16 adheres to host cell-surface proteins. Molecular modeling showed that G1-S4 binds better at binding sites on gB surface than G2-S16. Significantly better binding properties of G1-S4 than G2-S16 were found in an important position for affecting transition of gB trimer from G1-S4 prefusion to final postfusion state and in several positions where G1-S4 could interfere with gB/gH-gL interaction. We demonstrated that these polyanionic carbosilan dendrimers have a synergistic activity with acyclovir and tenofovir against HSV-2, in vitro. Topical vaginal or rectal administration of G1-S4 or G2-S16 prevents HSV-2 transmission in BALB/c mice in values close to 100%. This research represents the first demonstration that transmission of HSV-2 can be blocked by vaginal/rectal application of G1-S4 or G2-S16, providing a step forward to prevent HSV-2 transmission in humans.

Antiviral mechanism of polyanionic carbosilane dendrimers against HIV-1.

Nanotechnology-derived platforms, such as dendrimers, are very attractive in several biological applications. In the case of human immunodeficiency virus (HIV) infection, polyanionic carbosilane dendrimers have shown great potential as antiviral agents in the development of novel microbicides to prevent the sexual transmission of HIV-1. In this work, we studied the mechanism of two sulfated and naphthylsulfonated functionalized carbosilane dendrimers, G3-S16 and G2-NF16. They are able to inhibit viral infection at fusion and thus at the entry step. Both compounds impede the binding of viral particles to target cell surface and membrane fusion through the blockage of gp120-CD4 interaction. In addition, and for the first time, we demonstrate that dendrimers can inhibit cell-to-cell HIV transmission and difficult infectious synapse formation. Thus, carbosilane dendrimers' mode of action is a multifactorial process targeting several proteins from viral envelope and from host cells that could block HIV infection at different stages during the first step of infection.

[Drugs having latex and therapeutic alternatives in hospital formulary]. / Medicamentos con látex y alternativas en guía farmacoterapéutica.

OBJETIVE: To analyze the latex content of drugs in hospital formulary and establish possible therapeutic alternatives. METHODS: All drugs susceptible of having latex were selected and written information was obtained from manufacturers. A therapeutic alternative was found for each of them, if possible. RESULTS: Written information from manufacturer was obtained for 605 (97.9%) and from label information for 8 of 632 selected drugs. For 43.9% of not safe drugs (total 57) on patients with latex allergy, a therapeutic alternative was found in hospital formulary. CONCLUSIONS: Knowing drugs having latex improve the prescription security, while the therapeutic alternatives chart eases the validation. The published data updates the scarce and variable information for patients and healthcare professionals.

Objetivo: Analizar el contenido en látex de los medicamentos en la guía farmacoterapéutica y establecer alternativas en un hospital de tercer nivel. Método: Se seleccionaron los medicamentos susceptibles de contener látex en su material de acondicionamiento, se solicitó al laboratorio fabricante información y se buscaron posibles alternativas incluidas en guía farmacoterapéutica. Resultados: De las 618 especialidades seleccionadas se obtuvo información escrita del laboratorio para 605 (97.9%) y en ficha técnica para 8. De las 57 (9,2%) especialidades con riesgo en pacientes con alergia al látex se encontró una alternativa en guía para el 43,9%. Conclusiones: Conocer las especialidades con látex aumenta la seguridad en la prescripción, mientras que la disponibilidad de una tabla de equivalencias terapéuticas facilita la validación. Los datos publicados vienen a actualizar la información del contenido en látex de los medicamentos para pacientes y personal sanitario, generalmente escasa y variable.

Novel non-viral gene delivery systems composed of carbosilane dendron functionalized nanoparticles prepared from nano-emulsions as non-viral carriers for antisense oligonucleotides.

The development of novel and efficient delivery systems is often the limiting step in fields such as antisense therapies. In this context, poly(d,l-lactide-co-glycolide) acid (PLGA) nanoparticles have been obtained by a versatile and simple technology based on nano-emulsion templating and low-energy emulsification methods, performed in mild conditions, providing good size control. O/W polymeric nano-emulsions were prepared by the phase inversion composition method at 25°C using the aqueous solution/polysorbate80/[4 wt% PLGA in ethyl acetate] system. Nano-emulsions formed at oil-to-surfactant (O/S) ratios between 10/90-90/10 and aqueous contents above 70 wt%. Nano-emulsion with 90 wt% of aqueous solution and O/S ratio of 70/30 was chosen for further studies, since they showed the appropriate characteristics to be used as nanoparticle template: hydrodynamic radii lower than 50 nm and enough kinetic stability. Nanoparticles, prepared from nano-emulsions by solvent evaporation, showed spherical shape, sizes about 40 nm, negative surface charges and high stability. The as-prepared nanoparticles were functionalized with carbosilane cationic dendrons through a carbodiimide-mediated reaction achieving positively charged surfaces. Antisense oligonucleotides were electrostatically attached to nanoparticles surface to perform gene-silencing studies. These complexes were non-haemolytic and non-cytotoxic at the concentrations required. The ability of the complexes to impart cellular uptake was also promising. Therefore, these novel nanoparticulate complexes might be considered as potential non-viral carriers in antisense therapy.

HIV-1 antiviral behavior of anionic PPI metallo-dendrimers with EDA core.

The development of novel strategies to prevent HIV-1 infection is of outstanding relevance. Metal complexes of Cu(2+), Ni(2+), Co(2+) and Zn(2+) derived from sulfonated and carboxylated poly(propylene imine) dendrimers with ethylenediamine core were evaluated as tunable antiviral agents against HIV-1. After demonstrating their biocompatibility, specific trends in the antiviral properties were found, related to both the dendritic scaffold (peripheral group, generation) and the bound metal ions (sort, amount). In HEC-1A and VK-2 cell lines, as model of the first barrier against HIV-1 infection, a high preventive inhibitory action was found, which also avoided virus internalization inside cells and inhibited both CCR5 and CXCR4 HIV-1 strains. In peripheral blood mononuclear cells (PBMC), as model of the second barrier, a dual preventive and therapeutic behavior was observed. A rational design of such metallodendrimers opens new avenues for the production of versatile and efficient treatments against HIV-1 infection.

Amphiphilic cationic carbosilane-PEG dendrimers: synthesis and applications in gene therapy.

Here we synthesized carbosilane, generation 1 to 3, and PEG-based dendrons functionalized at the periphery with NHBoc groups and at the focal point with azide and alkyne moieties, respectively. The coupling of these two types of dendrons via click chemistry led to the formation of new hybrid dendrimers with two distinct moieties, the hydrophobic carbosilane and the hydrophilic PEG-based dendron. The protected dendrimers were transformed into cationic ammonium dendrimers. These unique amphiphilic dendrimers were studied as vectors for gene therapy against HIV in peripheral blood mononuclear cells (PBMC) and their performance was compared with that of a PEG-free carbosilane dendrimer. The presence of the PEG moiety afforded lower toxicities and evidenced a weaker interaction between dendrimers and siRNA when compared to the homodendrimer analogous. Both features, lower toxicity and lower dendriplex strength, are key properties for use of these vectors as carriers of nucleic material.

Basic concepts in the taxonomy of health-related behaviors, habits and lifestyle.

BACKGROUND: Health-related Habits (HrH) are a major priority in healthcare. However there is little agreement on whether exercise, diet, smoking or dental hygiene are better described as lifestyles, habits or behaviors, and on what is their hierarchical relationship. This research is aimed at representing the basic concepts which are assumed to constitute the conceptual framework enabling us to interpret and organize the field of HrH. METHODS: A group of 29 experts with different backgrounds agreed on the definition and hierarchy of HrH following an iterative process which involved framing analysis and nominal group techniques. RESULTS: Formal definitions of health-related behavior, habit, life-style and life-style profile were produced. In addition a series of basic descriptors were identified: health reserve, capital, risk and load. Six main categories of HrH were chosen based on relevance to longevity: diet/exercise, vitality/stress, sleep, cognition, substance use and other risk. Attributes of HrH are clinical meaningfulness, quantifiability, temporal stability, associated morbidity, and unitarity (non-redundancy). Two qualifiers (polarity and stages of change) have also been described. CONCLUSIONS: The concepts represented here lay the groundwork for the development of clinical and policy tools related to HrH and lifestyle. An adaptation of this system to define targets of health interventions and to develop the classification of person factors in ICF may be needed in the future.

Anionic sulfonated and carboxylated PPI dendrimers with the EDA core: synthesis and characterization of selective metal complexing agents.

Herein we describe the synthesis and characterization of new sulfonated and carboxylated poly(propyleneimino) (PPI) dendrimers with the ethylenediamino (EDA) core, at generations 1, 2 and 3. By means of UV-Vis and EPR spectroscopy, using Cu(2+) as a probe, we concluded that these dendrimers show a specific pattern in the coordination of metal ions. In agreement with the UV-Vis studies, EPR spectra of carboxylated compounds are constituted by 3 different signals which appear and then disappear with increasing copper concentration, corresponding to the saturation of different copper complexation sites. At the lowest copper concentration up to a 1:1 molar ratio between Cu(II) and the dendrimer, the spectrum is characteristic of a CuN2O2 coordination at the core of the dendrimer. The spectrum appearing at higher Cu(II) concentrations indicates a peripheral location of the ions coordinating one nitrogen and 3 oxygen atoms in a square planar geometry in restricted mobility conditions. For the highest concentrations tested, copper ions are confined at the external dendrimer surface with CuO4 coordination. For sulfonate systems, the EPR results are in line with a weaker interaction of Cu(II) with the nitrogen sites and a stronger interaction with the oxygen (SO3(-)) groups with respect to the interactions measured by EPR for carboxylate systems.