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An in situ template fabrication of inorganic nanoparticles using carboxylated PEG-dendritic block copolymers of the GATG family is described as a function of the dendritic block generation, the metal (Au, CdSe) and metal molar ratio. The biocompatibility of the generated nanoparticles analysed in terms of their aggregation in physiological media, cytotoxicity and uptake by macrophages relates to the PEG density of the surface of the hybrids.

ABSTRACT Dendritic-linear-dendritic (DLD) hybrids are highly functional materials combining the properties of linear and dendritic polymers. Attempts to electrospin DLD polymers composed of hyperbranched dendritic blocks of 2,2-bis(hydroxymethyl) propionic acid on a linear poly(ethylene glycol) core proved unsuccessful. Nevertheless, when these DLD hybrids were blended with an array of different biodegradable polymers as entanglement enhancers, nanofibrous nonwovens were successfully prepared by electrospinning. The pseudogeneration degree of the DLDs, the nature of the co-electrospun polymer and the solvent systems used for the preparation of the electrospinning solutions exerted a significant effect on the diameter and morphology of the electrospun fibers. It is worth-noting that aqueous solutions of the DLD polymers and only 1% (w/v) poly(ethylene oxide) resulted in the production of smoother and thinner nanofibers. Such dendritic nanofibrous scaffolds can be promising materials for biomedical applications due to their biocompatibility, biodegradability, multifunctionality, and advanced structural architecture. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45949. [ABSTRACT FROM AUTHOR]

Herein a simple approach to fabricate hybrid nanomaterials based on dendrimers as polymeric stabilizers for the preparation of silver nanoparticles in aqueous medium were presented. Solutions of these functional nanomaterials were used as finishing agents to produce antimicrobial textiles. The concept was verified on different generations of hydroxyl-terminated dendrimers with increasing size from first to fifth generation. The application was tested on two different fabrics types made of cotton and polyester. The thermal fixation was performed at 120 or 160°C. The antimicrobial properties of the treated fabrics were investigated using the bacteriaEscherichia coliandStaphylococcus aureus. The antimicrobial effect of the treated fabrics was found which significant correlates not only with the amount of the silver content in the finishing agent but also with size of the generated Ag-nanoparticles. Furthermore, the results confirmed that the antimicrobial effect rises with increasing the dendrimers’ generations suggested due to decreasing the size of the formed silver particles. By changing both parameters thermal fixation and dendrimers’ generations, the strength of the antimicrobial effect can be controlled in a wide manner. This could be advantageous for applications demanding a textile with a certain antimicrobial effect. [ABSTRACT FROM AUTHOR]

The presented study concerns the preparation and investigation of silver particles in presence of hydroxylated polyester dendrimers used as stabilizing agent. Altogether a full series of water soluble and aliphatic bis-MPA dendrimers from first to fifth generation was used as to stabilize silver nanoparticles in situ. A special focus is set on the biological properties. The antibacterial properties of the dendrimer stabilized silver particles are tested against Escherichia coli and the toxicity against human cells is tested with the human epithelial cell line A549. Under the chosen testing arrangement, it was observed that the silver particles contain a significant antibacterial effect against E. coli. Silver particles stabilized in situ with dendrimers of higher generation seem to contain a stronger antibacterial property. No toxicity against human cells was observed for the silver particles even in case of the highest investigated silver concentration. Altogether the here prepared and investigated silver particles could offer a great potential for application as antibacterial agent with low human toxicity. [ABSTRACT FROM AUTHOR]

The construction of hierarchical materials through controlled self-assembly of molecular building blocks (e.g., dendrimers) represents a unique opportunity to generate functional nanodevices in a convenient way. Transition-metal compounds are known to be able to interact with cationic dendrimers to generate diverse supramolecular structures, such as nanofibers, with interesting collective properties. In this work, molecular dynamics simulation (MD) demonstrates that acetate ions from dissociated Cd(CH3COO)2 selectively generate cationic PPI-dendrimer functional fibers through hydrophobic modification of the dendrimer's surface. The hydrophobic aggregation of dendrimers is triggered by the asymmetric nature of the acetate anions (AcO-) rather than by the precise transition metal (Cd). The assembling directionality is also controlled by the concentration of AcO- ions in solution. Atomic force (AFM) and transmission electron microscopy (TEM) prove these results. This well-defined directional assembly of cationic dendrimers is absent for different cadmium derivatives (i.e., CdCl2, CdSO4) with symmetric anions. Moreover, since the formation of these nanofibers is controlled exclusively by selected anions, fiber disassembly can be consequently triggered via simple ionic competition by NaCl salt. Ions are here reported as a simple and cost-effective tool to drive and control actively the assembly and the disassembly of such functional nanomaterials based on dendrimers. [ABSTRACT FROM AUTHOR]

Abstract: Dendrimer-stabilized nanoparticles are promising candidates for the application of functional nanoparticles in bio- and physiological environments. Herein, a new class of glycodendrimers, 2nd–5th generation poly(propyleneimine) (PPI) dendrimers with dense maltose shell, is used to guide the formation of colloidal gold nanoparticles in aqueous solution at room temperature. The nanoparticles are synthesized by complexing metal ions to the maltose-modified PPI dendrimers followed by chemical reduction or by auto-reduction in the presence of glycodendrimers. In the auto-reduction process, the dendrimer simultaneously serves as effective reducing- and stabilizing agent. The particle size and -size distribution can be controlled directly as a function of dendrimer''s generation with formation of smaller particles at higher dendrimer generations. The results also suggest that different mechanisms (interfacial uptake and dendritic box) are responsible for the stabilization of the nanoparticles in the presence of the glycodendrimers. [Copyright &y& Elsevier]