Search

Two of the main types of nanotubular architectures are the single-walled carbon nanotubes (SWCNTs) and the self-assembling cyclic peptide nanotubes (SCPNs). We here report the preparation of the dual composite resulting from the ordered combination of both tubular motifs. In the resulting architecture, the SWCNTs can act as templates for the assembly of SCPNs that engage the carbon nanotubes noncovalently via pyrene "paddles", each member of the resulting hybrid stabilizing the other in aqueous solution. The particular hybrids obtained in the present study formed highly ordered oriented arrays and display complementary properties such as electrical conductivity. Furthermore, a self-sorting of the cyclic peptides toward semiconducting rather than metallic SWCNTs is also observed in the aqueous dispersions. It is envisaged that a broad range of exploitable properties may be achieved and/or controlled by varying the cyclic peptide components of similar SWCNT/SCPN hybrids.

A novel, water-soluble trans-platinum complex was synthesized by inclusion complexation with beta-cyclodextrin. The complexation was confirmed by (1)H NMR, FT-IR, TGA, and XRD as well as by SEM and EDX. As the precursor complex is not water-soluble, it is difficult to employ it for biological applications. Here, we report that the encapsulation with cyclodextrin allowed to solubilize the complex to a solubility value of 1.6 mg/mL. Moreover, the cytotoxicity in vitro of the novel inclusion complex indicated a much higher activity after encapsulation.

Radical copolymerization of styrene (St) and maleic anhydride (Man) was performed in supercritical carbon dioxide (SC CO2) at 50−80 °C with 2,2‘-azoisobutyronitrile as the initiator. A novel, ultrahigh molecular mass St−Man alternative copolymers (Mw > 106) has been synthesized. The NMR spectra demonstrated that the copolymers obtained possess strictly alternating structure. Aqueous solutions of the alternative copolymers exhibit lower critical solution temperatures (LCST). These LCST's are highly sensitive to changes in the molecular weight and pH. St/MAn copolymerization in SC CO2 as the solvent yielded higher molecular weight products and more cis configuration linkage of cyclic MAn units in the copolymer chains than those made in common organic solvents. These facts demonstrate that SC CO2 as the solvent plays an important role in the copolymerization of styrene with maleic anhydride, originating from the special intermolecular interactions between SC CO2 and St−Man alternative copolymer.

DNA-wrapped nanotubes of both multiwalled and single-walled carbon nanotubes were obtained by a solid-state mechanochemical reaction. Scanning electron microscopic images show that the nanotubes were cut into shorter lengths and were fully covered with DNA, which was further confirmed by fluorescence microscopy. This resulted in a high aqueous solubility of the products with a stability of6 months. The results show that nanotubes were cut also with uniform distribution where90% of the multiwalled products were 500 nm to 3 microm and 80% of the single-walled products were 250 nm to 1 microm in length, respectively. UV-vis spectra and gel electrophorosis show that the DNA in the product is intact. This facile technique for obtaining supramolecularly masked, water-soluble carbon nanotubes by a solid-state reaction has a great potential for both biological and nonbiological applications of nanotubes.

The applications of separation techniques using ultrafiltration in connection with functional soluble polymers for the removal of environmentally relevant and toxic substances from waters are reviewed. The types of interactions of the soluble polymers with low molecular mass compounds, the criteria for selecting the appropriate polymeric agents, and the binding conditions are discussed. Several factors influencing the separation of the target substances such as membrane type, solution composition, synergism, polymer adsorption, deformation of macromolecules, and hydrodynamics are evaluated and highlighted. Chemical, electrochemical, and thermal regeneration aspects are also covered. Finally, an overview on varius preparative and analytical application examples is presented.