RESUMO
Hyperbranched polymers are obtained through one-step polymerization reactions and exhibit properties that are very similar to those of perfect dendrimer analogues. Therefore, hyperbranched polymers are a suitable alternative for perfect dendrimers as building blocks for dendritic nanocarrier systems. With regard to using soluble hyperbranched polymers as carrier systems, their flexible chains are a major benefit as they can adopt and compartment guest molecules. Upon encapsulation, the properties of the host decides the fate of the guest, e.g., solubility, but the host can also shield a guest from the environment and protect it, e.g., from degradation and deactivation. With regard to the advantages of using hyperbranched polymers as nanocarrier systems and their scalable synthesis, we will discuss different types of hyperbranched polymers and their application as nanocarrier systems for drugs, dyes, and other guest molecules.
RESUMO
The solubilization behavior of nile red dye in aqueous surfactant and micellar solutions was studied by optical spectroscopic techniques, dynamic light scattering, and atomic force microscopy. Nile red exhibits considerable absorption in the submicellar concentration region. When dispersed in aqueous surfactant and/or micellar solution, nile red molecules tend to form nonemissive dimers and/or H-type aggregates through π-π stacking interactions. This phenomenon may limit the use of nile red in solubilization studies. In the presence of ionic SDS and CTAB micelles, the solubilization of nile red appears to take place primarily at the charged micellar surface within the interfacial region. Similarly, spectra in micellar solution of nonionic Triton X-100 revealed that nile red dye penetrates the hydrophilic, interfacial poly(oxyethylene) region of the micelles but cannot reach the hydrophobic, innermost core. Our results therefore suggest that nile red dye must be chosen carefully when probing (micellar) hydrophobic environments and (micro)domains.
