A bifunctional nanocarrier based on amphiphilic hyperbranched polyglycerol derivatives

Abstract

We here report on the synthesis of a bifunctional nanocarrier system based on amphiphilic hyperbranched polyglycerol (hPG), which is modified by introducing hydrophobic aromatic groups to the core and retaining hydrophilic groups in the shell. "Selective chemical differentiation" and chemo-enzymatic reaction strategies were used to synthesize this new core-shell type nanocarrier. The system shows an innovative bifunctional carrier capacity with both polymeric and unimolecular micelle-like transport properties. Hydrophobic guest molecules such as pyrene were encapsulated into the hydrophobic core of modified hPG via hydrophobic interactions as well as p-p stacking, analogous to a unimolecular micelle system. A second guest molecule, which has a high affinity to the shell like nile red, was solubilized in the outer shell of the host molecule, thus connecting the nanocarrier molecules to form aggregates. This model is confirmed by UV-Vis, fluorescence, atomic force microscopy, and dynamic light scattering, as well as release studies triggered by pH-changes and enzymes. Encapsulated guest molecules, respectively in the core and in the shell, present different controlled release profiles. The bifunctional nanocarrier system is a promising candidate for simultaneous delivery of different hydrophobic drugs for a combination therapy, e.g., in tumor treatment.

Biodegradable Core–Multishell Nanocarriers: Influence of Inner Shell Structure on the Encapsulation Behavior of Dexamethasone and Tacrolimus

“…The samples were lyophilized, redissolved in DMSO-d 6 and analyzed in 1 H NMR. The α-protons and the methylene group adjacent to the ester group on the PEG side were tracked in the 1 H NMR spectra (the protocol was adapted from a method published earlier by our group) [29]. The chemical shift of the α-protons depends on whether the carboxylic acid was esterified or not.…”

Impact of structural differences in hyperbranched polyglycerol–polyethylene glycol nanoparticles on dermal drug delivery and biocompatibility

“…The particles SK1, SK2 [22], and SK5 [23] have been reported previously. We describe here for the first time the synthesis and characterization of SK3 and SK4.…”

“…Additionally, PEG is shielding these alkylated areas so that the single particles cannot aggregate upon hydrophobic interactions and therefore exist as single particles at least in the unloaded state (Table 1). However, when loading Nile red, the formation of larger aggregates (100-200 nm) was observed which is most likely initiated by hydrophobic interactions between Nile red molecules which tends to be located in the outer shell of the particles [23]. The structure of the particles as well as the degree of functionalization with the hydrophobic side chains and the mPEG shells was determined by NMR spectroscopy.…”

“…2. Encapsulation and release of Nile red for SK5 have been studied in detail by UV-VIS, fluorescence, atomic force microscopy, and dynamic light scattering [23] (Fig. 2).…”

Polyester-Based, Biodegradable Core-Multishell Nanocarriers for the Transport of Hydrophobic Drugs

“…For creating an acidic environment, CMS nanocarriers were solubilized in an acetic acid buffer of pH 5.0, while the enzymatic degradation study was performed using non-specific lipase expressed from Candida Antarctica (CAL B) and immobilized on acrylic resin [31,32]. Both studies were performed for five days and sampled at defined time points.…”