Behavior of PPI-G2 Dendrimer in a Microemulsion

Abstract

Dendrimer nanostructures are of eminent interest in biomedical applications because of their uniform and well-defined molecular size and shape, and their ability to cross cell membranes and reduce the risk of premature clearance from the human body. Dendrimers perform as gene and drug carriers and have also shown significant therapeutic properties for treating cancer and neurodegenerative diseases. A complex drug delivery system, based on a dendrimer solubilized in the aqueous core of a water-in-oil (W/O) microemulsion (ME) along with the drug may combine the advantages of both dendrimers and MEs to provide better control of drug release. We propose a new microemulsion composed of drug-permitted surfactants and dendrimer that can be used as a potential controlled drug delivery nanosystem. The influence of second generation poly(propyleneimine) (PPI-G2) dendrimer; solubilized in (W/O) ME with a capacity of up to 25 wt% PPI-G2 at various pHs; and their interactions with the surfactant phosphatidylcholine (PC), cosurfactant (butanol), and water was studied. SAXS and EPR measurements indicated that increasing PPI-G2 concentration reduces droplet curvature and increases droplet size thus increasing macro-(SAXS) and micro-(EPR) order degree. Furthermore, SD-NMR and ATR-FTIR show stronger interactions between PPI-G2 and water molecules at the expense of PC and butanol headgroups hydration, which increases microviscosity (EPR). PPI-G2's effect is somewhat opposite to the increasing water phase effect, thus reducing the amount of free water (DSC) and slowing the mobility of all ME components (SD-NMR).

PAMAM-Based Dendrimers with Different Alkyl Chains Self-Assemble on Silica Surfaces: Controllable Layer Structure and Molecular Aggregation

“…However, the slope becomes smaller with lengthening of the hydrophobic tails at the same frequency, suggesting that the adlayers are more rigid and flatten with longer hydrophobic tails, probably because the water content of adlayer is lower in the presence of dendrimers with longer hydrophobic tails. The self-assembly and rearrangement of amphiphilic molecules occur mainly through hydrophobic interaction due to the entropy-driven tendency, − in which more water molecules can be repulsed outside for longer hydrophobic tails. It seems that the repulsion of water makes the molecular conformation become more flat for dendrimers with longer hydrophobic tails (Figure ).…”

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

“…Among the available tools for studying nanoparticle–cell interactions, electron paramagnetic resonance (EPR) spectroscopy has excelled in providing on-site structural and dynamical information. The spin-probe/spin-label-based EPR technique has already been demonstrated to be a powerful tool in characterizing the interactions of dendrimers with model membranes and cells [10,13,14,15,16,17,18,19,20,21,22,23,24], and has even been used in living systems [25]. Importantly, EPR spectroscopy shares many of the features of magnetic resonance imaging (MRI), including the underlying principles, and exhibits superior detection sensitivity.…”