A mechanistic view of lipid membrane disrupting effect of PAMAM dendrimers

Abstract

The effect of 5 th generation polyamidoamine (PAMAM G5) dendrimers on multilamellar dipalmitoylphosphocholine (DPPC) vesicles was investigated. PAMAM was added in two different concentration to the lipids (10 -3 and 10 -2 dendrimer/lipid molar ratios). The thermal behavior of the evolved systems was characterized by DSC; while the structure and the morphology were investigated with small-and wide-angel X-ray scattering (SWAXS), freeze-fracture electron microscopy (FFTEM) and phosphorus-31 nuclear magnetic resonance ( 31 P-NMR) spectroscopy, respectively. IR spectroscopy was used to study the molecular interactions between PAMAM and DPPC. The obtained results show that the dendrimers added in 10 -3 molar ratio to the lipids generate minor perturbations in the multilamellar structure and thermal character of liposomes, while added in 10 -2 molar ratio dendrimers cause major disturbance in the vesicular system. The terminal amino groups of the dendrimers are in strong interaction with the phosphate headgroups and through this binding dendrimers disrupt the regular multilamellar structure of DPPC. Besides highly swollen, fragmented bilayers, small vesicles are formed.

PAMAM dendrimer - cell membrane interactions

“…5b, revealed that there was no change in d-spacing (or bilayer thickness) of the MLVs upon dendrimer addition. However, broadening of the peaks with increasing dendrimer concentration indicated a loss in the number of bilayers, and this effect was also observed by Berenyi et al with G5 dendrimers interacting with DPPC MLVs [110]. The bilayers in onion-like MLVs experience van der Waals, hydration and thermal undulation forces.…”

“…Berenyi et al [110] found that G5 PAMAM altered the pre-transition DSC peak of DPPC MLVs, shown in Fig. 5d, which indicated an interaction between dendrimers and the lipid polar headgroups and an increase in membrane fluidity, also confirmed by infrared spectroscopy.…”

Improved DNA condensation, stability, and transfection with alkyl sulfonyl-functionalized PAMAM G2

“…DPPC is a zwitterionic lipid that bears a positive charge from the choline group and a negative charge from the phosphate. At the air-water interface, the polar heads of the phospholipids are oriented into the bulk so that the dendriplexes can interact electrostatically with the phosphate group (Berenyi et al 2014). The increment of surface pressure shown in Fig.…”

Preparation of self-assembled core–shell nano structure of conjugated generation 4.5 poly (amidoamine) dendrimer and monoclonal Anti-IL-6 antibody as bioimaging probe

“…On the other hand, WAXS patterns of G4.5 and G4.5/IL-6 in the small angle region indicated supramolecular ordering [33]. Two-dimensional WAXS patterns were azimuthally integrated to one-dimensional I(q) profiles along the radial coordinates (see Fig.…”