Specific and nondisruptive interaction of guanidium-functionalized gold nanoparticles with neutral phospholipid bilayers

Understanding and controlling the interaction between nanoparticles and biological entities is fundamental to the development of nanomedicine applications. In particular, the possibility to realize nanoparticles capable of directly targeting neutral lipid membranes would be advantageous to numerous applications aiming at delivering nanoparticles and their cargos into cells and biological vesicles. Here, we use experimental and computational methodologies to analyze the interaction between liposomes and gold nanoparticles (AuNPs) featuring cationic headgroups in their protecting monolayer. We find that in contrast to nanoparticles decorated with other positively charged headgroups, guanidinium-coated AuNPs can bind to neutral phosphatidylcholine liposomes, inducing nondisruptive membrane permeabilization. Atomistic molecular simulations reveal that this ability is due to the multivalent H-bonding interaction between the phosphate residues of the liposome’s phospholipids and the guanidinium groups. Our results demonstrate that the peculiar properties of arginine magic, an effect responsible for the membranotropic properties of some naturally occurring peptides, are also displayed by guanidinium-bearing functionalized AuNPs.

Cationic copolymerisation of cholesterol vinyl ether with N-allenylpyrrolidone; a route to pharmacologically promising oligomers

Cationic copolymerization of cholesterol vinyl ether with N-allenylpyrrolidone yielded co-oligomers with molecular mass of 1200-2100. The polymerization of N-allenylpyrrolidone involves both 1,2- and 2,3-positions of the allenyl substituent to give four types of units as a result of prototropic isomerization of the initially formed structures. In the developed method, the composition of co-oligomers can be controlled and, hence, their hydrophilic/hydrophobic balance, solubility, and membranotropic properties can also be controlled to change the potential biological activity of the products.