Nanostructured Complexes of Polyelectrolytes and Charged Polypeptides

Abstract

Nanoparticles and films of complexes between polyelectrolytes (PELs) and oppositely charged polypeptides emphasizing the influence of PEL molecular stiffness on the generated nanostructures are reported. Homopolypeptides like cationic poly(L‐lysine) (PLL) and anionic poly(L‐glutamic acid) (PLG) were used, whose conformations can be changed from random coil to α‐helix by salt type or pH value. PLL and PLG were complexed with standard commercial polyanions (PA) like poly(vinylsulfate) (PVS) or poly(methacrylic acid) (PMAC) and polycations (PC) like poly(diallyldimethylammoniumchloride) (PDADMAC), respectively. In situ attenuated total reflection infrared (ATR‐IR), circular dichroism (CD), and atomic force microscopy (AFM) were used for surface and bulk characterization. Randomly coiled PLL caused spherical PEC particles and isotropically structured PEM films. Whereas, α‐helical PLL resulted in needle‐like or worm‐like PEC particles and anisotropic PEM films. For PEM films consisting of PDADMAC/PLG PLG terminating PEM‐6 was proteininert, while PDADMAC terminating PEM‐7 was proteinactive. PEM films consisting of PDL/PSS showed higher enantiospecific adsorption of α‐helical myoglobin compared to PLL/PSS. These nanoparticles and films are envisioned as bioinert and bioactive material substrates, unidirectional cell growth, polymer/cell scaffolds, and nanocarriers.