Polypeptide multilayer films: role of molecular structure and charge.
The role of molecular structure, charge, and hydrophobicity in polyelectrolyte layer-by-layer assembly (LbL) of thin films has been studied using the model polypeptides poly-L-glutamatic acid (PLGA) and poly-L-lysine (PLL), quartz crystal microbalance (QCM), and circular dichroism spectroscopy (CD). The adsorption behavior of PLGA and PLL has been compared with the structure of these molecules in aqueous solution under the same conditions. The data show that the deposition of polypeptide per adsorption step scales with average secondary structure content, whether alpha helix or beta sheet. This is contrary to the expectation based on the view that hydrogen bonds are crucial to polypeptide film assembly, because secondary structure formation in a polypeptide reduces its intermolecular hydrogen-bonding potential. The data also show that polypeptide adsorption scales with ionic strength and chain length. Taken together, the results increase knowledge of polypeptide-based LbL thin film fabrication and will help to provide a firmer foundation for the use of natural or designed polypeptides in LbL.
Haynie
Donald T
DT
Biomedical Engineering, Institute for Micromanufacturing, Louisiana Tech University, P.O. Box 10137, Ruston, Louisiana 71272, USA.
Balkundi
Shantanu
S
Palath
Naveen
N
Chakravarthula
Kiran
K
Dave
Komal
K
D001704:Biopolymers / Q000737:chemistry; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D055672:Static Electricity
D001704:Biopolymers; D010455:Peptides