Quantal Self-Assembly of Polymer Layers in Polypeptide Multilayer Nanofilms

Abstract

Simple molecular models predict key aspects of the "microscopic" assembly behavior of various peptide systems in the fabrication of multilayer films. Such films show substantial differences in density for different peptide systems. The data suggest that exponential film growth is possible in the absence of polymer diffusion and that "macroscopic" assembly behavior is more a function of peptide-peptide interactions than peptide sequence alone.

Controlled loading and release of a model drug from polypeptide multilayer nanofilms

“…Optical thickness of the films followed the trend: pH 7.4 b pH 5.5 b pH 4.0 ( Figure 2, A), consistent with previous findings [24]. Film thickness was least when the linear charge density of peptides was greatest [6,24]. The electrostatic force repels peptides of the same sign of charge, limiting the amount of polymer deposited per layer [25].…”

“…The main driving force for the adsorption of species from solution is electrostatic attraction and the entropy gain from release of counterions; the availability of charged groups on the film surface is crucial for controlled deposition of material. Hydrogen bonds and hydrophobic interactions too can influence LBL multilayer nanofilm assembly [4][5][6]. Polymers in adjacent layers interpenetrate [7,8].…”

“…Various structural properties of polypeptides under the control of the molecular engineer could be useful for the encapsulation and controlled release of small molecules in biological or medical applications of multilayer nanofilms [10,14], including linear charge density [15,16], immunogenicity [17], susceptibility to enzymatic digestion [10], and antimicrobial activity [18]. Other means of controlling the release of encapsulated materials include control over film density [16], surface morphology [16], stability [18,19], and susceptibility to environmental perturbation [13], all of which are functions of peptide design and film architecture [10].…”

“…Other means of controlling the release of encapsulated materials include control over film density [16], surface morphology [16], stability [18,19], and susceptibility to environmental perturbation [13], all of which are functions of peptide design and film architecture [10]. Introduction of micropores or nanopores into a multilayer film (e.g., by immersion in a strong acid or base or subjection to high temperature [20]) could also be used to influence the rate of release [21].…”

Polypeptide multilayer nanofilm artificial red blood cells

“…Indeed, we have demonstrated that control over peptide sequence represents a means of control over useful film properties. [42][43][44] Assembly behavior of given polypeptides in a multilayer film will depend on propensity to form secondary structure, pH, ionic strength, presence of cosolvents, and so on. The broad range of process control variables enables the engineering of physical, chemical, and biological properties of multilayer filmbased structures.…”