Protein Multilayer Formation on Colloids through a Stepwise Self-Assembly Technique

Abstract

Multilayer films of the proteins fluorescein isothiocyanate-labeled bovine serum albumin (FITC-BSA) and immunoglobulin G (IgG) were assembled on 640 nm diameter polystyrene (PS) latex particles by their alternate deposition with either positively or negatively charged polyelectrolytes. The proteins and polyelectrolytes were deposited under conditions where they were oppositely charged to one another, thereby facilitating growth of the films through electrostatic interactions. The regular, controlled, stepwise assembly of the protein and polyelectrolyte multilayer films was followed by electrophoretic mobility (EPM), single particle light scattering (SPLS), and transmission electron microscopy (TEM) methods. EPM measurements reveal alternating negative and positive ζ-potentials with deposition of each protein and polyelectrolyte layer, respectively, for the FITC-BSA multilayer films. In contrast, no reversal of the surface charge occurred for the deposition of IgG and poly(sodium 4-styrenesulfonate) (PSS) in the construction of IgG multilayers, although an oscillatory behavior in ζ-potential was observed under the conditions studied. Both SPLS and TEM demonstrate that regular, stepwise protein multilayer growth occurs for both FITC-BSA and IgG. TEM also provides direct visual observation that the PS colloids are uniformly coated with protein. The stepwise, alternate assembly technique employed permits nanometer-level control over the thickness of the protein-polyelectrolyte shell surrounding the colloids. The formation of these novel, biologically functional, core-shell particles is expected to impact the areas of biotechnology and biochemical engineering.

Microcapsules for controlled release fabricated via layer-by-layer self-assembly of polyelectrolytes

“…Nano-and micro-encapsulation via LbL self-assembly has potential applications in biochemistry, pharmaceutics, controlled release, cosmetic, and catalyst [4][5][6]. The first approach directly used proteins, for instance, as the depositing species to prepare bioactive core-shell particles [17][18][19]. The second approach involved direct coverage of drug microcrystals, such as ibuprofen (IBU) [20,21], furosemide [22], vitamin K 3 [23], insulin [23], dexamethasone [24,25], and indomethacin [26][27][28] with polyelectrolyte multilayer films for prolonged release.…”

Layer-by-Layer-Assembled Multilayer Films for Transcutaneous Drug and Vaccine Delivery

“…3,7,18,19,[21][22][23][24] The mild aqueous conditions for encapsulating molecules into multilayer films preserves the bioactivity of fragile biomolecules such as proteins and nucleic acids. 21,22,25 By employing degradable polyelectrolytes as building blocks, the ability to tune the degradation kinetics of multilayer assemblies has been demonstrated and used to control the release kinetics of compounds embedded in these films. 20,26 Applications envisioned for such drug-loaded films include antimicrobial-or anti-inflammatory coatings on implants and drug-releasing coatings for stents.…”

Azobenzene Polymers for Photonic Applications

“…The location of these functional units (which may be small molecules, pendants on the polyelectrolyte chains, or particles) within the multilayer stack can be controlled with subnanometer precision. A wide variety of functionalities have been demonstrated, including organic molecules (He et al, 2000a), synthetic polymers , biopolymers (Burke and Barrett, 2003b), natural proteins (Caruso and Mo¨hwald, 1999), colloids (Lvov et al, 1997), inorganic nanoparticles (Kotov et al, 1995), clay platelets (Kleinfeld and Ferguson, 1994) (used as a nacre biomimic [Tang et al, 2003]), dendrimers (Watanabe and Regen, 1994), electrochemically active species (Knoll, 1996), functionalized C 60 (Mattoussi et al, 2000), and even, counterintuitively, uncharged and nonpolar polymer chains (Rouse and Ferguson, 2002). Many research groups have investigated the possibility of incorporating optically responsive azobenzene chromophores into the versatile PEM structures (examples presented in Fig.…”