ASSEMBLY OF MULTICOMPONENT PROTEIN FILMS BY MEANS OF ELECTROSTATIC LAYER-BY-LAYER ADSORPTION

Multilayer films which contain ordered layers of more than one protein species were assembled by means of alternate electrostatic adsorption mostly with positively charged poly(ethylenimine) (PEI) or with negatively charged poly(styrenesulfonate) (PSS). Water-soluble proteins used are cytochrome c (Cyt), myoglobin (Mb), lysozyme (Lys), histone f3, hemoglobin (Hb), glucoamylase (GA), and glucose oxidase (GOD). Charged protein layers formed multilayers with linear polymers acting as glue or filler. The assembly was monitored by a quartz crystal microbalance and UV spectroscopy. Linear film growth was observed up to at least 25 molecular layers. The assembly of Mb and Lys, both positively-charged, was realized in alternation with PSS in the form of {PEI/PSS + (Mb/PSS)(2) + (Mb/PSS/Lys/PSS)(4)}. The assembly of oppositely-charged (at pH 6.5) Lys and GOD consists from Lys and GOD layers separated by a polycation/polyanion bilayer: {PEI/PSS/PEI + (PSS/Lys)(2) + PSS/PEI + (GOD/PEI)(6)}. Hb was assembled as ''positive'' unit at pH 4.5 (in alternation with PSS) and as ''negative'' unit at pH 9.2 (in alternation with PEI). A multilayer consisting of alternating montmorillonite, PEI, and GOD layers was also assembled. These biomolecular architecture open a way to construct artificially orchestrated protein systems that can carry out complex enzymic reactions.