Raleigh-Bernard Instability IN Evaporating Zein-Alcohol Mixtures and ITS EFFECT ON PROTEIN Self Assembly

Zein, a prolamine protein is a promissing material to develop a control release system of poorly soluble drugs. Zein can encapsulate such compounds and its aggregation can be controlled from nanosacle particles to macro-sized continuous film structures. However the use of zein as building block in control release system requires understanding of factors controlling its self-assembly. In our study zein is dissolved in ethanol-water mixture of various concentrations. By the evaporation of ethanol, zein forms various types of self-assembling structures: from nano-aggregates to continuous zein films. It was found experimentally that Raleigh-Bernard instability is controlling factor that determines type of self assembling structures. We propose simple scaling model which allow to determine critical regimes and processing parameters to obtain desired structures protein assemblies. Additional DLVO-based analysis of zein aggregative stability is in good agreement with experimental data.