Understanding novel EGFP-Ubx protein-based film formation

Protein-based materials are currently the subject of intense research interest since they have an extended range of potential applications, such as im-proved bio-membrane biocompatibility for implanted medical devices and the creation of platform materials for novel biosensors. Monomers from Ultrabithorax (Ubx) transcription factor are known to spontaneously self-assemble at an air-water interface to form a monolayer, which has then been used as a basis for forming biopolymeric ˝bers. Here we used the Lang-muir trough technique, Brewster angle microscopy (BAM), ellipsometry and neutron re˛ectometry (NR) to investigate the in˛uences of di˙erent exper-imental conditions on EGFP-Ubx monolayer formation and the impact on biopolymeric ˝ber structure. We varied protein concentration, bu˙er prop-erties and waiting times prior to forming biopolymeric ˝bers. Interestingly, we found 3 phases of material formation which brought us to a new protocol for forming ˝bers that reduced protein concentration by 5-fold and wait-ing times by 100-fold. Moreover, an in-house developed MATLAB code was used to analyze SEM images and obtain quantitative structural information about the biopolymeric ˝bers that were correlated directly to the surface ˝lm characteristics measured in the LB trough. These new insights into ˝ber formation and structure enhance the usefulness of the Ubx-based biopolymer for biomedical applications.