Bacterial Inclusion Bodies (IBs) are protein deposits usually observed in recombinant bacteria during protein production processes. These aggregates have been historically regarded as waste by-products and therefore discarded. However, in the last two decades this perception has changed. Numerous studies have provided evidence that these particles are in fact supramolecular structures formed by stereospecific cross-molecular protein-protein interactions, morphologically and mechanically stable, easy to purify and highly tunable in terms of biological activity, size and physicochemical properties,. In the present work it has been explored to exploit appealing IB properties for biomedical applications. In this regard, we have focused on the suitability of IBs as particulate protein nanomaterial to produce engineered nanotopographies able to modulate mammalian cell responses. Nanomodification of scaffolds to stimulate a specific cell response is a promising field for tissue engineering and regenerative medicine. In this regard, we have provided evidence that bacterial IBs can be effectively deposited onto cell culture surfaces generating altered nanotopographies. These IB-based topographies, when used as cell culture substrate, exhibited higher capability for cell adhesion in four distinct cell lines. Moreover, IBs were shown to be able of actively stimulating cell proliferation through mechanotransductive events, being these two activities crucial for cell colonization of implant materials. On the other hand, it has been also proved how IB-based topographies are able to direct mesenchymal stem cells (MSCs) to osteogenesis. Noteworthy, cell adhesion, cell proliferation and cell differentiation can be controlled by the proper choice of Escherichia coli producing strain genetic background, rendering physicochemically and morphologically distinct IBs. Finally, IBs have been shown capable of releasing significant amounts of their forming protein, prompting their use as a delivery platform of therapeutic protein drugs, from nanostructured surfaces to cell cultures. This last application would be particularly appealing for long term treatments, since IBs provide a sustained release of their active component. Moreover, this delivery capacity adds an extra level of complexity and control to the previous mentioned IB applications, through the combination of the mechanical effect of the IB-based topographies with the biological activity of the IB-forming protein.
Biomedical Applications of Bacterial Inclusion Bodies
Seras Franzoso, J. (Author). 13 Dec 2012
Student thesis: Doctoral thesis
Student thesis: Doctoral thesis