PACKAGING THE WATER FOR BIO LAB IN A DROP

The possibility of engineering and shaping materials into 2D or 3D constructs from nanometer to millimeter scale is a very highly attractive field of research in different fields of biomedical sciences from tissue engineering to nanomedicine. During the years various techniques have been promoted for the manipulation of biopolymers, like electrospinning and inkjet printing, while only very recently the 3D polymer printing is opening new scenarios for the production of microscale structures. Unfortunately one of the major drawback related to biopolymer manipulation is the rigidity of the micro structure once realized, limiting their application for biomedical purpose and the high resolution printing over large areas. Moreover, great advantage in processing biomaterials could be represented in producing adaptable flexible substrates. A lot of effort has been spent for designing a priori the material morphological properties. Different technological methods including two-photon, soft interference lithography, replica molding and self-folding polymers have been widely used for shaping the material of interest but, chemical-physical pre-treatments are often required protracting the preparation time before and after the fabrication process. In particular, working on biomaterials, it would be of great interest investigating the behavior of cells in complex 3D tissues. In fact, the in vitro construction of a micro environment mimicking the complex 3D tissue could help to understand the cell-materials interactions for stem cells research, cancer research, bioartificial organs, regenerative medicine, pharmaceutical, drug testing or wound dressing applications. Being water the most common biomaterial existing in nature we propose a water-based bottom-up approach in which we let a biopolymer self-assemble over the water surface and we use water for constructive micro-objects by tailoring polymer solution. We describe for the first time a simple and direct water packaging approach to produce 3D structures of polymer sheet. We show an interesting application keeping the film over water creating a small bio lab-in-a-drop for the analysis of model organisms (Caenorhabditis elegans (C. elegans)). An additional approach proposed is based on the fabrication of the polymer film over hydro-gel materials. In fact, the use of hydro-gels as bottom-up fabrication method allows a controlled assembly, achieving complex 3D tissues. The biopolymer micro engineered materials, realized by water packaging, represent a highly promising tool for optics, photovoltaic, nano-micro electronics devices, nanomedicine and tissue engineering applications.