2 research outputs found
Auxiliary Biomembranes as a Directional Delivery System To Control Biological Events in Cell-Laden Tissue-Engineering Scaffolds
Delivery of growth factors is an
indispensable part of tissue engineering.
Here, we describe a detachable membrane-based release system composed
of extracellular matrix components that can be attached to hydrogels
to achieve directional release of bioactive molecules. This way, the
release of cytokines/growth factors can be started at a desired point
of tissue maturation or directly in vivo. As a model, we develop thin
films of an interpenetrating network of double-cross-linked gelatin
and hyaluronic acid derivatives. The use of the auxiliary release
system with vascular endothelial growth factor results in extensive
sprouting by encapsulated vascular endothelial cells. The presence
of the release system with interleukin-4 results in clustering of
encapsulated macrophages with a significant decrease in M1 macrophages
(proinflammatory). This system can be used in conjunction with three-dimensional
structures as an auxiliary system to control artificial tissue maturation
and growth
Biomimetic Cryptic Site Surfaces for Reversible Chemo- and Cyto-Mechanoresponsive Substrates
Chemo-mechanotransduction, the way by which mechanical forces are transformed into chemical signals, plays a fundamental role in many biological processes. The first step of mechanotransduction often relies on exposure, under stretching, of cryptic sites buried in adhesion proteins. Likewise, here we report the first example of synthetic surfaces allowing for specific and fully reversible adhesion of proteins or cells promoted by mechanical action. Silicone sheets are first plasma treated and then functionalized by grafting sequentially under stretching poly(ethylene glycol) (PEG) chains and biotin or arginine-glycine-aspartic acid (RGD) peptides. At unstretched position, these ligands are not accessible for their receptors. Under a mechanical deformation, the surface becomes specifically interactive to streptavidin, biotin antibodies, or adherent for cells, the interactions both for proteins and cells being fully reversible by stretching/unstretching, revealing a reversible exposure process of the ligands. By varying the degree of stretching, the amount of interacting proteins can be varied continuously