China
Africa
Explore chapters and articles related to this topic
Modular Biomimetic Drug Delivery Systems
Published in Severian Dumitriu, Valentin Popa, Polymeric Biomaterials, 2020
Carmen Alvarez-Lorenzo, Fernando Yañez-Gomez, Angel Concheiro
Recently, gecko-inspired (geometric-based) adhesives have been developed to provide nanoparticles with enhanced mucoadhesion. The toe pads of geckos and other lizards are covered with millions of tiny branching hairs that enable so close a contact with the substrate that intermolecular forces result in excellent adhesion, but are still reversible (Barnes 2007). Reusable tapes that adhere equally well in wet and dry conditions combine the microstructure of gecko pads with the performance of the protein glue of mussels (Lee et al. 2007). Macromolecules can be conjugated to synthetic carriers using the mussel adhesive protein (Lee et al. 2009). A gecko-inspired adhesive based on poly(glycerol sebacate acrylate) (PGSA) with regulable elastic and biodegradable properties has been developed for specific tissue application and for being doped with growth factors or drugs (Mahdavi et al. 2008). This tape-based tissue adhesive platform is claimed to have application in medical therapies ranging from suture/staple replacements, waterproof sealants for hollow organ anatomoses, mesh grafts to treat hernias, ulcers, and burns, and hemostatic wound dressings. On the other hand, silicon nanowire-coated beads can be designed to generate strong bioadhesive forces based on geometric features alone (similar to the interlocking interaction of the Velcro hook-and-loop fasteners). The nanowires were prepared to perfectly fit the space between the microville of Caco-2 cells (Figure 4.3). The interdigitation of the nanowires and the microvilli led to enormous area of contact between the nanoparticles and the cells, and notably prolonged the retention time of the nanoparticles on the cell culture under flow of mucous (Fischer et al. 2009).
Method for evaluating the snagging propensity of roofing membranes in buildings by roosting bats
Published in Building Research & Information, 2020
E. A. Essah, S. J. Russell, S. D. Waring, J. Ferguson, C. Williams, K. Walsh, S. Dyer, R. Raynor
Therefore, for practical reasons, a reproducible synthetic material that has the advantage of being robust, reproducibly manufactured and readily applied by multiple laboratories was used. One side of Velcro® consists of a woven base fabric from which small filamentous hooks project. It was observed that the projecting hooks of the Velcro® structure (Figure 6) crudely mimic a bat claw in terms of curvature and stiffness. Initial evaluations with fine pins and needles were also made, but none mimicked the claw action as well as the Velcro®. Although this might be a potential limitation regarding how accurately the bat claw was mimicked, use of the natural material was impossible as it would have required the killing of a number of bats which are a protected species. The use of Velcro, however, provided significant accuracy within limits to the nature and movement of the bat claw.