RESUMO
Fibrin-based gels are used in clinics as biological glues but their application as 3D cellularized scaffolds is hindered by processing and stability issues. Silicification of fibrin networks appears as a promising strategy not only to address these limitations but also to take advantage of the bioactivity of Si. However, it raises the question of the influence of silica sources on fibrin self-assembly. Here tetraethoxysilane, aminopropyltriethoxysilane and silica nanoparticles were used to design hybrid and nanocomposite fibrin-based hydrogels. By varying the concentration in silica source, we could evidence two regimes of interactions that depend on the extent of inorganic condensation. These interactions modulated the fibrillar structure of the fibrin network from more than 500 nm to less than 100 nm. These nanofibrillar hydrogels could exhibit higher mechanical properties than pure fibrin while preserving their capacity to support proliferation of myoblasts, opening promising perspectives for the use of fibrin-silica constructs in tissue engineering.
Assuntos
Fibrina/química , Hidrogéis/química , Dióxido de Silício/química , Engenharia Tecidual/métodos , Alicerces Teciduais , Animais , Proliferação de Células/efeitos dos fármacos , Dicroísmo Circular , Cinética , Camundongos , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Mioblastos/efeitos dos fármacos , Miofibroblastos/metabolismo , Nanopartículas/química , Nefelometria e Turbidimetria , Propilaminas/química , Reologia , Silanos/química , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
In this work we present a novel, inductance-based system to measure and control the motion of bellows-driven continuum joints in soft robots. The sensing system relies on coils of wire wrapped around the minor diameters of each bellows on the joint. As the bellows extend, these coils of wire become more distant, decreasing their mutual inductance. Measuring this change in mutual inductance allows us to measure the motion of the joint. By dividing the sensing of the joint into two sections and measuring the motion of each section independently, we are able to measure the overall deformation of the joint with a piece-wise constant-curvature approximation. This technique allows us to measure lateral displacements that would be otherwise unobservable. When measuring bending, the inductance sensors measured the joint orientation with an RMS error of 1.1 °. The inductance sensors were also successfully used as feedback to control the orientation of the joint. The sensors proposed and tested in this work provided accurate motion feedback that would be difficult to achieve robustly with other sensors. This sensing system enables the creation of robust, self-sensing soft robots based on bellows-driven continuum joints.
