Controlling Needle Navigation In Hydrogels For Automated Fabrication Of Vascular Like Channels

Abstract

Though tissue engineering has witnessed rapid advancement, integration of micro-vascular network in the constructs has remained an unsolved problem. Development of a fabrication technique to mimic the complex architecture of vascular network embedded inside a tissue engineered constructs is one of the limiting factors. Moreover, an ideal manufacturing technique must be automated and readily integrated/configurable at point-of-use with other unit operations. However, till date a satisfactory manufacturing modality which can integrate vascular network in tissue constructs in a readily automatable and configurable set-up has not been developed. As engineered constructs are soft, viscoelastic structures, development of automated fabrication modalities that can create hollow channels in such structures are inherently challenging. The present work hypothesizes that a robotically controlled needle navigation systems, such as the one used in needle biopsy procedures, can be used to steer a needle of given geometry inside a gel structure to create internal micro-channels resembling vasculature. newlineOutline of the Thesis: newlineThe outline of this thesis is as follows. newlineIn Chapter 1, a literature review is presented by brief discusses on recentinnovations in the biomanufacturing approaches applied to fabrication artificial vascular networks. Specially, different biofabicration procedure like 3Dbioprinting, electrospinning, micro-fluidics, micro-patterning etc. newlineChapter 2 develops the theoretical force modelling of needle-gel material interaction to estimate the forces required to navigate the needle inside the gel. newlineIn Chapter 3, the effect of insertion speed and needle diameter on frictional stress was evaluated. We use both rotational and non-rotational insertion analysis. The interaction function was found to depend on the material properties. The validity of the computational model was tested in an experimental model. newlineIn Chapter 4, influence of dissimilar insertion speed and the various types of vibrational frequencies on