4.5. Agar Gel Sample Preparation

Here, 0.6% agarose gel mimicking the stiffness of a brain tissue at 0.61 kPa elastic modulus ^{[40, 41]} with 3 mm thickness covered with a gauze mesh (CVS, Latex-free Gauze 5 CT) was used for the suturing experiment. A holder testbed, as shown in Figure 4, is designed. This testbed is aimed to clamp the samples perpendicularly to the planar needle workspace. Each testbed consisted of 1) two 3D printed pieces which could form a circular horizontal platform (radius = 41 mm) and a standing clamping frame (height = 11 mm), 2) a Petri dish (inner radius = 43 mm), and 3) glycerin-water solution (30 ml) (Glycerin Vegetable, Sanco Industries, Inc., Fort Wayne, IN). The clamping frame was positioned at the center of the Petri dish. Hence, adequate space was left for steering the needle in the suture study. Depending on the thickness of the sample, a non-sticky tape was inserted between 3D printed platform edges and Petri dish walls to close the gap and enhance the clamping functionality.