3D Printing of Novel Anti-bacterial Polymer Composite Auxetic Structures for Biomedical Meshes

Abstract

Hernia repair treatment is one of the common surgical procedures globally. Increasing prevalence of surgeries has led to many complications in the human body. Successful treatment of hernia repair is necessary in preventing critical outcomes such as foreign body rejection, lack of biocompatibility and high adhesion to the abdomen wall. Ideal mesh for hernia repair is still in debate. 3D Printing of hernia meshes can reduce many surgical complications due to its long-term benefits. Mesh size, shape, material properties, weight to volume ratio, thickness and flexibility etc. can be compared using the Additive Manufacturing technique. Auxetic structures are metamaterials having Negative Poisson’s Ratio (NPR). They possess higher loading and stretching effect as compared to conventional meshes. Polypropylene is of greater interest for surgical 3D Printed hernia meshes because of its non-biodegradable nature. Pore size and thickness of the meshes are the major controlling parameters for the 3D Printed auxetic and non-auxetic hernia meshes. Coatings of 3D Printed hernia meshes using ZnO NPs enables the antibacterial properties in the hernia meshes. The 3D Printed meshes are also used in anti-bacterial applications avoiding systematic toxicity. The selected 3D Printed auxetic and non-auxetic hernia meshes were characterized using the Fourier Transform Infrared (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM) and Optical Microscopy. The mechanical strength and stability can be determined using the Dynamic Mechanical Analysis (DMA). Temperature and frequency sweep analysis were performed respectively. In UTM, based on the stress-strain curves breaking strain, maximum force and stiffness were computed. Anti-bacterial activity using the broth dilution method confirms the antibacterial effects of the coated auxetic and non-auxetic hernia meshes. Useful information for the selection of possible medical applications for auxetic and non-auxetic meshes and the design process of 3D printed implants are provided. Therefore, the 3D Printed coated nanocomposite auxetic mesh can be a promising candidate for hernia repair in the future.