“Design Fabrication and Testing of a Novel Multifunctional Wound Healing Device

Abstract

Auxetic materials tend to exhibit stretching in the direction of the applied load as well as in the perpendicular direction. This may be an inherent property of the material, or it might be a particular structural characteristic, that confers it with auxetic properties. The auxetic properties of a rotating squares auxetic design has been utilized in tandem with a stretching mechanism to manufacture a device that offers the advantages of adjustable pore size and hence tunable drug delivery characteristics. The auxetic polyurethane film has been fabricated through the polymer casting technique. The ABS plastic mould for polymer casting was made through additive manufacturing. Stereolithography has been used for fabrication of the mechanism that controls pore size of the polymeric auxetic film. A laminate arrangement of the film and the mechanism has been devised, through which the movement of the mechanism controls the stretching of the auxetic film underneath. Results have been analyzed through image processing. It has been observed that a two-dimensional increase (in length and width) of the auxetic film takes place that corresponds to an increase in pore size of the film. Several mathematical correlations have been drawn up, and it may be concluded that the first factor controlling drug release kinetics would be the pore size of the film. In Phase I, we have explored the aspect of such a prototype, which has the potential of being used as a device for controlled drug delivery as well as a smart bandage that may enhance wound healing in a chronic wound treatment. Phase II of the research study continues along the same lines, but addresses and attempts to resolve the limitations inherent in the work previously done. In this study we have described the design and fabrication of a more life scale version of the wound healing device; this device caters to both the aspects of controlled drug delivery and exudate removal for chronic wounds. The device has been fabricated using a biocompatible polymer cast with structural features machined and modified through Laser Cutting. Subsequent tests have been conducted to account for the functionality of the device in controlled drug delivery. In this respect, two electronically actuated mechanisms (the lead-screw and pulley mechanisms) have been explored; these are miniaturized versions that fit compactly in the device structure and can be effectively controlled with a microcontroller set up. An auxetic polymeric film has been employed to limit the amount of drug being administered to the wound site.