1. A Novel Fat Removal Tool for Human Tissue Brandon Boles, Audrey Guyer, Ryan Mitchell, Krunal Parikh, Matthew Ringer Overview Background Information The Product LifeCell™ aims to alleviate safety concerns and improve the uniformity of their final allograft products by implementing a new fat removal system to replace the use of scalpels. Project Scope The scope of the project is to develop a functional prototype to remove adipose tissue from the dermal layer of donated human skin while also promoting technician safety and increasing functionality over the current process. Final Design Concept Generation Testing Plan Acknowledgements Testing of the final design was completed by the senior design team and technicians at LifeCell™. The final design was used in removing adipose tissue from human skin, and the new design was rated against the current scalpel method for each metric. Metrics LifeCell™ Corporation processes donated human skin tissue into allografts to be used in surgeries. Currently, scalpels (see Figure 1) are used to remove the fat layer from the dermis before further processing takes place. The current technique leads to a non-uniform product and worker injury. We would like to thank our sponsor, LifeCell™ Corporation, our advisor Dr. Anita Singh, as well as Mr. Beard and the rest of the Senior Design Staff. Prototype The final design is an 18,000 rpm motor with a torque rating of 771 g- cm. It is powered by 3-6 V of rechargeable batteries that are in circuit with a safety toggle switch and trigger button to initiate blade movement. Concept Selection Design Process First Generation This prototype featured a permanently installed stainless steel blade on the Remington™ HC5550. The prototype was tested on pork belly (Figure 3) to simulate donated human skin, as highlighted in green, and it was compared to a static blade (red). Second Generation This prototype featured a removable stainless steel razor blade held in place by a 3-pin system. A blade guard made of Delrin was installed above the blade mechanism to prevent adipose tissue from entering the device. This prototype was also tested on pork belly, as seen in Figure 4. Third Generation This prototype incorporated a trigger button mechanism to increase control and minimize potential harm to the technicians. This prototype was tested on human tissue at LifeCell™ in Branchburg, New Jersey (see Figure 5). Fourth Generation This prototype incorporated a modified stainless steel bumper below the blade in order to minimize the possibility of human error in terms of inflicting dermal damage during fat removal. As well, this prototype used a blade with curved edges to promote cutting. Validation MetricConstraint Technician Incidents: No puncture wounds Safety Technician Fatigue: 50% reduction Safety Fat Removal: 100 % fat removal Functionality Dermal damage: 80% reduction Functionality Cost: $20 disposable costCost-efficient In order for the design to be implemented, it must be superior in comparison to the current scalpel technique. A qualitative feedback survey was administered to the technicians at LifeCell™. The survey includes questions on -ease of use-learning curve -comfort -functionality-dermal damage The feedback from LifeCell™ was used to validate the final design against the project metrics. Concept A (see Figure 2) was selected based on discussions with LifeCell™. This device incorporates a bumper system that will protect the dermal layer, an electrical component that reduces worker fatigue, longitudinal motion that will reduce worker injury, a blade replacement mechanism, and a trigger to activate the device. The stainless steel blades have a serrated cutting edge and are held in place by a 3-pin system. The blades are removable by unscrewing the stainless steel bumper. See Figure 6 for a model of the final design. Path Forward After hand-off of the final prototype to the sponsor, the path forward will be to produce an autoclavable replica for evaluation and eventual commercial use by technicians in the class 100 cleanrooms at LifeCell™. BMEG450: Senior Design, Fall 2013 Figure 2: Concepts A, B, and C Figure 1: Scalpel blade and handle Figure 3: Pork Belly test Figure 4: Blade with pin system Figure 5: Visit to LifeCell Table 1: Metrics for the fat removal tool Metrics were developed in consultation with LifeCell™ to address the project constraints (see Table 1). Figure 6. Final design A B C