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Project 1: Engineering Masks of the Future: Transparent, Highly Breathable, Reusable, and Smart
The US has the highest number of confirmed COVID-19 cases and deaths, more than five times those of the world’s average. The reasons include: 1) Overall adherence to community masking protocols often falling short of the necessary numbers needed to ensure low viral transmission rates across communities [1]; 2) The lack of effective and easily obtainable mechanisms for early detection of COVID cases.
The lack of sufficient adherence to masking guidelines arises, in part, from barriers to properly wearing masks, which include blocking of facial expressions, fogging of glasses, improper fitting, breathing difficulties, muffling of the voice, causing discomfort and pain, and being not eco-friendly, also, current masks cannot prevent people from inappropriately wearing masks, e.g., under the nose/mouth. Moreover, without accurate information of who has or likely has been infected, it is more than difficult to take appropriate mitigation measures and interventions that are needed to slow down the spread. Yet, current COVID-19 surveillance primarily relies on direct viral testing and is reactive rather than proactive. Such surveillance is often too late in preventing transmission from individuals with mild symptoms; not wearing the right masks appropriately further increases transmission from asymptomatic carriers. These situations often prove to be quite costly in healthcare settings, as illustrated by the high annual volume of healthcare-associated infections (HAIs), which cost billions of dollars every year (Methicillin-resistant Staphylococcus aureus, MRSA, is a well-known illness associated with HAIs, as is COVID-19 more recently) [2].
Masks and respirators with high filtration efficiency have been proven to be important tools for mitigating the spread of airborne illnesses such as COVID-19 and influenza. are necessary. However, it has been shown that improving the filtration efficiency of a mask also tends to increase the pressure differential (the decrease in pressure across the filter material divided by the surface area of the filter) [3], therefore making the mask/ respirator much less breathable. In many cases, this results in individuals being unable to wear high-filtration-efficiency masks (such as the N95 respirator) for an extended period, thereby putting them at greater risk for exposure. Here we propose to address both these problems with an integrated solution, the development of a novel transparent mask with smart biometric sensors. By designing a cartridge with an origami-like filter, the total surface area by which air can be pulled into the mask can be significantly increased, thus improving the breathability of the system. By integrating advanced sensing technologies into this mask, we provide a method for improved surveillance of symptoms for quicker diagnostic capability.
Project 2: Virtual Staples: A New Paradigm in Gastrointestinal Surgery
Anastomotic leakage (AL) has been one of the worst complications of esophagectomy and intestinal and colorectal surgery for over a century, as it leads to prolonged hospital length of stay (LOS), higher readmission and mortality rates, and significant additional costs both to the patient and the hospital. For example, high leak rates complicate the ~8 million colorectal surgeries/year alone worldwide (incurring additional LOS of +32.1 days and increased hospital costs of +$175,835 per patient, so the estimated total costs are ~$100 billion for colorectal surgeries alone and for gastrointestinal surgeries, ~$1 trillion). Where required, reoperation results in a negative impact on quality of life. The leak rate varies from 1-20% depending on the location, procedure and other risk factors and has not changed significantly for 40 years. These complications often result in increased cost of care, worse overall survival, poor quality of life, and oftentimes the need for further procedures.
A variety of factors have been implicated in anastomotic leaks—the most common include suture line ischemia, excessive tension, local sepsis, relevant underlying conditions, as well as surgeon-related factors. Despite significant interests, there is still no consensus on a universal mechanism nor a practical method for preventing anastomotic leaks.
Our solution:
Our solution:
The technical aspects of bowel anastomosis are designed and executed for the tissue biomechanics existing at the time of surgery. Our speculation is that this focus on the day of operation greatly underestimates the fatigue failure of tissues exposed to repetitive stresses over time; that is, fatigue failure caused by movement, deformation and luminal distension. Tissue fatigue and structural failure is generally observed during the remodeling phase of wound healing; that is, 7 to 10 days after the bowel anastomosis.
Anastomotic tension has been associated with increased risk of anastomotic leak, which can be in part attributed to the impairing of blood flow causing ischemic anastomotic breakdowns. However, few studies have addressed the roles of forces in the induction of gastrointestinal leaks not to mention the usage of such knowledge to devise minimally invasive prevention means. The recent success of the 3-dimensional staple design (ECHELON CircularTM) in reducing leaks by 61% without compromising perfusion compared to Medtronic DST Series EEA 2D stapler highlights the critical importance of averaging out compression forces.
We have invented no-perforation “virtual staples” (patent pending) to create gastrointestinal anastomosis that minimizes stress effects and reduces anastomosis leakage, which will significantly improve the quality of lives of patients who would otherwise suffer from gastrointestinal leaks and the associated morbidity and mortality. In this design, we replace the currently used staples with "virtual staples", each of which consists of a magnetic component and a complementary ferromagnetic component, both coated with biocompatible adhesives to be attached to one side of the tissue at the anastomosis. The magnetic forces will hold the two sides together without perforation. The virtual staples will reduce the pressure and stress concentration when the anastomosis is under tension, and hence significantly reduce the odds of anastomotic leakage occurrence. In one such embodiment, we employ magnet-metal bar couples all coated with biocompatible pectin or adhesive hydrogel to replace current staples. The magnetic forces deform the tissue into a curvilinear shape, which further secures the new “magnetic staples”. In another embodiment, we use a rectangular metal wire coupled with a magnet, both coated with biocompatible adhesive as the virtual staple. The magnet is slightly smaller in size than the rectangular wire so that the tissue sandwiched will deform into a curvy shape to increase the contact surface area between the two sides of the tissue. This new technique will potentially remove the complications that arise due to the high tension and poor blood flow associated with the previously used staples. A stapler is also designed to deploy these virtual staples. We will use finite element analysis to examine the stress distribution under the new condition and inform the optimization of the locations of the new no-perforation (punchless) biocompatible “magnetic staples”. The safety is secured by double protection from the pectin adhesive (patent at Brigham and Women’s Hospital) and “lock-in forces” of magnetic virtual staples as we expect that adhesion alone cannot eliminate leaks effectively.
Traditional bowel anastomosis relies on the use of sutures or staples, and comes with 5-40% chance of anastomotic leakage, depending on the location of the anastomosis and other patient and technical factors. Recent advances in biocompatible adhesives have not solved the issue of anastomotic leakage, probably because the mechanical properties of those adhesives are insufficient to prevent the consequences of excessive tension on gastrointestinal tissue. Our design will replace traditional staples without creating any perforation by employing both adhesives and ferromagnetic materials in conjunction, which significantly reduces the risk of tissue damage under repetitive loading or stress concentration near the staples.
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