1. You study mucus. What exactly is mucus? How does it benefit our bodies and us?
Mucus is a biological gel that lines all internal surfaces of the body that are not covered by skin such as the eyes, nose, lungs, stomach, and female reproductive tract. It acts as a protective barrier on these surfaces by keeping them hydrated and by keeping out harmful microbes, dust, or other small foreign particles. For perspective, the surface area covered by mucus amounts to more than 2000 square feet or approximately the size of a tennis court, and the body needs to produce about a gallon of mucus every day to keep this lining intact and functioning properly!
The main structural components of mucus are glycoproteins called mucins. Mucins are shaped like bottlebrushes, with proteins making up the core and densely packed sugar chains making up the brush. These sugar chains can interact in many ways with a variety of different protective molecules, such as those from the immune system and beneficial microbes, and this interaction is essential for keeping us healthy. In fact, mucus is a major ecological niche for microbes, and there are trillions of microbes that live on and in our bodies (more than the number of human cells!) Most of these microbes live inside the mucus of the digestive tract, and serve numerous beneficial functions such as aiding in food digestion and production of vitamins. In addition, over millions of years mucus has evolved the ability to keep a number of problematic pathogenic microbes in check, and prevent them from causing damage by keeping their population sizes manageable.
Many diseases are related to mucus failing to properly perform these important functions. For instance, when mucus is not produced in large enough quantities, the underlying cell layer can become dehydrated, cracked, and more accessible to environmental toxins and viruses. This manifests frequently in the eyes as dry-eye syndrome, and in the nose an insufficient mucus layer can result in difficulty smelling. In addition, patients with cystic fibrosis have sticky mucus that is more difficult for the lungs to clear and renew. This lower turnover rate can make it easier for bacteria to proliferate unchecked and potentially develop biofilms, which are complex and organized bacterial cell communities capable of sophisticated tasks like communication and defense against antibiotics. So, one important picture that is emerging is that in addition to all its other impressive biological functions, healthy mucus is effective at preventing the formation of potentially pathogenic biofilms.
2. Is there any truth behind the classic claim that eating your snot / boogers is good (or bad) for you?
To our knowledge, there are no scientific studies addressing this issue directly. In order to do so, there would need to be an experiment set up along the lines of having two groups of randomly selected subjects: a control group that never eats their boogers and a treatment group that eats their boogers with a certain regularity. Over a prolonged period of time, say months or years, specific indicators of overall health (such as blood pressure, body temperature, etc..) would need to be monitored, and these indicators would need to be significantly better in the treatment group than the control group in order for this claim to be considered scientifically sound. There are perhaps several reasons why such an experiment doesn’t seem likely or feasible in the immediate future. So, most likely this claim is an excellent example of how popular information can claim to be founded in scientific evidence, but in reality has been misconstrued to such a degree that it is no longer backed up by the real conclusions of the study it is supposedly based on.
In general there is a lack of publicly available scientific information on crucial facets of mucus function, including in basic educational literature such as biology textbooks. One of our main goals is to communicate our findings about mucus in an accessible enough way to begin to close this gap between the public and scientific perception of mucus. Too often mucus is thought of as just snot; a “gross” waste product, while we think of it as a fascinating material with many important roles in biology, particularly in human health. The truth is that only people who understand the significance of mucus will read and implement our science. Therefore, the fruitful development of the mucus research field goes hand in hand with the education of the people.
So, all this to say that although eating your boogers might not directly make you healthier, having mucus in our bodies is absolutely invaluable for human health, and our goal is for everyone to eventually understand why this is the case.
3. How does an engineer end up studying mucus for a living?
It is striking to me that something as common and understudied as mucus has such a profound role for our health. I am committed to the study of mucus because I am convinced it could help us solve some really essential and vexing problems. For instance, one of the main challenges of creating drugs is designing in them in such a way that they are able to reach their target tissues. Since mucus lines so much of the interior surface of the body, its role as a barrier can actually result in it preventing drugs from reaching their targets. So, if we can understand which properties of molecules enhance their transport through mucus, we can design better and more effective drugs for a huge variety of diseases. Moreover, my lab and others around the world are thinking about how to engineer mucins and mucus to control problematic pathogens inside and outside of the body. This is a particularly exciting field of study since it would allow us to treat infections without needing to use antibiotics, thereby reducing the threat of antibiotic resistant germs. In addition to problematic pathogens, we also hope to leverage mucus to domesticate microbes that can help humans thrive on the planet. For instance, engineering mucus /microbe interactions to make us more salt tolerant would alleviate a huge amount of the strain on global drinking water reserves. As a final example, we are beginning to understand how mucus and its mechanical and biochemical properties can be leveraged as biomarkers for disease. In this way, we could build powerful, safe, and simple diagnostic tools for identifying diseases globally, which would also accelerate treatment of these diseases by improving our understanding of their etiologies.
4. Can you create synthetic mucus? What uses might it have?
It turns out that recreating the impressive biological and mechanical properties of native mucus using synthetic materials is tremendously challenging, but it is something that my lab and others around the world are actively trying to do. The process of purifying mucin from native sources of mucus is time consuming and costly. Therefore, to be able to develop large-scale treatments involving mucus, the design of well-functioning synthetic mucins will be crucial. The uses of such a tool would be enormous: we could design properly lubricating eye drops for people with dry-eye syndrome, stop the growing threat of antibiotic resistant germs by developing mucin pathogen therapies, stop bacteria that naturally colonize your body, such as candida and strep, from causing life-threatening infections, and so much more.
5. What are the broad applications / benefits to your research? Why would an aspiring engineering consider exploring biogels? What are the major questions, opportunities?
One of the main challenges of creating drugs is designing in them in such a way that they are able to reach their target tissues. Since mucus lines so much of the interior surface of the body, its role as a barrier can actually result in it preventing drugs from reaching their targets. So, if we can understand which properties of molecules enhance their transport through mucus, we can design better and more effective drugs for a huge variety of diseases. Moreover, my lab and others around the world are thinking about how to engineer mucins and mucus to control problematic pathogens inside and outside of the body. This is a particularly exciting field of study since it would allow us to treat infections without needing to use antibiotics, thereby reducing the threat of antibiotic resistant germs. In addition to problematic pathogens, we also hope to leverage mucus to domesticate microbes that can help humans thrive on the planet. For instance, engineering mucus /microbe interactions to make us more salt tolerant would alleviate a huge amount of the strain on global drinking water reserves. As a final example, we are beginning to understand how mucus and its mechanical and biochemical properties can be leveraged as biomarkers for disease. In this way, we could build powerful, safe, and simple diagnostic tools for identifying diseases globally, which would also accelerate treatment of these diseases by improving our understanding of their etiologies.