From Crap to Cure: The Story of Fecal Transplants
C. difficile had Meg Newman's number; it had struck her 18 different times beginning in 1985. The bacterial infection takes over the gut bringing explosive diarrhea, dehydration, weight loss, and at its worst depletes blood platelets. It causes nearly 30,000 deaths each year in the U.S. alone.
"I was one sick puppy as that point and literally three days after the transplant I was doing pretty well, day four even better."
Meg knew these statistics not just from personal experience but also because she was a doctor at San Francisco General Hospital. Antibiotics had sometimes helped to treat the infection, but it never quite seemed to go away. Now, "It felt like part of my colon was sort of sliding off as I had the bowel movement." On her worst day she counted 33 bowel movements. It was 2005 and she knew she was at the end of her rope.
Medical training had taught Meg to look at the data. So when antibiotics failed, she searched the literature for other options. One was a seemingly off-the-wall treatment called fecal transplants, which essentially gives poop from a healthy person to one who is sick.
Its roots stretch back to "yellow soup" used to treat dysentery in China nearly two thousand years ago, in which ancient Chinese treaters would combine stool with liquid, mash it up, and administer it. The approach also is commonly used in veterinary medicine today. However, there were only about three papers on its use in humans in the medical literature at that time, she recalls. Still, the logic of the intervention appealed to her.
The gut microbiome as a concept and even a word were not widely known fifteen years ago. But the idea that the microbial community in her gut was in disarray, and a transplant of organisms from a healthy gut might help restore a more normal ecology made sense. And besides, the failure of standard medicine left her few options.
Meg spoke with a colleague, gastroenterologist Neil Stollman, about a possible fecal microbial transplant (FMT). Only a handful of doctors in the U.S. had ever done the procedure; Stollman had tried it just once before. After conversation with Newman, he agreed to do it.
They decided on Meg's partner Sherry as the donor. "I try very hard to use intimate sexual partners as the donor," explains Stollman. The reason is to reduce disease risk: "The logic there is pretty straightforward. If you have unprotected sex with this individual, in a monogamous way for a period of time, you have assumed pretty much any infectious risk," like hepatitis, HIV, and syphilis, he says. Other donors would be screened using the same criteria used to screen blood donations, plus screening for parasites that can live in stool but not blood.
The procedure
Martini aficionados fall into two camps, fans of shaken or stirred. In the early days the options for producing of fecal transplants were a blender or hand shaken. Stollman took the hands-on approach, mixing Sherry's fecal donation with saline to create "a milkshake in essence." He filtered it several times through gauze to get out the lumps.
Then he inserted a colonoscope, a long flexible tube, through the anus into Meg's colon. Generally a camera goes through the tube to look for polyps and cancers, while other tools can snip off polyps and retrieve tissue samples. Today he used it to insert the fecal "milkshake" as high up the colon as he could go. Imodium and bed rest were the final pieces. It works about 90 percent of the time today.
Meg went home with fingers crossed. "And within about two weeks things just slowed down; the diarrhea just stopped. I felt better so my appetite was better." The tide had turned, though it would take months to slowly repair the toll taken on her body from disease and antibiotics.
Then in 2011 another serious medical challenge required heavy use of antibiotics and Meg's C. difficile came roaring back; she needed a second FMT. Sherry had a bad sinus infection and had been on antibiotics, so that ruled her out as a donor. Red, Meg's godson, volunteered. He was twenty-one and had little or no exposure to antibiotics, which can harm friendly bacteria living in the gut.
"I was one sick puppy as that point," Meg recalls, "and literally three days after the transplant [from Red] I was doing pretty well, day four even better. It was unbelievable." It illustrated that donors are not the same, and that while an intimate partner may be the safest option, it also may not be the most efficacious donation in terms of providing missing parts of the microbial ecosystem.
Going mainstream
By then, FMTs were starting to come out of the shadows as more than just a medical oddity. One gigantic milestone in changing perceptions was a Dutch study on using the procedure to treat C. difficile that was published in January 2013 in the New England Journal of Medicine. "That was the first trial where people said, look this isn't voodoo. This wasn't made up; it really worked," says Colleen Kelly, another pioneer in using FMTs to treat C. difficile and a researcher at Brown University. A single dose was successful more than 80 percent of the time in resolving disease in patients who had failed multiple regimens of antibiotics.
Charlatans pounced on the growing interest in the microbiome, promoting FMT as a cure for all sorts of ailments for which there was no scientific evidence. The FDA stepped in, announcing it would regulate the procedure as a drug, and essentially banned use of FMTs until it wrote regulations. But the outcry from physicians and patients was so great it was forced to retreat and has allowed continued use in treating C. difficile albeit on an interim regulatory basis that has continued since 2013.
Another major change was the emergence of stool banks, modeled on blood banks. The most widely know is OpenBiome, established in 2012 as a nonprofit by young researchers at Harvard and MIT. It aimed to standardize donation of stool and screening for disease, and package them in frozen form for colonoscopic delivery, or pill form. It greatly simplified the process and more doctors became willing to use FMTs to treat C. difficile. Today, some gastroenterologists specialize in administering the transplants as a feature of their practice.
To be sure, there have been some setbacks, including a transplant between family members where the recipient became obese, likely in part because of bacteria in the material she received. The same thing has occurred in studies in mice. And last year, an elderly man died from a toxic strain of E. coli that was in material provided by a stool bank. That caused the FDA to add that pathogen to the list of those one must screen for in products designed for use as fecal transplants.
Cost remains an issue. OpenBiome charges $1500-$2000 per transplant dose, depending on whether a frozen or pill form of the product is used. And that is likely to go up as the FDA increases the number of diseases that must be screened for, such as the virus that causes COVID-19, which is present in feces and likely can be transmitted through feces. Most insurance companies do not cover FMTs because no product has been formally approved for use by the FDA.
One of the greatest treatment challenges is making the correct diagnosis, says physician Robin Patel, who initially treated patients at the Mayo Clinic in Rochester, Minnesota but now spends most of her time there developing new diagnostics. Many things can cause diarrhea and the simple presence of the organism does not mean that C. difficile is causing it. In addition, many people are colonized with the bug but never develop symptoms of the disease.
Patel used the expensive tool of whole genome sequencing to look in great detail at C. difficile in patients who were treated with antibiotics for the infection and had recurrent diarrhea. "Some of them, as you might predict, were getting their symptoms with the same exact strain [of C. difficile] but others were not, it was a different strain," suggesting that they had been reinfected.
If it is a different strain, you might want to try antibiotics, she says, but if the same strain is present, then you might want to try a different approach such as FMT. Whole genome sequencing is still too slow and expensive to use in regularly treating patients today, but Patel hopes to develop a rapid, cost-effective test to help doctors make those types of decisions.
Biotech companies are trying to develop alternatives to poop as a source for transplant to treat C. difficile. They are picking and choosing different bacteria that they can grow and then combine into a product, to varying degrees of success, but none have yet crossed the finish line of FDA approval.
"I think [the future of FMTs] is going to be targeted, even custom-made."
The FDA would like such a product because it is used to dealing with small molecule drugs that are standardized and produced in batches. Companies are pursing it because, as Kelly says, they are like sharks "smelling money in the water." Approval of such a product might cause the FDA to shut down existing stool banks that now exist in a regulatory limbo, leaving the company with a monopoly of exclusive rights to the treatment.
Back when Meg received her first fecal transplant, the procedure was so obscure that the guidelines for treating C. difficile put out by the American College of Gastroenterology didn't even mention FMT. The procedure crept into the 2013 revision of those guidelines as a treatment of last resort. Guidance under review for release later this year or early next year will ease use further but stop short of making it a first option.
Stollman imagines a future holy grail in treating C. difficile: "You give me a stool specimen and I run it through a scanner that tells me you have too much of this and too little of that. I have a sense of what normal [microbial composition of the gut] should be and add some of this and subtract some of that. Maybe I even give you some antibiotics to get rid of some of the bad guys, give you some probiotics. I think it is going to be targeted, even custom-made."
His complete vision for treating C. difficile won't arrive tomorrow, but given how rapidly FMTs have become part of medicine, it is likely to arrive in pieces and more quickly than one might think.
About five years ago Meg discovered she had an antibody deficiency that contributed to her health problems, including vulnerability to C. difficile. She began supplementation with immunoglobulin and "that has made a huge difference in my health. It is just unbelievable how much better I am." She is grateful that fecal transplants gave her the time to figure that out. She believes "there's every reason to consider it [FMT] as a first-line treatment and do the studies, ASAP."
Last minute holiday gifts for the bio-inspired
“Merry Christmas! Isn’t it fun to say Merry Christmas to everyone? Time for a party and presents and things that make children happy and give their hearts wings!” go the lyrics of the popular Christmas poem. But adults (of various religions) need their gifts this time of year, too. For the biologically inspired big children, the process of finding the right fit can be daunting. To inform your choices in both conventional and unconventional ways, Leaps.org is presenting a roundup of the coolest bio-products related to health, nutrition, gaming, lifestyle and more.
AYO Circadian Light Therapy Wearable
We don’t hear it tick, but we have our own clock inside our body–more precisely, circadian clocks. Our cells contain tiny molecular clocks that keep track of our circadian rhythms, or our sleep and metabolism pattern and activity levels, on a daily basis. Chronic circadian disruptions can lead to sleep disorders, poor energy levels, weight gain, lousy mood, and sped-up aging, as well as increased risk for every “modern” disease out there, from diabetes to cancer.
Now, high-tech glasses have been developed that attempt to mimic the benefits of sunlight. In the morning and afternoon, these glasses shed blue light into your eyes to stimulate the master clock at the base of your brain for less drowsiness. The technology's design draws from an area of research, chronobiology, that received a Nobel Prize in 2017 and has become increasingly active in recent years.
“We have been developing and testing the AYO Circadian Health solution for the past five years in collaboration with some of the world's leading experts and researchers in chronobiology, light therapy and health,” said Alexander Dimitrov, co-creator of AYO. “We have done studies with over 25,000 participants, and over one million light sessions,” Dimotrov continued, partnering with institutions such as Mount Sinai Hospital, City of Hope and the U.S. Department of Defense.
The technology could fundamentally reshape the way we view sleep, health and our daily calendars. And, when connecting to a mobile app, the glasses could minimize circadian disruptions for travelers between conflicting time zones.
($269)
myDNAge Test
It's not easy for many people to break free of their attachment to the concept of chronological age, which counts years by how many times we’ve circled the sun since the day we were born. Society lumps us all into one age bracket according to our date of birth but, lately, research is suggesting that we should do some serious deconditioning. According to these studies, the more accurate measure is your biological age, a measurement based on various biomarkers of the body’s overall health and resilience, regardless of your calendar age.
If you want to find out your “true” biological age, myDNAge is a test that focuses on epigenetics, or patterns of changes in DNA methylation, with some initial research pointing to its accuracy. It offers a snapshot of your epigenetic age as well as key biomarkers related to your metabolism, risk of Alzheimer's and more, according to Xiaojing Yang, group leader of epigenetics at myDNAge. “You can perform tests six to 12 months [apart] to track the impact of lifestyle changes,” Yang said. The kit could be a useful tool both for citizen scientists and biohacking veterans.
($299 for one kit–Use code NEWYEARNEWME to receive 50% off a second kit)
Prairie Sky Yak Cheese
Do you love cheese? Do you love exotic cheese? Do you have an interest in preserving biological and genetic diversity? If you answered yes to all three questions, yak cheese was made for you. This type of cheese typically comes from a free-range yak living 13,000 feet above surface level in the Tibetan Himalayas, a relative of the endangered Wild yak. (North America is home to at least 5,000 registered yaks.)
“When I learned that we had a piece of rare biodiversity to be preserved for future generations, I realized that the yak in North America needed a job,” said Nicole Geijer Porter, president of World Heritage Yak Conservancy (WHYC), an organization formed to protect heritage yak “If an animal cannot be beneficial to the rancher in some way, exclusively as pets and lawn ornaments, they will go extinct. Raised for meat they are often hybridized with cattle to grow bigger and faster, so they will also go extinct,” said Porter, an epigeneticist turned yak herder.
Each slice of cheese and piece of butter supports the genetic testing and tracking of Tibetan yak. (You can become a member of WHYC through the Adopt-A-Yak program). “This project is also of biological importance because of the low methane emission research on yak, and the high nutritional content of the milk and cheese,” said Porter.
As for flavor, the Prairie Sky Yak Gruyere is a semi-hard cheese with a nutty taste sometimes compared to chocolate; Tomme de Savoie is a semi-soft Alpine cheese reminiscent of a washed rind muenster; and the Yak Cheddar is made with yak milk following the classic English recipe from Wells Cathedral, with earthly and pungent flavors.
(Various prices; $59.95 for the Three Yak Cheese Flight Gift Box, $139.95 for the Regional Himalayan Yak Cheddar Gift Basket and more)
Bite Toothpaste Bits
The price of a healthy smile is steep. Each year over one billion plastic toothpaste tubes are thrown out, over 50 Empire State Buildings worth of these tubes end up in landfills or oceans, and many animals suffer and die each year in cruel tests for improving oral care in people.
Sustainable oral care is both an act of self-love and giving back to the environment. Bite is a toothpaste that boasts about its green practices for a reason: it uses recyclable glass bottles with aluminum lids that break down into sand after they’ve been used. For shipping, Bite uses kraft envelopes padded with recycled and compostable newspapers, and its boxes are made of fully recycled, corrugated cardboard and sealed with paper tape. Bite refills come in 100% home compostable pouches every four months (still no plastic).
Sustainability aside, there may be an element of fun to Bite – as you brush, a mint foam forms “like magic,” the company claims.
Fractional Laser Treatment for Skin
The environment is hard on our skin: from ultraviolet rays to pollution, a constant oxidative war is waged upon it, leading to loss of collagen and damage to the barrier function of the skin. A fractional laser treatment is a type of laser skin resurfacing procedure that essentially traumatizes the skin – in a good way - through subjecting a small area of it to tiny amounts of laser energy. The laser penetrates the second layer of skin, the dermis, leading to skin exfoliation, which stimulates collagen and elastin production.
The treatment may help with soothing acne scarring, correcting uneven skin tone and texture, and reducing wrinkles and fine lines, sun damage and age spots. Recent research suggests the fractional laser can help with improving skin elasticity and reducing the amount and depth of wrinkles, though there’s little to no evidence for any benefits for eyebags, dark circles, discolorations within the eye area and water retention.
(Typically, a single fractional laser treatment costs $750 for a small area, $1500 for a full facial treatment, and $2000 for full face.)
Gadgets and Apps to Measure Your Heart Rate Variability
Heart rate variability may sound like a condition that requires immediate medical treatment, but the more you have of it, the better for your health. Although you may think of the heart as a steadily beating metronome, there are actually small differences in the amount of time between each beat. These differences are called HRV, and having more HRV has been linked to better fitness and fewer diseases.
HRV is easy to measure with a range of gadgets on the market, including Fitbits and Oura Rings. Which product floats your boat is a matter of personal preference, but the Polar H10 chest strap offers some advantages. For example, you can measure your HRV with the Polar H10 while walking around, unlike some devices that require you to stay still while taking a reading.
Plus, the Polar sensor pairs with free apps such as Elite HRV that are great for tracking how your HRV changes over time. "HRV really helps you gauge if you're moving in a positive or negative direction" with your health, says Jason Moore, the CEO and founder of Elite HRV and Spren. Have fun experimenting over the holidays with different lifestyle habits that are associated with higher HRV, some studies show, such as intermittent fasting, regular exercise and just getting more sleep.
($89 for the Polar H10, $0 for the Elite HRV app)
FoodMarble AIRE2
Its predecessor, FOODMarble AIRE1 was a pocket-size breath-testing device that measured hydrogen on the breath. More hydrogen means less digestion, and the AIRE1 used advanced breathalyzer technology to figure out what exactly is going on with the gut. Now, the company has launched FoodMarble AIRE2, which also measures methane alongside with hydrogen. High levels of methane in the body may cause abdominal pain, bloating and constipation, cirrhosis of the liver and chronic pancreatitis. The AIRE2 also comes with haptic feedback to make it easier to use.
Research suggests that these breath tests are valid as at-home diagnostic tools for many digestive conditions. To get the most accurate results, though, it’s important to closely follow the recommended protocol - for example, you can’t eat or drink anything for 10 to 12 hours before the test.
($229)
Adventurist Backpack’s Classic Backpack
The Classic backpack is a perfect option for life science aficionados who enjoy getting outside and exploring in nature. Padding in the front and back provides extra protection for camera gear, laptop, and other electronics, and it's completely water-resistant so you can get outside in winter weather.
Nobility points: Adventurist Backpack Co. is partnered with national non-profit Feeding America, and every backpack sold helps provide 25 meals to families in need across the U.S.
($65)
This Saves Lives
Speaking of nobility points, you could load your new backpack with a food choice that helps feed others as well. In 2013, actors Kristin Bell, Ryan Devlin, Ravi Patel and Todd Grinnell teamed up to start This Saves Lives, which makes power bars full of vitamins and nutrients, and the company has a unique business model: for every bar you buy, a packet of food is sent to a child in need. In addition to offering essential nutrients, the bars are non-GMO, kosher and gluten-free. Note: This Saves Lives is owned by the same company, GOOD Worldwide, that owns Leaps.org.
(Wild Blueberry & Pistachio bars, $23.99)
NADI X Pants
Even if you’re a yoga zealot enjoying the benefits to your strength, balance and flexibility, chances are you're performing the movements sort of askew. Wearable technology wants to improve your yoga posture and these sleek yoga pants called NADI X have subtle electronic sensors that track how you place your hands, rotate your hips, and align your back. The leggings use haptic feedback (or vibrations on your skin) to slowly guide you into correct alignment. You can also combine the wearable with an app that contains 40 poses and fitting music. Even if you aren't into yoga, you could use the pants for a perfect stretching session. If you do use it for yoga poses, the pants will “speak” to you, letting out a soothing "om" sound once everything is perfect.
Meta Quest Pro VR headset
When it comes to perfecting virtual reality (VR), the Meta Quest Pro VR headset is one step ahead the rest. In a vibrant 3D virtual space, your Meta avatar has the ability to translate your real-life facial expressions into the virtual realm so the experience can feel more personal, while controllers track your movement and use haptic feedback to translate your hand gestures and finger actions into VR as well. Unlike its Quest 2 headset, Meta markets this Quest Pro headset, which was just released in October, as a great tool for work and business meetings, but you can also use it to play games, watch movies, or download fitness apps or mental-health related apps – some of which are designed to help you get boxing workouts with long-distance friends, fight your fear of heights or meditate in outer space.
Rouge Sur Mesure Custom Lip Color Creator
Beauty and artificial intelligence (AI) complement each other well in the new Yves Saint Laurent lip personalized color – which wants to put the final nail on the coffin of generic lipsticks. This is a lipstick printer at its core. You pair a device to your smartphone and then insert three lipstick cartridges into the base, each of which comes with a color palette (all four could create up to 4,000 lipstick shades). Particularly charming is the fact that you can take a photo of your outfit, and the app will suggest shades that match or clash it.
($299, cartridges $89 each)
Dairy-Free Cream Cheese and Meatless Breakfast Patties
On the environmental front again, meatless patties and dairy-free cream cheese constitute conscientious and delicious choices for vegans, vegetarians and pretty much anyone else. Chicago-based Nature's Fynd is worth checking out. It uses a microbe named Fusarium strain flavolapis, which has origins in an acidic hot spring at Yellowstone National Park.
“We use this remarkable microbe to grow Fy — a nutritional fungi protein that’s made into a wide variety of delicious and sustainable foods,” says Karuna Rawal, Nature’s Fynd CMO. Fy is grown via a breakthrough fermentation process using a fraction of the water, land, and energy compared to traditional protein sources.
It’s a sustainable way to grow food for Earth’s population,” but Nature’s Fynd isn’t just concentrating on Earth. The company recently partnered with NASA to send Fy to space. “As long as there’s an appropriately controlled environment, we can grow Fy anytime, anywhere. It could be a nutritious food source for astronauts on deep space missions," said Rawal.
CBD Oil
Biologically curious people may be especially interested in trying cannabinoid (CBD) oil. CBD is a natural and safe substance found in cannabis, which has been found to tackle anxiety and depression, reduce symptoms of post-traumatic stress disorder, help manage chronic pain and migraines, improve sleep patterns, and keep panic attacks at bay. Kanibi’s Isolate CBD Oil Tincture is a good choice as it is cinnamon-flavored and made in an FDA-inspected facility.
($109--25% off on your first order)
Govee RGBIC Floor Lamp
Another winner for anyone who's been hearing about the health benefits of obeying your circadian rhythms: "RGB" lights, or red-green-blue lights that can be operated by remote control to shine bright blue light during the day and then, with a few touches of your phone, bathe you in warmer, red light to get you ready for bed. Look for RGB bulbs to stick into the light fixtures you already have, or you could opt for the Govee floor lamp that syncs with an app on your phone (or Alexa) for circadian color changing. You can also put it on party mode and watch it shift across 16 million color shades in response to the rhythms and beats of Cuddle Up, Cozy Down Christmas and Hanukkah Oh Hanukkah.
($99)
PackPoint
If you suffer from packing anxiety (or incompetence), an app may take away the pain. PackPoint is an app that builds your packing list according to trip type, activities and weather. You add your trip details, select activities (fancy dinner, business meeting, or even workout are some examples), and PackPoint tells you what you need to bring to your destination. The app is free, but upgrading to Premium for a small fee lets you add your own activities and packing list items.
(Free, Premium Package $2.99)
Eternity Rose
Roses symbolize love, passion, innocence, friendship, and the disarming power of natural beauty. They wilt fast, though, and their spectacle is an unsettling reminder of the fragility of beauty and existence. Unless you dip the rose in 24 karat gold.
The Eternity Rose is put through an intricate three-month process of electroplating, or coating the rose with copper and then with other metals in micro-thin layers. You won’t have to see your flowers sag after a few days because these roses never die. The glitter of gold atop the natural rose (or platinum or silver–whatever you prefer) will fit right in with the Christmas Eve ambiance.
($169 for the gold rose)
Your phone could show if a bridge is about to collapse
In summer 2017, Thomas Matarazzo, then a postdoctoral researcher at the Massachusetts Institute of Technology, landed in San Francisco with a colleague. They rented two cars, drove up to the Golden Gate bridge, timing it to the city’s rush hour, and rode over to the other side in heavy traffic. Once they reached the other end, they turned around and did it again. And again. And again.
“I drove over that bridge 100 times over five days, back and forth,” says Matarazzo, now an associate director of High-Performance Computing in the Center for Innovation in Engineering at the United States Military Academy, West Point. “It was surprisingly stressful, I never anticipated that. I had to maintain the speed of about 30 miles an hour when the speed limit is 45. I felt bad for everybody behind me.”
Matarazzo had to drive slowly because the quality of data they were collecting depended on it. The pair was designing and testing a new smartphone app that could gather data about the bridge’s structural integrity—a low-cost citizen-scientist alternative to the current industrial methods, which aren’t always possible, partly because they’re expensive and complex. In the era of aging infrastructure, when some bridges in the United States and other countries are structurally unsound to the point of collapsing, such an app could inform authorities about the need for urgent repairs, or at least prompt closing the most dangerous structures.
There are 619,588 bridges in the U.S., and some of them are very old. For example, the Benjamin Franklin Bridge connecting Philadelphia to Camden, N.J., is 96-years-old while the Brooklyn Bridge is 153. So it’s hardly surprising that many could use some upgrades. “In the U.S., a lot of them were built in the post-World War II period to accommodate the surge of motorization,” says Carlo Ratti, architect and engineer who directs the Senseable City Lab at Massachusetts Institute of Technology. “They are beginning to reach the end of their life.”
According to the 2022 American Road & Transportation Builders Association’s report, one in three U.S. bridges needs repair or replacement. The Department of Transportation (DOT) National Bridge Inventory (NBI) database reveals concerning numbers. Thirty-six percent of U.S. bridges need repair work and over 78,000 bridges should be replaced. More than 43,500 bridges are rated in poor condition and classified as “structurally deficient” – an alarming description. Yet, people drive over them 167.5 million times a day. The Pittsburgh bridge which collapsed in January this year—only hours before President Biden arrived to discuss the new infrastructure law—was on the “poor” rating list.
Assessing the structural integrity of a bridge is not an easy endeavor. Most of the time, these are visual inspections, Matarazzo explains. Engineers check cracks, rust and other signs of wear and tear. They also check for wildlife—birds which may build nests or even small animals that make homes inside the bridge structures, which can slowly chip at the structure. However, visual inspections may not tell the whole story. A more sophisticated and significantly more expensive inspection requires placing special sensors on the bridge that essentially listen to how the bridge vibrates.
“Some bridges can afford expensive sensors to do the job, but that comes at a very high cost—hundreds of thousands of dollars per bridge per year,” Ratti says.
We may think of bridges as immovable steel and concrete monoliths, but they naturally vibrate, oscillating slightly. That movement can be influenced by the traffic that passes over them, and even by wind. Bridges of different types vibrate differently—some have longer vibrational frequencies and others shorter ones. A good way to visualize this phenomenon is to place a ruler over the edge of a desk and flick it slightly. If the ruler protrudes far off the desk, it will vibrate slowly. But if you shorten the end that hangs off, it will vibrate much faster. It works similarly with bridges, except there are more factors at play, including not only the length, but also the design and the materials used.
The long suspension bridges such as the Golden Gate or Verrazano Narrows, which hang on a series of cables, are more flexible, and their vibration amplitudes are longer. The Golden Gate Bridge can vibrate at 0.106 Hertz, where one Hertz is one oscillation per second. “Think about standing on the bridge for about 10 seconds—that's how long it takes for it to move all the way up and all the way down in one oscillation,” Matarazzo says.
On the contrary, the concrete span bridges that rest on multiple columns like Brooklyn Bridge or Manhattan Bridge, are “stiffer” and have greater vibrational frequencies. A concrete bridge can have a frequency of 10 Hertz, moving 10 times in one second—like that shorter stretch of a ruler.
The special devices that can pick up and record these vibrations over time are called accelerometers. A network of these devices for each bridge can cost $20,000 to $50,000, and more—and require trained personnel to place them. The sensors also must stay on the bridge for some time to establish what’s a healthy vibrational baseline for a given bridge. Maintaining them adds to the cost. “Some bridges can afford expensive sensors to do the job, but that comes at a very high cost—hundreds of thousands of dollars per bridge per year,” Ratti says.
Making sense of the readouts they gather is another challenge, which requires a high level of technical expertise. “You generally need somebody, some type of expert capable of doing the analysis to translate that data into information,” says Matarazzo, which ticks up the price, so doing visual inspections often proves to be a more economical choice for state-level DOTs with tight budgets. “The existing systems work well, but have downsides,” Ratti says. The team thought the old method could use some modernizing.
Smartphones, which are carried by millions of people, contain dozens of sensors, including the accelerometers capable of picking up the bridges’ vibrations. That’s why Matarazzo and his colleague drove over the bridge 100 times—they were trying to pick up enough data. Timing it to rush hour supported that goal because traffic caused more “excitation,” Matarazzo explains. “Excitation is a big word we use when we talk about what drives the vibration,” he says. “When there's a lot of traffic, there's more excitation and more vibration.” They also collaborated with Uber, whose drivers made 72 trips across the bridge to gather data in different cars.
The next step was to clean the data from “noise”—various vibrations that weren’t relevant to the bridge but came from the cars themselves. “It could be jumps in speed, it could be potholes, it could be a bunch of other things," Matarazzo says. But as the team gathered more data, it became easier to tell the bridge vibrational frequencies from all others because the noises generated by cars, traffic and other things tend to “cancel out.”
The team specifically picked the Golden Gate bridge because the civil structural engineering community had studied it extensively over the years and collected a host of vibrational data, using traditional sensors. When the researchers compared their app-collected frequencies with those gathered by 240 accelerometers formerly placed on the Golden Gate, the results were the same—the data from the phones converged with that from the bridge’s sensors. The smartphone-collected data were just as good as those from industry devices.
The study authors estimate that officials could use crowdsourced data to make key improvements that would help new bridges to last about 14 years longer.
The team also tested their method on a different type of bridge—not a suspension one like the Golden Gate, but a concrete span bridge in Ciampino, Italy. There they compared 280 car trips over the bridge to the six sensors that had been placed on the bridge for seven months. The results were slightly less matching, but a larger volume of trips would fix the divergence, the researchers wrote in their study, titled Crowdsourcing bridge dynamic monitoring with smartphone vehicle trips, published last month in Nature Communications Engineering.
Although the smartphones proved effective, the app is not quite ready to be rolled out commercially for people to start using. “It is still a pilot version,” so there’s room for improvement, says Ratti, who co-authored the study. “But on a more optimistic note, it has really low barriers to entry—all you need is smartphones on cars—so that makes the system easy to reach a global audience.” And the study authors estimate that the use of crowdsourced data would result in a new bridge lasting about 14 years longer.
Matarazzo hopes that the app could be eventually accessible for your average citizen scientist to collect the data and supply it to their local transportation authorities. “I hope that this idea can spark a different type of relationship with infrastructure where people think about the data they're collecting as some type of contribution or investment into their communities,” he says. “So that they can help their own department of transportation, their own municipality to support that bridge and keep it maintained better, longer and safer.”
Lina Zeldovich has written about science, medicine and technology for Popular Science, Smithsonian, National Geographic, Scientific American, Reader’s Digest, the New York Times and other major national and international publications. A Columbia J-School alumna, she has won several awards for her stories, including the ASJA Crisis Coverage Award for Covid reporting, and has been a contributing editor at Nautilus Magazine. In 2021, Zeldovich released her first book, The Other Dark Matter, published by the University of Chicago Press, about the science and business of turning waste into wealth and health. You can find her on http://linazeldovich.com/ and @linazeldovich.