Terrified of bloodwork, needles, and clinic bills? Science is getting closer and closer to collecting our health data in fast, affordable, and pain-free ways – the latest example being a cup sticker that measures vitamin C levels in the user's sweat.
There have been many previous attempts to create sweat sensors that can analyze various health metrics, such as stress levels, hydration – and yes, even vitamin C levels. What they all have in common is that they stick to the skin, so they're not that easy to forget about.
But an engineering team from the University of California San Diego is redefining what health trackers can look like. They’ve developed the Smart Cup platform, and it’s pretty much an entire lab built into a small sticker that goes on the outside of any cup instead of on your skin. It’s battery-free, wireless, compact, and really cheap.
Malnutrition and vitamin deficiencies affect millions of people worldwide. And it makes sense: understanding your body and adjusting your diet is not possible without regular health monitoring. But that requires planning, time, and often can be very expensive – depending on where you live. This is why a lot of people skip their checkups for years, which results in significant health issues in the long run.
Take vitamin C, for example. Knowing your level matters, as deficiency can lead to anemia, gum bleeding, slow wound healing, and other unpleasant conditions. Measuring it traditionally requires saliva or blood samples, along with expensive lab equipment. And what makes tracking even harder is that vitamin C levels fluctuate quite frequently, so there is no efficient, affordable way to monitor those changes in real time. Well, there wasn’t until now.
“We’re moving toward a future of 'unawareables' – devices that are unobtrusive and essentially invisible so that you are unaware that you’re even using them,” explained study co-senior author Patrick Mercier, a professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering. “Most people only get a snapshot of their health once a year at the doctor. But our bodies change much more frequently than that. We want to make access to health data as frequent and effortless as holding your morning coffee cup or orange juice bottle.”
The Smart Cup sticker is a flexible patch that can monitor your vitamin C level using only sweat from your fingertips. Despite having a small surface area, fingertips can produce hundreds of times more sweat than other parts of the body, and it doesn’t take any effort from the user.
During testing, the stickers were placed onto plastic glasses filled with orange juice, and they accurately measured the increase in participants’ vitamin C levels after they drank the juice.
The sticker is built on a flexible polymer sheet and consists of a porous hydrogel pad to collect sweat, along with a biofuel cell that converts chemicals in the sweat into electricity, which powers a printed circuit board and the vitamin C sensor. The circuit board reads signals from this sensor and transmits data via Bluetooth.
It only takes a few minutes for the device to collect enough sweat, analyze it, and wirelessly send the results to a nearby computer. The stickers can power themselves from sweat-produced energy for over two hours, making them essentially single-use, but they are also easily disposable.
Because the stickers have no battery or any expensive components, they can be made very small and manufactured for just a few cents per unit. Compared to US$50 for a single vitamin C blood test in the United States, this technology could become a solution for low-income regions and improve access to such tests.
And vitamin C is just the beginning. The research team is working on measuring more nutrients and biochemicals in the future, as well as allowing the device to send data directly to smartphones, making real-time health tracking even easier.
A paper on the research was recently published in the journal Biosensors and Bioelectronics.
Source: UC San Diego
