Acetaminophen, aka Tylenol, aka America’s favorite over-the-counter placebo with a liver warning, is widely used. Make that overused, in my opinion [1]. It’s taken by nearly everyone, including breastfeeding women. So naturally, infants end up sipping it secondhand via breast milk. Is this a problem? Maybe.
Despite its reputation as a "safe" drug, acetaminophen (APAP) has been implicated in the development of childhood asthma and allergies. It's also under scrutiny as a potential problem in neurodevelopmental disorders. It is also one of the leading causes of poisoning in children. Women are being "extra careful" to avoid drugs that could be passed on to their infants, but often lack the knowledge of which medications are or are not safe during breastfeeding. And there is no easy way to measure any medications in breast milk. This may change.
A group from the University of Southern California (USC) recently published a study in the journal Device that for the first time could provide a quick, non-invasive, and inexpensive way to measure acetaminophen (and other drugs) in breast milk using a "high-tech bra." It's quite clever.
(Left) Breast milk monitoring device. (Right) The sensor uses a graphene electrode to detect acetaminophen through electrochemical oxidation. As acetaminophen is converted to N-acetyl-p-benzoquinone imine (NAPQI), it loses electrons, generating a current. The strength of that current reveals how much drug is present in the breast milk. Photos: Mousavi, et. al., Device
The USC group's high-tech lactation pad – basically a breast milk version of a roadside DUI breathalyzer is wearable, disposable, and uses real chemistry to tell mothers if their milk is "laced" with Tylenol. The device is also applicable to other drugs.
How it works (good luck with this)
Here’s how it works: the pad contains a laser-induced graphene (LIG) sensor and microfluidic paper channels that slurp up leaked milk and analyze it electrochemically. Specifically, it uses square wave voltammetry (don't think for a second that you will understand this) to measure the oxidation peak of acetaminophen. (Translation, such as it is: it detects acetaminophen based on how easily it gives up electrons.)
The sensitivity is high, detecting APAP in the range of 10 to 600 micromolar. (This covers the pharmacologically relevant window.) It works with milk from 1, 6, or 12 months postpartum [2], and is not affected by the presence of other common drugs, e.g., amoxicillin. No lab, no centrifuge, no pipette—just a pad inside a bra with some sophisticated chemistry thrown in. There are two modes: a “one-and-done” test for checking before a feeding, and a continuous monitoring mode for the rest of the day.
The graphene electrodes were engineered for conductivity and flexibility, and the device is resilient to bending and shelf time, at least 50 days. Its recovery rate (how much acetaminophen the sensor can detect, compared to how much is really there) is above 95%. Cost? A whole lot less than HPLC-MS and a babysitter.
But the real story isn’t just the gadget; it’s the precedent. This is the first-ever on-body sensor for real-time drug monitoring in breast milk. It turns a passive process into a controlled one, and it opens the door to detecting other drugs, hormones, or metabolic markers the same way.
Is it available to concerned mothers? Nope. It’s still in development. The USC team used breast milk for testing, but the “super bra” hasn’t yet been worn by actual moms. So, it’s unlikely to show up in a Victoria’s Secret catalog anytime soon.
NOTES:
[1] Some of my articles questioning the use of APAP can be found here, here, and here.
[2] The timing of measurement matters because the composition of breast milk, especially its protein and fat content, changes over the course of lactation.
Josh Bloom
Director of Chemical and Pharmaceutical Science
Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. He holds a Ph.D. in chemistry.
