Electrochemical Devices for Accessible Analysis of Human Milk

Human milk is a uniquely tailored source of nutrition that offers a multitude of benefits for both the infant and the mother. Rich in antibodies, enzymes, and essential nutrients, human milk supports the infant's immune system, promotes optimal growth and brain development, and reduces the risk of infections, allergies, and chronic conditions such as obesity and diabetes. For the mother, breastfeeding facilitates uterine contraction, aiding postpartum recovery, and is associated with a reduced risk of breast and ovarian cancers, type 2 diabetes, and cardiovascular disease. Moreover, breastfeeding fosters a strong emotional bond between mother and child, promoting psychological well-being and long-term attachment. The dynamic composition of human milk, which adapts to the changing needs of the growing infant, highlights its irreplaceable role in early-life health and development. Accessible analysis in breast milk can support breastfeeding and enhance the benefits of milk for infants. Analysis of biomarkers such as vitamins, sugars, minerals can assist the mother in adjusting diet to meet the infant needs. Analysis of medications in milk can help with lactating individual perform informed pump and dump to minimize the exposure of infant to medication. Despite widespread advancement of wearable devices and point-of-care sensors, very few tools have been developed for accessible analysis of human milk. The only accessible tool is a colorimetric alcohol test strip. In our work, we have developed a range of electrochemical sensors for analysis of various biomarkers in human milk. Our electrochemical sensors are developed using direct laser engraving on a polyimide film and carbonizing the material to form conductive graphitic carbon (referred to as LIG or laser-induced graphene). The LIG electrodes are compact and flexible and can be produced at scale without the need for lithography or printing methods. We have developed methods for changing surface properties of LIGs to tune capacitance and wettability to engineer the surface for different sensing designs. A wide range of sensors are developed in our work through modification of LIG surface with enzymes, nanoparticles, and ion sensing membrane. 1,2 Extensive characterization of sensors is performed in milk collected from different lactation stages (1 month, 6 month, and 12 month postpartum). To enhance the adoption for a busy parent, our sensors are integrated or coupled with a lactation pad. We present a novel approach to monitoring breast milk by embedding advanced sensing technology directly into a lactation pad, transforming it into a smart, wearable platform for real-time, on-body analysis. Lactation pads are commonly used by breastfeeding individuals to manage milk leakage and maintain comfort throughout the day. By incorporating microfluidic systems and electrochemical sensors into this familiar item, our design enables passive, continuous collection and monitoring of breast milk biomarkers without disrupting the user's daily routine. This seamless integration eliminates the need for separate sampling procedures, offering an effortless and non-invasive method for frequent health assessment of both mother and infant. Mom and Baby Wellness with a Smart Lactation Pad: A Wearable Sensor-Embedded Lactation Pad for on-Body Quantification of Glucose in Breast Milk, Advanced Functional Materials, 2025, 2420973. https://doi.org/10.1002/adfm.202420973. Safer breastfeeding with a wearable sensor for monitoring maternal acetaminophen transfer through breast milk, Device (Cell Press), 2025, accepted. Figure 1