A membrane with nanoscale pores allows controlled sweat stimulant release

When people sweat, they unknowingly release a wide range of chemicals that can noninvasively inform clinicians on anything from stress hormone levels to glucose. But it's hard for researchers to glean this information--unless you sweat a lot. Emerging wearable devices using stimulant gels have provided a way to induce sweat locally on the body. However, sweat can dilute these gels, which degrades their long-term viability.