(1) Skin-Interfaced Bioelectronics & Biosensors. Chronic kidney disease (CKD) is a condition where kidneys are damaged and cannot filter blood as well as healthy ones. 30 million or 15% of US adults are estimated to have CKD but most of them are not aware of it at an early stage of the disease. Early detection and treatment can often keep chronic kidney diseases from getting worse. Therefore, a novel method for painless and stress-free kidney health monitoring is highly desirable. I developed a wearable sweat sensor that can capture and analyze creatinine and urea in sweat for the early detection of CKD.
(2) Brain-Interfaced Microsystem. Diseases related to the central and peripheral nervous systems, such as depression, anxiety, addiction, pain, Alzheimer’s, and amyotrophic lateral sclerosis, affect the life quality of millions of people worldwide. To understand the function of neural networks and the causes of these mental health problems, I designed and fabricated injectable/implantable optofluidic devices for brain and peripheral nerve interfaces. This technology has been transferred from the research bench to commercialization by a startup company Neurolux (http://neurolux.org/).
(3) Soft Materials-Complex Colloidal Systems. My major accomplishment is the discovery of a new class of soft materials called capillary foams. I studied its stabilization mechanism, the effect of system parameters, and its potential applications in energy-efficient separations. This research has been reported by many press releases, such as Science Daily, NSF News, and World Industrial Reporter. My second contribution is that I answered a question that exists in the colloid community for a few decades. Over one hundred years ago, people found that colloidal particles with suitable wettability can adsorb to (and stabilize) the fluid-fluid interfaces. However, there is a long ongoing debate about whether the adsorption of non-amphiphilic particles in the interface can change the interfacial tension. I answered this question by conducting systematic experimental and theoretical studies. My studies show that particles do reduce the interfacial tension, which depends on the packing density and contact angle of particles in the interface. This insight is important for understanding and controlling the assembly of non-amphiphilic nanoparticles at fluid–fluid interfaces, which is crucial for applications from food technology to oil recovery.