Santanu Patra is research scientist at the Technical University of Denmark, Kongens Lyngby, Denmark. He works in the field of materials chemistry, specializing in the integration of functional materials with macro-, micro-, and nano systems. His current research focuses on multifaceted nanotechnological approaches for novel sensing and energy harvesting technologies for healthcare applications.Mika Sillanpää is a professor at the University of Johannesburg, South Africa. His research centers on chemical treatment in environmental engineering, environmental monitoring, and resource recovery from waste streams.Sillanpää received his M.Sc. (Eng.) and D.Sc. (Eng.) degrees from the Aalto University where he also completed an MBA degree in 2013. Since 2000, he has been a full professor/adjunct professor at the University of Oulu, the University of Eastern Finland, the LUT University, the University of Eastern Finland and the University of Johannesburg.