Jan Eijkel and Albert van den Berg from the MESA+ Research Institute, Twente, co-ordinate a regular series of mini-reviews that are tightly focused on recent research. These articles cover trends in recent research, focus on potential new areas of research or even potential applications. Aiming to inform the reader about such recent trends, bring forgotten papers back into the spotlight and perhaps most importantly, to provide a perspective of a particular subject as well as a critical evaluation of it that may help researchers to plan future research. Six mini-reviews will be published each year.