The purpose of this talk is twofold. First, to highlight the significant contributions of the late Professor Rudolf Podgornik in five research areas: physics of DNA, virus capsids, Casimir effect, fluctuation-induced interactions, and the role of electric charge in soft matter systems. Second, to introduce two projects related to charged soft matter. (i) The surface tension of electrolytes has a history spanning a century, beginning with Onsager's groundbreaking work. This topic will be examined again using a field-theoretical approach that incorporates ionic specificity based on the Hofmeister series. (ii) The idea of charge regulation provides a more realistic way to understand biomolecules with charges that can dissociate into the surrounding water. Recent modeling of charge regulation will be presented, along with its applications to proteins, polyelectrolytes, and membranes.