Physicochemical Properties, Biomolecular Corona, Bioactivity, and Pharmacology-Based Issues of Biopolymers: A Brief Overview: Letter in Response to an Opinion Article Published in Trends in Biotechnology: Wang, C. and Dong, L. (2015) Exploring 'New' Bioactivities of Polymers at the Nano–Bio Interface. Trends Biotechnol. 33, 10–14. Issue 2 (February 2016)