based on crosslinked poly(N-isopropylacrylamide) shells undergo a reversible swelling transition upon changing the temperature of the system. This swelling has a considerable influence on the permeability of the shells of these microcontainers, which makes these systems highly attractive for encapsulation and release of biomolecules such as enzymes, proteins, or DNA. (S. K. Fu et al., August 5, Adv. Mater. 2002, 14, 1090-1092)