초록 |
Molecular design concepts are described for the preparation of azobenzene polymers capable of showing a tunable response to the rat liver microsome-induced side-chain self-immolation process under hypoxic conditions. It is shown that azobenzene nuclei carrying a donor/acceptor substitution pattern are the most active system towards the enzymatically triggered azobenzene cleavage reaction (half-life = t1/2 = 6 min). Their activity is followed by azobenzene nuclei carrying donor/donor (t1/2 = 20 min), electronically non-substituted (t1/2 = 72 min), and acceptor (t1/2 = 78 min) systems. This trend is preserved when a chemical stimulus, sodium dithionite, replaces the biological reducing conditions and demonstrates generality of the findings, and their potential in proteomics procedures. This work, therefore, establishes general principles for the molecular design of biologically activatable and cleavable azobenzene-based polymeric scaffolds applicable to delivery and imaging applications. |