A construct for selectively delivering a compound of interest to a cell, includes (a) a bioresorbable polymer shell (b) a nucleic acid duplex contained in said shell, the duplex comprising (i) an ATP binding nucleic acid, and (ii) a complementary nucleic acid hybridized to the ATP binding nucleic acid (c) a compound of interest intercalated in or caged by the nucleic acid duplex (d) optionally, but in some embodiments preferably, a cationic polymer in said polysaccharide shell and (e) optionally, but in some embodiments preferably, a cell targeting ligand coupled to the polymer shell. The polymer shell is degraded in a cell of interest, or in the extracellular matrix of a tissue carrying said cell of interest, to release said duplex therein. The wherein said duplex is destabilized by binding of ATP in the cell of interest to release the compound of interest therein.