Carboxy-terminated oligomers of N,N-diethylacrylamide (DEAAm) of low polydispersity were synthesized by group-transfer polymerization. The oligomers were conjugated with polylysine. The resulting conjugates possessed lower critical solution temperatures (LCST) around 29 degrees C. Non-stoichiometric conjugate-DNA complexes reversibly precipitated above the conjugate's LCST.