TTK21 is an activator of CBP/p300 histone acetyltransferase activity. It activates CBP/p300 histone acetyltransferase activity in a concentration-dependent manner with a maximal effect at a concentration of 275 µM, inducing acetylation of histones H3 and H4 in vitro but not H2B and H2A. TTK21, conjugated to glucose-based carbon nanospheres (CSP), crosses the blood-brain barrier and increases histone acetylation of H2B and H3 as well as H4K12 in mouse frontal cortex and H2B and H3 in the dorsal hippocampus and brainstem. CSP-TTK21 (20 mg/kg) also induces differentiation and maturation of neuronal progenitors in the subgranular zone of the dentate gyrus in adult mice and increases memory duration in the Morris water maze with mice spending more time in the platform quadrant compared with untreated mice up to 16 days after learning.