Prostaglandin E2 (PGE2) is an important biomarker for cancers and chronic inflammation-associated diseases. While PGE2 plays a crucial role in the inflammatory response, chronically elevated PGE2 levels may contribute to disease onset and oxidative stress. Herein, hydroxypropyl β-cyclodextrin (HPbCD)-functionalized MoO 3 quantum dots (QDs) were synthesized with a hydrophilic exterior and hydrophobic core. The QDs were characterized for their physicochemical, bioimaging, and biocompatible nature. The QDs exhibited potential reactive oxygen species (ROS) scavenging and bioimaging in Caenorhabditis elegans. Further, the QD's high binding affinity-based nanomolar detection of PGE2 (2−40 nM) was performed at physiological pH. The detection mechanism was investigated using Stern−Volmer and Lineweaver−Burk equations, where K q (8.9 × 10 15 and 2.85 × 10 14 L/mol/s) and K b 1.1 × 10 7 M −1 with 1:1 binding interaction. The energetically favorable and spontaneous binding of PGE2 to MoCD QDs suggested strong host−guest inclusionbased detection of PGE2. The biosensor performance was tested with a potent interferent and validated in clinical serum samples. The developed biocompatible nanoquantum probe with triad applications, including oxidative stress management, bioimaging, and ultrasensitive detection of PGE2, is envisaged to be a valuable tool in molecular diagnosis in treatment of inflammation.