||Metal-organic frameworks (MOFs) are porous hybrid materials constructed by metal nodes and bridging organic linkers. The MOFs with their exceptionally high surface area are potential candidates in various fields of application such as drug delivery system. Herein, we developed means to functionalize the surface of MOF particles with poly(acrylic acid) (PAA) and load an anticancer, 5-fluorouracil (5-Fu), into the frameworks in one spot. We envision that carboxylic group from PAA may enhance the growth of biominerals such as calcium phosphate (CaP). A pH-responsive release of 5-Fu could be realized by the encapsulating CaP, which is easily decomposed near acidic cancer system. We are in the process of optimizing the conditions to control the encapsulation of the MOF in CaP. Structural and spectroscopic studies of MOF particles, their functionalized, drug-loaded and CaP-encapsulated forms as well as the comparisons of in vitro release depending on pH of the solution will be discussed.