The present invention relates to a method for inhibiting osteoblast differentiation comprising the step of treating exosomes into which a let-7 inhibitor has been introduced, and it was confirmed that the differentiation ability of osteoblasts was significantly lowered by the method. It is expected that the present invention can be usefully used as a treatment technology for diseases such as calcification of bones or blood vessels, osteosarcoma cancer, etc. caused by uncontrolled disease.본 발명은 let-7 억제제가 도입된 엑소좀을 골모세포에 처리하는 단계를 포함하는 골분화 억제 방법에 관한 것으로, 상기 방법에 의할 경우 골모세포의 분화능이 현저히 떨어지는 것을 확인하였는바, 골분화 조절이 되지 않아 발병되는 뼈 또는 혈관의 석회화, 골육종암 등의 질병의 치료기술로써 본 발명을 유용하게 사용할 수 있을 것으로 기대된다.
