本發明係關於功能化量子點，量子點複合物(QD conjugate)包括量子點及一個與量子點結合的配位體，該配位體至少應含一硫醇分子和一其他官能基。量子點複合物亦包含一生物活性劑與配位體共價結合，形成一個被生物活性劑標記之量子點複合物。量子點複合物之製備步驟包含：(1)提供一內含量子點的樹狀聚合物之溶液；(2)在該溶液中加入配位體；(3)配位體和含量子點之樹狀聚合物進行表面分子置換，以取得配位體-量子點化合物，該配位體共價結合於量子點表面。合成方法亦包括配位體-量子點化合物與生物活性劑之結合，以獲取被生物活性劑標記之配位體-量子點化合物。 A quantum dot (QD) conjugate comprises a QD and a ligand conjugated with the QD, in which the ligand has at least one thiol and at least one other functional group. The QD conjugate may further comprise a bioactive agent covalently coupled to the ligand to form a bioactive agent-tagged QD conjugate. A method for preparing a QD conjugate comprises the steps of: (1) providing a solution comprising a QD encapsulated within a dendrimer; (2) adding into the solution a ligand; and (3) allowing an exchange between the ligand and the dendrimer for the QD to obtain a ligand-QD conjugate, in which the ligand is covalently conjugated to the surface of the QD. The method may further comprise the step of coupling the ligand-QD conjugate to a bioactive agent to obtain a bioactive agent-tagged ligand-QD conjugate.