本發明揭示了一種配體-共軛金奈米顆粒(AuNPs)的合成方法,該方法包含:a)提供一種胺修飾二氧化矽顆粒;b)提供一種含有金離子(Au3+ )的溶液;c)將胺修飾二氧化矽顆粒懸浮於含金離子的溶液中;d)使金離子被吸附在(具有)胺修飾的二氧化矽顆粒表面;e)將吸附有金離子之具有胺修飾的二氧化矽顆粒暴露於輻射下以獲得表面固定有金奈米顆粒(AuNPs)之胺修飾二氧化矽顆粒,其中該AuNPs不具特定表面修飾;且f)將配體加入該表面吸附及/或固定有裸露金奈米顆粒(AuNPs)之胺修飾二氧化矽顆粒,進行取代反應從而獲得配體-共軛之金奈米顆粒(AuNPs)。A method of synthesizing ligand-conjugated gold nanoparticles (AuNPs) is disclosed. The method comprises: a) providing an amine-modified silica particle; b) providing a solution comprising Au+3 ions; c) suspending the amine-modified silica particle in the solution comprising Au+3 ions; d) allowing the Au3+ ions to be adsorbed and/or immobilized onto the surface of the amine-modified silica particle; e) exposing the Au3+ ions immobilized onto the surface of the amine-modified silica particle to radiation to obtain bare gold nanoparticles (AuNPs) adsorbed and/or immobilized onto the surface of the amine-modified silica particle, wherein the bare AuNPs are without surface modifications; and f) reacting a ligand with the bare AuNPs adsorbed and/or immobilized onto the surface of the amine-modified SiNP and thereby obtain ligand-conjugated gold nanoparticles (AuNPs).