纳米金是指粒径介于1~100 nm 之间的金粒子，具有良好的生物兼容性、结构稳定性和光学性质，可用于强化激光治疗血管性皮肤病的光吸收。采用柠檬酸钠还原法制备纳米金胶体，研究了温度、加热时间、柠檬酸钠还原剂用量等因素对其粒径和吸收光谱的影响，得到了制备纳米金胶体的最佳条件。取制备得到的粒径为16 nm 左右的纳米金胶体与血液混合后稀释，研究了胶体金对血液光吸收性能的影响及其随温度的变化规律。结果表明，加入胶体金后血液的光吸收性能随着加入体积比的增大而增强，当胶体金与血液的体积比为5时，血液在545 nm 和581 nm处的吸收峰值分别提高了1.33倍和1.09倍。在变温条件下，胶体金不会对血液的动态吸收特性产生影响。

Nano gold refers to the particles with size between 1~100 nm, it can be used to strengthen the light absorption of blood in the process of laser treatment of vascular dermatosis because of its good biological compatibility, structural stability and optical properties. The gold colloid is prepared with sodium citrate as reducing agent. Effect of temperature, reaction time, sodium citrate dose on the size and absorption spectra of gold colloid is studied. Thus the best condition for preparing gold colloid is obtained. After the gold colloid with size of 16 nm is prepared, it is added to blood to study the effect of colloidal gold on the properties of light absorption of blood as a function of temperature. The results show that the absorption of blood increases with the increase of volume ratio. Blood absorption peak values at 545 nm and 581 nm increase by 1.33 times and 1.09 times respectively when the ratio is 5. Under the condition of variable temperatures, colloidal gold does not affect the dynamic absorption characteristics of blood.