Cerruti Marta G, Sauthier Marc, Leonard Donovan, Liu Dage, Duscher Gerard, Feldheim Daniel L, Franzen Stefan
Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA.
Anal Chem. 2006 May 15;78(10):3282-8. doi: 10.1021/ac0600555.
The infrared emissivity of Au and silica-coated Au nanoparticles (Au NPs) deposited on indium tin oxide substrates was investigated. NPs were irradiated with laser light at a frequency close to the Au plasmon resonance band, and the blackbody radiation emitted as a result was monitored with an IR camera equipped with an InAs array detector. The differences in temperature before and after laser irradiation were recorded (T-jumps) and were found to be directly proportional to the number of particles present on the slide and to the laser power used in the experiment. Coating Au NPs with silica increased the measured T-jumps 2-5 times, depending on the thickness of the silica shell. This was in agreement with the observation that silica has a much higher IR emissivity than Au. Both Au and silica-coated Au NPs were then tested as labels for thermographic DNA detection. Target DNA concentrations as low as 100 pM were recorded when Au NPs were used as labels and as low as 10 pM when silica-coated Au NPs were used.
研究了沉积在铟锡氧化物衬底上的金纳米颗粒（Au NPs）和二氧化硅包覆的金纳米颗粒的红外发射率。用频率接近金等离子体共振带的激光照射纳米颗粒，并用配备砷化铟阵列探测器的红外相机监测由此产生的黑体辐射。记录激光照射前后的温度差异（温度跃升），发现其与载玻片上存在的颗粒数量以及实验中使用的激光功率成正比。用二氧化硅包覆金纳米颗粒会使测量到的温度跃升增加2至5倍，这取决于二氧化硅壳层的厚度。这与二氧化硅的红外发射率远高于金的观察结果一致。然后，对金纳米颗粒和二氧化硅包覆的金纳米颗粒作为热成像DNA检测标记物进行了测试。当使用金纳米颗粒作为标记物时，记录到的目标DNA浓度低至100 pM，而当使用二氧化硅包覆的金纳米颗粒时，低至10 pM。
