Colorimetric platform using the aggregation of gold nanoparticles (AuNPs) is a pretty simple method for biosensing, but advanced instruments such as specterophotometer is still needed to achieve accurately quantitative readout. Aggregated AuNPs exhibit excellent photothermal properties under near-infrared laser irradiation, which is significantly different from non-aggregated AuNPs. Herein, given the different photothermal effect, we translated the AuNPs-based colorimetric assay into a photothermal assay for the quantitative detection of adenosine using a thermometer as readout. Short single-stranded DNA (ssDNA, adenosine aptamer) was adsorbed on the surface of AuNPs and hence prevented the aggregation of AuNPs under high ionic concentration. The presence of adenosine caused the structural change of ssDNA and the AuNPs became aggregated. The enhanced temperature under NIR-laser irradiation has a linear response to the concentration of adenosine in the range of 2.0-50.0 μM. The detection limit was 1.7 μM. This proposed method is portable, easy and applicable to the quantitative assay of other targets by simply replacing of the sequence of ssDNA.

中文翻译：

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目标触发的金纳米颗粒聚集，用于使用温度计作为读数的腺苷光热定量检测

使用金纳米粒子 (AuNPs) 聚集的比色平台是一种非常简单的生物传感方法，但仍需要分光光度计等先进仪器来实现准确的定量读数。聚集的AuNPs在近红外激光照射下表现出优异的光热性能，这与非聚集的AuNPs有显着差异。在此，考虑到不同的光热效应，我们将基于 AuNPs 的比色测定转化为光热测定，用于使用温度计作为读数对腺苷进行定量检测。短单链 DNA（ssDNA、腺苷适体）吸附在 AuNPs 表面，从而防止 AuNPs 在高离子浓度下聚集。腺苷的存在导致 ssDNA 的结构变化，并且 AuNPs 变得聚集。NIR 激光照射下的温度升高对腺苷浓度在 2.0-50.0 μM 范围内具有线性响应。检测限为1.7 μM。这种提出的方​​法是便携式的、简单的并且适用于通过简单地替换 ssDNA 序列来对其他目标进行定量分析。