St. Petersburg State University, 199034 Saint-Petersburg, Russia; Kazan Federal University, 420008 Kazan, Russia.
St. Petersburg State University, 199034 Saint-Petersburg, Russia.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Oct 15;279:121467. doi: 10.1016/j.saa.2022.121467. Epub 2022 Jun 6.
Metal nanoclusters (NCs) are widely present today in biosensing, bioimaging, and diagnostics due to their small size, great biocompatibility, and sensitivity to the biomolecular environment. Silver (Ag) NCs often possess intense fluorescence, photostability, and low photobleaching, which is in high demand during the detection of organic molecules. Pterins are small compounds, which are used in medicine as biomarkers of oxidative stress, cardiovascular diseases, neurotransmitter synthesis, inflammation and immune system activation. It is experimentally possible to detect pterin (Ptr) through the adsorption on Ag colloid. We optimized geometries and evaluated the binding energy in Ptr-Ag complexes (n = 1-6; q = 0, +1, +2) using quantum chemistry methods. Different Ptr atoms were preferential for silver attachment depending on NC charge and size. The highest E was obtained for the complexes between the Ptr and Ag (-50.8 kcal mol), between Ptr and Ag (-64.8 kcal mol), which means that these complexes should be formed preferably in aqueous solutions in acidic and alkaline media, respectively. The colorimetric detection of pterin with silver clusters does not seem to be promising. However, intense SS transitions of Ag complexes look promising for luminescent Ptr detection. SERS detection of pterin is better to be done at pH > 8 since deprotonated pterin Raman undergo more dramatic changes upon addition of Ag than the neutral pterin. The characteristics of absorption and vibrational spectra of silver-pterin should be exploited during biosensor development.
金属纳米团簇（NCs）由于其尺寸小、生物相容性好、对生物分子环境敏感，目前广泛应用于生物传感、生物成像和诊断领域。银（Ag）NCs 通常具有强烈的荧光、光稳定性和低光漂白性，这在检测有机分子时非常需要。蝶呤是一种小分子化合物，在医学中用作氧化应激、心血管疾病、神经递质合成、炎症和免疫系统激活的生物标志物。通过吸附在 Ag 胶体上，实验上可以检测蝶呤（Ptr）。我们使用量子化学方法优化了 Ptr-Ag 配合物（n=1-6；q=0，+1，+2）的几何形状并评估了结合能。不同的 Ptr 原子根据 NC 的电荷和大小优先与银结合。在 Ptr 和 Ag 之间（-50.8 kcal/mol）和 Ptr 和 Ag 之间（-64.8 kcal/mol）获得的最高 E 表明，这些配合物应该分别在酸性和碱性介质中的水溶液中优先形成。用银团簇进行蝶呤的比色检测似乎不太有希望。然而，Ag 配合物的强烈 SS 跃迁对于发光 Ptr 检测看起来很有希望。SERS 检测蝶呤最好在 pH > 8 下进行，因为与中性蝶呤相比，加入 Ag 后去质子化的蝶呤 Raman 会发生更剧烈的变化。在生物传感器的开发过程中，应该利用银-蝶呤的吸收和振动光谱特性。
