State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China.
Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Science, Jilin University, Changchun 130012, P. R. China.
Anal Chem. 2020 Nov 3;92(21):14325-14329. doi: 10.1021/acs.analchem.0c03165. Epub 2020 Oct 21.
The use of silver nanoparticles (Ag NPs) as substrates to obtain satisfactory Raman spectra of native proteins is a simple and valuable but challenging process. Herein, the Ag NPs modified with aluminum and iodide ions (Ag IANPs) were introduced for Raman detection of proteins, including acidic BSA (PI 4.7), catalase (PI 5.4), β-casein (PI 4.5), α-casein (PI 4.0), insulin (PI 5.35), basic myoglobin (PI 6.99), and lysozyme (PI 11.2). The Raman signals of all the detected proteins were significantly improved in comparison with the reported spectra obtained by using Ag NPs containing NaSO, I, and Mg. Specifically, detection sensitivities of the acidic proteins were drastically increased. The limit of detection (LOD) of bovine serum albumin (BSA), α-casein, and β-casein was 0.03 ng/mL. The LOD of insulin and catalase were 0.3 and 3 ng/mL, respectively. As the bands corresponding to disulfide bonds, α-helices, residues of Phe, Trp, and Tyr, and carboxyl groups were also greatly enhanced, it was easy to monitor the folding of native protein and the denaturation of protein under acidic and heated conditions. Thus, Ag IANPs as substrates open a way for surface-enhanced Raman spectroscopy (SERS) detection of proteins. Hence, the method can provide more valuable information about protein and, therefore, has the potential for wide applications.
使用银纳米粒子（Ag NPs）作为基底来获得天然蛋白质令人满意的拉曼光谱是一种简单而有价值但具有挑战性的方法。在此，引入了经过铝和碘离子修饰的 Ag NPs（Ag IANPs），用于蛋白质的拉曼检测，包括酸性牛血清白蛋白（PI 4.7）、过氧化氢酶（PI 5.4）、β-酪蛋白（PI 4.5）、α-酪蛋白（PI 4.0）、胰岛素（PI 5.35）、碱性肌红蛋白（PI 6.99）和溶菌酶（PI 11.2）。与使用含有 NaSO、I 和 Mg 的 Ag NPs 获得的报道光谱相比，所有检测到的蛋白质的拉曼信号都得到了显著增强。具体而言，酸性蛋白质的检测灵敏度大大提高。牛血清白蛋白（BSA）、α-酪蛋白和β-酪蛋白的检测限（LOD）分别为 0.03ng/mL、0.03ng/mL 和 0.03ng/mL。胰岛素和过氧化氢酶的 LOD 分别为 0.3ng/mL 和 3ng/mL。由于二硫键、α-螺旋、Phe、Trp 和 Tyr 残基以及羧基的对应峰也得到了极大的增强，因此可以很容易地监测天然蛋白质的折叠以及在酸性和加热条件下蛋白质的变性。因此，Ag IANPs 作为基底为表面增强拉曼光谱（SERS）检测蛋白质开辟了一条道路。因此，该方法可以提供有关蛋白质的更有价值的信息，因此具有广泛的应用潜力。
