Nanobiophotonics and Biomedical Research Laboratory, M.I.S. Electronics Inc., Richmond Hill, Ontario L4B 1B4, Canada.
Institute for Advanced Non-Destructive and Non-Invasive Diagnostic Technologies (IANDIT) , University of Toronto, Toronto, Ontario M5S 3G8, Canada.
Biointerphases. 2024 Sep 1;19(5). doi: 10.1116/6.0003715.
In this study, bovine serum albumin (BSA) is used as a globular protein model to examine the conformational changes that occur during the interaction of BSA with N-hydroxysulfo-succinimide (sodium salt)-functionalized gold nanourchins (GNUs), for which dynamic spectroscopic techniques are employed. The results showed that the absorbance of phosphate-buffered saline-BSA at 278 nm decreased when a GNU was added to the solution due to adsorption, and it decreased further when the GNU was increased. The intensity and width of the peak of local surface plasmon resonance increased, indicating the effect of corona formation. Dynamic UV-vis spectroscopy and scattering revealed a nonlinear behavior of BSA-GNU interaction. The bioplasmonic solution resulted in higher transmission and scattering than the BSA solution. Fourier transform-near-infrared spectra exhibited several bands due to overtones and combinations of the amide group and different proportions of α-helix and β-sheet components in BSA before and after the addition of the GNU. Time-resolved fluorescence spectroscopy demonstrated an initial increase in blueshifted emission, followed by a redshifted quenching of two major peaks of Tyr and tryptophan (Trp). The binding and dissociation constants were determined as Kb = 2.17 × 1010 M-1 and Kd = 4.6 × 10-11, respectively, using the Stern-Volmer relation. Both the dynamic CMOS-based imaging and the cadmium sulfide sensors demonstrated a nonlinear response of bioplasmonic solution. By increasing the GNU, the resistance of the solution decreased in the order of A > S1 > S3, where S3 exhibited the highest initial transmission with a longer desorption time. MATLAB modeling showed 80% surface coverage by the protein in 15 s at 0.05M, equivalent to a thickness of 1.7 nm, which was in agreement with the value determined by using the Stokes-Einstein relation.
在这项研究中，牛血清白蛋白（BSA）被用作球状蛋白质模型，以研究在与 N-羟基磺基琥珀酰亚胺（钠盐）功能化的金纳米棒（GNUs）相互作用过程中发生的构象变化，为此采用了动态光谱技术。结果表明，由于吸附作用，当向溶液中添加 GNUs 时，磷酸盐缓冲盐水-BSA 在 278nm 处的吸光度降低，当 GNUs 增加时，吸光度进一步降低。局部表面等离激元共振峰的强度和宽度增加，表明冠状形成的效果。动态紫外可见光谱和散射表明 BSA-GNU 相互作用具有非线性行为。生物等离子体溶液导致比 BSA 溶液更高的透射率和散射率。傅里叶变换近红外光谱显示，由于 BSA 中酰胺基团的泛音和组合以及不同比例的α-螺旋和β-折叠成分的影响，在添加 GNUs 前后，出现了几个谱带。时间分辨荧光光谱表明，两个主要色氨酸（Tyr 和 Trp）峰的发射初始蓝移增加，然后红移猝灭。使用 Stern-Volmer 关系确定结合和解离常数分别为 Kb=2.17×1010M-1和 Kd=4.6×10-11。基于动态 CMOS 的成像和硫化镉传感器均显示出生物等离子体溶液的非线性响应。随着 GNUs 的增加，溶液的电阻按 A>S1>S3 的顺序减小，其中 S3 表现出最高的初始透射率和更长的解吸时间。MATLAB 建模显示，在 0.05M 时，蛋白质在 15s 内达到 80%的表面覆盖率，相当于 1.7nm 的厚度，与使用 Stokes-Einstein 关系确定的值一致。
