Rational optimization of nanoparticle (NP) surfaces is essential for successful conjugation of proteins to NPs for numerous applications. Using surface-roughened NPs (SRNPs) and quasi-spherical NPs (QSNPs) as two model nanostructures, we examined the effects of local surface curvature on protein conformation and interfacial behaviors by circular dichroism (CD) spectroscopy, fluorescence emission spectroscopy (FES), and isothermal titration calorimetry (ITC). The surface of SRNPs consisted of a mixture of undercoordinated and close-packed surface atoms at the highly curved and locally flat surface regions, respectively, whereas QSNPs were primarily enclosed by {100} and {111} facets covered with close-packed surface atoms. Our findings demonstrated that: 1) SRNPs possess higher tendency to denature BSA and accommodate a higher number of BSA molecules on the surface and 2) the aggregation of AuNP-BSA complexes, likely induced by either denatured BSA or reduced electrostatic repulsion between complexes, is dependent on both the BSA concentration and the NP surface curvature. This study also indicated that NP local surface curvature could potentially be used as a design strategy to preserve the biological function of proteins.

中文翻译：

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纳米级表面曲率调节纳米粒子-蛋白质相互作用。

纳米粒子（NP）表面的合理优化对于蛋白质与NP的成功缀合对于许多应用而言至关重要。使用表面粗糙化的NPs（SRNPs）和准球形NPs（QSNPs）作为两个模型纳米结构，我们通过圆二色性（CD）光谱，荧光发射光谱（FES）检查了局部表面曲率对蛋白质构象和界面行为的影响，和等温滴定热法（ITC）。SRNPs的表面分别由在高度弯曲和局部平坦的表面区域的配位不足和紧密堆积的表面原子组成，而QSNPs主要被{100}和{111}面所包围，这些小面被紧密堆积的表面原子覆盖。我们的发现表明：1）SRNP具有更高的使BSA变性的趋势，并在表面上容纳更多的BSA分子; 2）AuNP-BSA复合物的聚集可能是由变性的BSA或复合物之间静电排斥力降低引起的，均取决于BSA浓度和NP表面曲率。这项研究还表明，NP局部表面曲率可能被用作保留蛋白质生物学功能的设计策略。