Chen Yi-Ming, Yu Cheng-Ju, Cheng Tian-Lu, Tseng Wei-Lung
Department of Chemistry, National Sun Yat-sen University, Taiwan.
Langmuir. 2008 Apr 1;24(7):3654-60. doi: 10.1021/la7034642. Epub 2008 Feb 16.
In this study, an aqueous solution of 13-nm gold nanoparticles (AuNPs) covalently bonded with human serum albumin (HSA) was used for sensing lysozyme (Lys). HSA molecules were good stabilizing agents for AuNPs in high-salt solution and exhibited the ability to bond with Lys electrostatically. The aggregation of HSA-AuNPs was achieved upon the addition of high-pI proteins, such as Lys, alpha-chymotrypsinogen A, and conalbumin. Not the same was achieved, however, when low-pI proteins such as ovalbumin, bovine serum albumin, and alpha-lactalbumin were added. Matrix-assisted desorption/ionization mass spectrometry was used to demonstrate the interaction between HSA-AuNPs and Lys. It was found that the sensitivity of HSA-AuNPs for Lys was highly dependent on the HSA concentration. The Lys-induced aggregation of HSA-AuNPs was suggested based on the London-van der Waals attractive force. We further improved the selectivity of the probe by adjusting the pH solution to 8.0. Under the optimum conditions, the selectivity of this system for Lys over other proteins in high-salt solutions was remarkably high, even when their pI was very close to the Lys. The lowest detectable concentration of Lys in this approach was 50 nM. The applicability of the method was validated through the analyses of Lys in chicken egg white.
在本研究中，将与人血清白蛋白（HSA）共价结合的13纳米金纳米颗粒（AuNPs）水溶液用于检测溶菌酶（Lys）。HSA分子在高盐溶液中是AuNPs的良好稳定剂，并表现出与Lys静电结合的能力。加入高pI蛋白（如Lys、α-胰凝乳蛋白酶原A和伴清蛋白）后，HSA-AuNPs发生聚集。然而，加入低pI蛋白（如卵清蛋白、牛血清白蛋白和α-乳白蛋白）时则不会发生这种情况。采用基质辅助激光解吸/电离质谱法来证明HSA-AuNPs与Lys之间的相互作用。发现HSA-AuNPs对Lys的灵敏度高度依赖于HSA浓度。基于伦敦-范德华吸引力，推测Lys诱导了HSA-AuNPs的聚集。我们通过将溶液pH值调节至8.0进一步提高了探针的选择性。在最佳条件下，即使在高盐溶液中其他蛋白质的pI与Lys非常接近时，该系统对Lys相对于其他蛋白质的选择性也非常高。该方法检测Lys的最低可检测浓度为50 nM。通过对鸡蛋白中Lys的分析验证了该方法的适用性。
