Department of Environmental Health and Engineering , Johns Hopkins University , Baltimore , Maryland 21218-2686 , United States.
Langmuir. 2018 Sep 11;34(36):10774-10781. doi: 10.1021/acs.langmuir.8b01545. Epub 2018 Aug 29.
A facile approach for functionalizing atomic force microscopy (AFM) tips with nanoparticles (NPs) will provide exciting opportunities in the field of tip-enhanced vibrational spectroscopy and in probing the interactions between NPs and biological systems. In this study, through successive exposure to polydopamine and AgNO solutions, the apex of AFM tips was functionalized with silver nanoparticles (AgNPs). The AgNP-modified AFM tips were used to measure the interaction forces between AgNPs and supported lipid bilayers (SLBs) formed on mica, as well as to probe the penetration of SLBs by AgNPs, with an emphasis on the effect of human serum albumin (HSA) proteins. AgNPs experienced predominantly repulsive forces when approaching SLBs. The presence of HSA resulted in an enhancement in the repulsive interactions between AgNPs and SLBs, likely through steric repulsion. Finally, the forces required for AgNPs to penetrate SLBs were higher in the presence of HSA probably due to the increase in the effective size of the nanoscale protuberances on the AFM tip stemming from the formation of protein coronas around the AgNPs.
通过连续暴露于聚多巴胺和 AgNO3 溶液，将原子力显微镜 (AFM) 探针的尖端功能化，得到了银纳米粒子 (AgNPs)。用 AgNP 修饰后的 AFM 探针测量了 AgNPs 与云母上形成的支撑脂质双层 (SLB) 之间的相互作用力，以及 AgNPs 对 SLB 的穿透作用，重点研究了人血清白蛋白 (HSA) 蛋白的影响。AgNPs 在接近 SLB 时主要经历排斥力。HSA 的存在增强了 AgNPs 和 SLB 之间的排斥相互作用，这可能是由于空间排斥。最后，由于 AgNPs 周围形成的蛋白质冠增加了 AFM 探针上纳米级突起的有效尺寸，在 HSA 存在的情况下，AgNPs 穿透 SLB 所需的力更高。
