Interactions at the Silica-Peptide Interface: The Influence of Particle Size and Surface Functionality
Interactions at the Silica-Peptide Interface: The Influence of Particle Size and Surface Functionality
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DOI：
10.1021/la403242f
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发表时间：
2014-01-14
期刊：
影响因子：
3.9
通讯作者：
Perry, Carole C.
中科院分区：
文献类型：
--
作者：
Puddu, Valeria;Perry, Carole C.
在二氧化硅/水界面处可能发生的各种相互作用使得二氧化硅纳米颗粒（SiNP）成为技术应用的有吸引力的材料。尽管它们的重要性，界面相互作用没有得到充分的理解。在这篇文章中，我们研究了（1）粒径和（2）表面功能化对SiNP上小生物分子粘合剂吸附的影响。使用具有不同性质（电荷、pI和氨基酸组成）的小二氧化硅结合肽作为粘合剂，而一系列直径在28和500 nm之间的完全表征的SiNP（原始二氧化硅）和约100 nm的SiNP（未处理二氧化硅）被用作粘合剂。用阳离子3-氨基丙基和疏水甲基官能化的500 nm用作结合底物。吸附和结合亲和力进行了研究，在pH 7.4的荧光测定。颗粒的表面化学的详细表征表明，改性二氧化硅上的表面官能化程度远低于单层覆盖率[通过X射线光电子能谱（XPS），约100%]。2和18原子%的氨基和甲基改性的表面分别]。虽然肽结合通常由吸附肽的物理化学特性调节，但将这种小程度的功能性引入二氧化硅颗粒上足以在二氧化硅/水界面处产生吸附的剧烈变化。此外，观察到肽吸附随粒径增加而增加，与肽的性质和性质无关。这种颗粒尺寸效应归因于较大SiNP上的主要结合机制向静电相互作用的转变。所呈现的数据表明，粒径和表面官能度都是可以通过在二氧化硅/肽界面处的特异性结合模式的调节或选择而实质上影响（生物）分子摄取的参数。这些结果是适用于设计和开发的接口与特定的吸附/亲和反应的生物医学应用，其中摄取是重要的，如药物输送。此外，它们提供了关于如何通过靶标表面的表面化学的微小变化来确定生物淘选期间的肽亲和力和选择的重要见解，在某些情况下，这些变化可能与杂质的存在有关。
The variety of interactions that can occur at the silica/aqueous interface makes silica nanoparticles (SiNPs) attractive materials for technological applications. Despite their importance, interfacial interactions are not fully understood. In this contribution, we investigate the effect of (1) particle size and (2) surface functionalization on the adsorption of small biomolecular binders on SiNPs. Small silica binding peptides with different properties (charge, pI, and amino acid composition) were used as binders, while a range of fully characterized SiNPs of diameters ranging between 28 and 500 nm (pristine silica) and SiNPs of ca. 500 nm functionalized with cationic 3-aminopropyl groups and hydrophobic methyl groups was used as binding substrates. Adsorption and binding affinity were investigated by a fluorimetric assay at pH 7.4. A detailed characterization of the surface chemistry of the particles showed that the extent of surface functionalization on modified silica was well below monolayer coverage [by X-ray photoelectron spectroscopy (XPS), ca. 2 and 18 atomic % for the amino- and methyl-modified surfaces, respectively]. Although peptide binding is generally moderated by the physicochemical characteristics of the adsorbing peptide, the introduction of such a small degree of functionality onto silica particles was sufficient to produce drastic changes in adsorption at the silica/aqueous interface. In addition, an increase in peptide adsorption with an increasing particle size, independent of the nature and properties of the peptide, was observed. This particle size effect is attributed to a shift of the dominant binding mechanism toward electrostatic interactions on larger SiNPs. The data presented demonstrate that particle size and surface functionality are both parameters that can substantially influence (bio)molecule uptake via modulation or selection of specific binding modes at the silica/peptide interface. These results are applicable to the design and development of interfaces with specific adsorption/affinity response for biomedical applications, where uptake is important, such as drug delivery. Further, they provide important insights on how peptide affinity and selection during biopanning can be determined by small changes in surface chemistry of the surface of a target that can, in some instances, be associated with the presence of impurities.