Institute of Condensed Matter and Nanosciences , Université catholique de Louvain , Place Louis Pasteur (L4.01.10) , 1348 Louvain-la-Neuve , Belgium.
Jerzy Haber Institute of Catalysis and Surface Chemistry , Polish Academy of Sciences , Niezapominajek 8 , PL30239 Krakow , Poland.
Langmuir. 2018 Mar 6;34(9):3037-3048. doi: 10.1021/acs.langmuir.7b04179. Epub 2018 Feb 19.
Proteins at interfaces are a key for many applications in the biomedical field, in biotechnologies, in biocatalysis, in food industry, etc. The development of surface layers that allow to control and manipulate proteins is thus highly desired. In previous works, we have shown that mixed polymer brushes combining the protein-repellent properties of poly(ethylene oxide) (PEO) and the stimuli-responsive adsorption behavior of poly(acrylic acid) (PAA) could be synthesized and used to achieve switchable protein adsorption. With the present work, we bring more insight into the rational design of such smart thin films by unravelling the role of PEO on the adsorption/desorption of proteins. The PEO content of the mixed PEO/PAA brushes was regulated, on the one hand, by using PEO with different molar masses and, on the other hand, by varying the ratio of PEO and PAA in the solutions used to synthesize the brushes. The influence of ionic strength on the protein adsorption behavior was also further examined. The behavior of three proteins-human serum albumin, lysozyme, and human fibrinogen, which have very different size, shape, and isoelectric point-was investigated. X-ray photoelectron spectroscopy, quartz crystal microbalance, atomic force microscopy, and streaming potential measurements were used to characterize the mixed polymer brushes and, in particular, to estimate the fraction of each polymer within the brushes. Protein adsorption and desorption conditions were selected based on previous studies. While brushes with a lower PEO content allowed the higher protein adsorption to occur, fully reversible adsorption could only be achieved when the PEO surface density was at least 25 PEO units per nm. Taken together, the results increase the ability to finely tune protein adsorption, especially with temporal control. This opens up possibilities of applications in biosensor design, separation technologies, nanotransport, etc.
界面上的蛋白质是生物医学领域、生物技术、生物催化、食品工业等许多应用的关键。因此，人们非常希望开发出能够控制和操纵蛋白质的表面层。在以前的工作中，我们已经表明，可以合成结合了聚环氧乙烷（PEO）的蛋白质排斥特性和聚（丙烯酸）（PAA）的刺激响应吸附行为的混合聚合物刷，并将其用于实现可切换的蛋白质吸附。在本工作中，我们通过揭示 PEO 在蛋白质吸附/解吸中的作用，为这种智能薄膜的合理设计提供了更多的见解。一方面，通过使用不同摩尔质量的 PEO 来调节混合 PEO/PAA 刷中的 PEO 含量，另一方面，通过改变用于合成刷的溶液中 PEO 和 PAA 的比例来调节 PEO 含量。还进一步研究了离子强度对蛋白质吸附行为的影响。研究了三种具有非常不同的大小、形状和等电点的蛋白质（人血清白蛋白、溶菌酶和人纤维蛋白原）的吸附行为。X 射线光电子能谱、石英晶体微天平、原子力显微镜和流动电势测量用于表征混合聚合物刷，特别是用于估计刷中每种聚合物的分数。根据以前的研究选择了蛋白质吸附和解吸条件。虽然 PEO 含量较低的刷允许更高的蛋白质吸附，但只有当 PEO 表面密度至少为 25 个 PEO 单位/纳米时，才能实现完全可逆的吸附。总的来说，这些结果提高了精细调节蛋白质吸附的能力，特别是具有时间控制的能力。这为在生物传感器设计、分离技术、纳米传输等方面的应用开辟了可能性。
