Many experiments and applications require the chemical coupling of target molecules to surfaces, during which the elimination of nonspecific interactions presents a difficult challenge. We report on a technologically accessible surface passivation and chemical conjugation method based on an NHS end-labeled F127 Pluronic block copolymer (F127-NHS). To quantify interactions between the F127-NHS surface and magnetic microspheres, we developed a simple assay: the microsphere adhesion by gravity, inversion, then counting, or “MAGIC” assay. To improve blocking of microspheres while maintaining the ability to chemically couple additional molecules, we implemented a pH-dependent two-step chemical modification process for amine microspheres. This process achieves an extremely high level of blocking nonspecific interactions (less than 2% nonspecific adhesion) for a variety of microsphere surface charges and chemical functionalities. We also demonstrate the ability to specifically tether magnetic microspheres to an F127-NHS surface, using single DNA molecules. Using the DNA microspheres, we establish the applicability of the surface for force spectroscopy (stable with an applied load >30 pN) via the massively parallel technique of centrifuge force microscopy. Finally, we demonstrate that the surface can be used in fluorescence studies with a fluorogenic peptide cleavage assay, with high levels of blocking achieved for both the fluorogenic peptide and trypsin. These results suggest applications including, but not limited to, single-molecule force spectroscopy and fluorescence, biosensors, medical implants, and anti-biofouling, which could make use of the F127-NHS surface.

中文翻译：

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修饰的Pluronic F127表面用于生物缀合和阻止微球和生物大分子的非特异性吸附

许多实验和应用都需要将目标分子化学偶联到表面上，在此过程中消除非特异性相互作用是一项艰巨的挑战。我们报告了一种基于NHS末端标记的F127 Pluronic嵌段共聚物（F127-NHS）的技术可及的表面钝化和化学共轭方法。为了量化F127-NHS表面与磁性微球之间的相互作用，我们开发了一种简单的测定法：通过重力，倒置，然后计数或“ MAGIC”测定法测定微球的粘附性。为了改善微球的封闭性，同时保持化学偶联其他分子的能力，我们对胺微球实施了pH依赖性的两步化学修饰工艺。对于各种微球表面电荷和化学官能团，该过程实现了极高的阻断非特异性相互作用的水平（小于2％的非特异性粘附力）。我们还展示了使用单个DNA分子将磁性微球特异性束缚到F127-NHS表面的能力。我们使用DNA微球，通过大规模平行的离心力显微镜技术，建立了表面力谱的适用性（施加的载荷> 30 pN稳定）。最后，我们证明了该表面可用于荧光肽裂解试验的荧光研究中，并且对荧光肽和胰蛋白酶均具有高水平的阻断作用。这些结果表明应用包括但不限于单分子力光谱学和荧光，