Surfaces with films of protein are a key component of most biosensor designs. An inherent problem with preparing the sensing element is the self-aggregation of proteins, to form multilayers and aggregates. Our strategy for preparing sensor surfaces uses the selectivity of nanopatterned organosilanes to control the deposition of proteins such as fibronectin and fibrinogen. Nanopatterns of organosilanes can be produced using particle lithography as spatially selective substrates for binding proteins. Two strategies were tested for protein patterning. Monodispersed silica mesospheres were used as a surface mask to accomplish particle lithography. Nanoholes were prepared within a film of octadecyltrichlorosilane (OTS) and filled with (3-trimethoxysilylpropyl)diethylenetriamine (DETA). The methyl headgroups of OTS provide a resist to prevent nonspecific binding of protein. Nanodots of DETA were treated with EDC/NHS to react with carboxylic acids on the fibronectin to form an amide bond with the primary amine of the protein (fibronectin). Fibronectin has numerous functions in processes such as cell adhesion, growth, migration, and differentiation. Fibrinogen is a glycoprotein that helps in forming blood clots. It has a rod-like shape with dimensions of 9 × 48 × 6 nm. A second strategy used nanopatterns of (3-mercaptopropyl)trimethoxysilane (MPTMS) to bind protein with sulfo-SMCC (4-(sulfosuccinimidyl-4-[N-maleimidomethyl]cyclohexane-1-carboxylate), which is a water-soluble heterobifunctional protein crosslinker. The sulfo-SMCC reagent can conjugate glycoproteins, such as fibrinogen. The organosilane and protein nanopatterns were characterized with tapping-mode atomic force microscopy (AFM).

Patterning proteins at the nanoscale using spatially selective surfaces prepared by particle lithography

251st National Meeting (2016)

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