Water-swollen microgels (MGs) with complex architectures, being soft, deformable and with smooth interfaces are emerging polymer colloids for advanced materials. In order to characterize the structure and dynamics of individual MG structures, there directed immobilization is necessary. We report the synthesis of DNA functionalized poly(N-vinylcaprolactam-co-N-(methacryloxy)succinimide) MGs. The MGs were synthesized by a precipitation polymerization process and single stranded, amine-terminated DNA (ssDNA) was coupled to succinimide groups of the MGs. Thereby the thermal-responsiveness of the DNA-MGs is retained.<br/>To achieve the directed immobilization of individual MGs onto a solid support, gold nanoparticles (AuNPs) were deposited with well-defined inter-particle distances. Prior to functionalizing the AuNPs with ssDNA having a base sequence complementary to the DNA-MGs, a highly fluorinated backfill covering the inter-particulate surface of the wafer was introduced. This backfill reduces unspecific binding of the hydrophilic MGs and minimizes the interaction of immobilized MGs with the substrate. The immobilization of the MGs onto the substrates was realized by sequence specific DNA hybridization. Thus, immobilization is highly controllable and reversible. We characterized the immobilized MGs by scanning electron microscopy (SEM) as well as atomic force microscopy (AFM) and revealed that the immobilized MGs retain in their spherical shape.<br/>In an analogous procedure the DNA-MG were immobilized on glass substrates and functionalized with fluorescently labeled DNA. This allows imaging individual MGs by means of superresolution fluorescence microscopy, whereby the MG remain in the close-to-solution state.

Directed immobilization of thermo-responsive functionalized microgels via DNA

255th National Meeting (2018)

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