@article{WagnerLazarSchnakenbergetal.2016,
  author    = {Wagner, Tom and Lazar, Jaroslav and Schnakenberg, Uwe and B{\"o}ker, Alexander},
  title     = {In situ Electrothemical Impedance Spectroscopy of Electrostatically Driven Selective Gold Nanoparticle Adsorption on Block Copolymer Lamellae},
  series = {Trials},
  volume    = {8},
  journal   = {Trials},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1944-8244},
  doi       = {10.1021/acsami.6b07708},
  pages     = {27282 -- 27290},
  year      = {2016},
  abstract  = {Electrostatic attraction between charged nano particles and oppositely charged nanopatterned polymeric films enables tailored structuring of functional nanoscopic surfaces. The bottom-up fabrication of organic/inorganic composites for example bears promising potential toward cheap fabrication of catalysts, optical sensors, and the manufacture of miniaturized electric circuitry. However, only little is known about the time-dependent adsorption behavior and the electronic or ionic charge transfer in the film bulk and at interfaces during nanoparticle assembly via electrostatic interactions. In situ electrochemical impedance spectroscopy (EIS) in combination with a microfluidic system for fast and reproducible liquid delivery was thus applied to monitor the selective deposition of negatively charged gold nanoparticles on top of positively charged poly(2-vinylpyridinium) (qP2VP) domains of phase separated lamellar poly(styrene)-block-poly(2-vinylpyridinium) (PS-b-qP2VP) diblock copolymer thin films. The acquired impedance data delivered information with respect to interfacial charge alteration, ionic diffusion, and the charge dependent nanoparticle adsorption kinetics, considering this yet unexplored system. We demonstrate that the selective adsorption of negatively charged gold nanoparticles (AuNPs) on positively charged qP2VP domains of lamellar PS-b-qP2VP thin films can indeed be tracked by EIS. Moreover, we show that the nanoparticle adsorption kinetics and the nanoparticle packing density are functions of the charge density in the qP2VP domains.},
  language  = {en}
}
@article{DaiMateGlebeetal.2018,
  author    = {Dai, Xiaolin and Mate, Diana M. and Glebe, Ulrich and Garakani, Tayebeh Mirzaei and K{\"o}rner, Andrea and Schwaneberg, Ulrich and B{\"o}ker, Alexander},
  title     = {Sortase-mediated ligation of purely artificial building blocks},
  series = {Polymers},
  volume    = {10},
  journal   = {Polymers},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2073-4360},
  doi       = {10.3390/polym10020151},
  pages     = {13},
  year      = {2018},
  abstract  = {Sortase A (SrtA) from Staphylococcus aureus has been often used for ligating a protein with other natural or synthetic compounds in recent years. Here we show that SrtA-mediated ligation (SML) is universally applicable for the linkage of two purely artificial building blocks. Silica nanoparticles (NPs), poly(ethylene glycol) and poly(N-isopropyl acrylamide) are chosen as synthetic building blocks. As a proof of concept, NP-polymer, NP-NP, and polymer-polymer structures are formed by SrtA catalysis. Therefore, the building blocks are equipped with the recognition sequence needed for SrtA reaction-the conserved peptide LPETG-and a pentaglycine motif. The successful formation of the reaction products is shown by means of transmission electron microscopy (TEM), matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-ToF MS), and dynamic light scattering (DLS). The sortase catalyzed linkage of artificial building blocks sets the stage for the development of a new approach to link synthetic structures in cases where their synthesis by established chemical methods is complicated.},
  language  = {en}
}