Stefano Tugulu

Polymer Brushes via Surface-Initiated Controlled Radical Polymerization: Synthesis, Characterization, Properties, and Applications

Keywords: Fragmentation Chain-Transfer ; Self-Assembled Monolayers ; Walled Carbon Nanotubes ; Well-Defined Polymer ; Nitroxide-Mediated Polymerization ; Block-Copolymer Brushes ; Poly(Methyl Methacrylate) Brushes ; Transfer Raft Polymerization ; Quartz-Crystal Microbalance ; Poly(Acrylic Acid) Brushes Reference EPFL-REVIEW-148464doi:10.1021/cr900045aView record in Web of Science Record created on 2010-04-23, modified on 2017-05-10

Stability and Nonfouling Properties of Poly(poly(ethylene glycol) methacrylate) Brushes under Cell Culture Conditions

This paper investigates the stability and nonfouling properties of poly(poly(ethylene glycol) methacrylate) (PPEGMA) brushes prepared by surface-initiated atom transfer radical polymerization from SiO(x) substrates modified with a trimethoxysilane-based ATRP initiator. At high chain densities, PPEGMA brushes were found to detach rapidly from glass or silicon substrates. Detachment of the PPEGMA brushes could be monitored with contact angle measurements, which indicated a decrease in the receding water contact angle upon detachment. Detachment of the PPEGMA brushes also resulted in an increase in nonspecific protein adsorption. The stability, and as a consequence the long-term nonfouling properties, of the PPEGMA brushes could be improved by tailoring the brush density and, to a lesser extent, the molecular weight of the polymer chains. By appropriate decrease of the grafting density, the stability of the brushes in cell culture medium could be improved from less than 1 to more than 7 days, without compromising the nonfouling properties.

Protein Function Microarrays Based on Self‐Immobilizing and Self‐Labeling Fusion Proteins

Protein microarrays are an attractive approach for the high‐throughput analysis of protein function, but their impact on proteomics has been limited by the technical difficulties associated with their generation. Here we demonstrate that fusion proteins of O6‐alkylguanine‐DNA alkyltransferase (AGT) can be used for the simple and reliable generation of protein microarrays for the analysis of protein function. Important features of the approach are the selectivity of the covalent immobilization; this allows for direct immobilization of proteins out of cell extracts, and the option both to label and to immobilize AGT fusion proteins, which allows for direct screening for protein–protein interactions between different AGT fusion proteins. In addition to the identification of protein–protein interactions, AGT‐based protein microarrays can be used for the characterization of small molecule–protein interactions or post‐translational modifications. The potential of the approach was demonstrated by investigating the post‐translational modification of acyl carrier protein (ACP) from E. coli by different phosphopantetheine transferases (PPTases), yielding insights into the role of selected ACP amino acids in the ACP–PPTase interaction.