title: Directed assembly of living Pseudomonas aeruginosa bacteria on PEI patterns generated by nanoxerography for statistical AFM bioexperiments.
abstract: Immobilization of living micro-organisms on predefined areas of substrates is a prerequisite for their characterizations by atomic force microscopy (AFM) in culture media. It remains challenging since micro-organisms should not be denatured but attached strongly enough to be scanned with an AFM tip, in a liquid phase. In this work, a novel approach is proposed to electrostatically assemble biological objects of interest on 2 nm thick polyethylenimine (PEI) patterns fabricated by nanoxerography. This nanoxerography process involves electrostatic trapping of PEI chains on negatively charged patterns written on electret thin films by AFM or electrical microcontact printing. The capability of this approach is demonstrated using a common biological system, Pseudomonas aeruginosa bacteria. These negatively charged bacteria are selectively assembled on large scale arrays of PEI patterns. In contrast to other PEI continuous films commonly used for cell anchoring, these ultrathin PEI patterns strongly attached on the surface do not cause any denaturation of the assembled Pseudomonas aeruginosa bacteria. AFM characterizations of large populations of individual living bacteria in culture media can thus be easily performed through this approach, providing the opportunity to perform representative statistical data analysis. Interestingly, this process may be extended to any negatively charged micro-organism in solution.
authors.affiliation: Université de Toulouse , LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, F-31400 Toulouse, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Jauvert
authors.forename: Etienne
authors.initials: E
authors.lastname: Palleau
authors.forename: Etienne
authors.initials: E
authors.lastname: Dague
authors.forename: Laurence
authors.initials: L
authors.lastname: Ressier
mesh_terms: D003470:Culture Media / Q000737:chemistry; D018625:Microscopy, Atomic Force; D011094:Polyethyleneimine / Q000737:chemistry; D011550:Pseudomonas aeruginosa / Q000737:chemistry* / Q000648:ultrastructure; D013379:Substrate Specificity; D013499:Surface Properties
chemical_list: D003470:Culture Media; D011094:Polyethyleneimine
keywords: PEI; Pseudomonas aeruginosa bacteria; atomic force microscopy; directed assembly; nanoxerography