Patterning of individual Staphylococcus aureus bacteria onto photogenerated polymeric surface structures

This manuscript describes the fabrication of bacterial surface arrays by using photolithographic techniques having in addition some particularly interesting features. The methodology employed is based on the crosslinking and degradation processes occurring in polystyrene upon exposure to UV light. As a result of both processes, this approach produced different patterns depending not only on the mask but also on the experimental conditions employed. Patterns with nanoscale resolution were formed without the requirement of expensive fine focalization settings. More interestingly, the feasibility of this strategy to incorporate functional groups to modulate the affinity between the bacteria and the surface is demonstrated. In particular, hydrophilic segments, i.e. poly(acrylic acid) that favor bacterial immobilization were introduced. The strategy employed allows not only the incorporation of functional groups but also permits us to fine tune the amount of hydrophilic functional groups. This unique feature has been used to determine the role of surface hydrophilicity on the adhesion of Staphylococcus aureus (S. aureus) onto the different surface patterns. Finally, those surfaces on which both photodegradation and photocrosslinking occurred produced thin patterns largely below the micrometer that have been employed to prepare arrays of isolated S. aureus bacteria. The formation of bacterial arrays of S. aureus on the single-cell level has been a challenge since they exhibit a large tendency to grow in clusters. This technology has great potential for the isolation of single bacteria for diagnosis, and the study of bacterial populations at the single cell level.