A printed nanolitre-scale bacterial sensor array

• Published in: Lab on a chip 2011-01, Vol.11 (1), p.139-146
• Main Authors: Melamed, Sahar, Ceriotti, Laura, Weigel, Wilfried, Rossi, François, Colpo, Pascal, Belkin, Shimshon
• Format: Article
• Language: English
• Subjects: Bacteria; Bacterial Adhesion; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Escherichia; Escherichia coli - cytology; Escherichia coli - genetics; Escherichia coli - metabolism; Genetic Engineering; Microbial Viability; Tissue Array Analysis - instrumentation; Tissue Array Analysis - methods
• ISSN: 1473-0197; 1473-0189
• DOI: 10.1039/c0lc00243g

The last decade has witnessed a significant increase in interest in whole-cell biosensors for diverse applications, as well as a rapid and continuous expansion of array technologies. The combination of these two disciplines has yielded the notion of whole-cell array biosensors. We present a potential manifestation of this idea by describing the printing of a whole-cell bacterial bioreporters array. Exploiting natural bacterial tendency to adhere to positively charged abiotic surfaces, we describe immobilization and patterning of bacterial "spots" in the nanolitre volume range by a non-contact robotic printer. We show that the printed Escherichia coli -based sensor bacteria are immobilized on the surface, and retain their viability and biosensing activity for at least 2 months when kept at 4 °C. Immobilization efficiency was improved by manipulating the bacterial genetics (overproducing curli protein), the growth and the printing media (osmotic stress and osmoprotectants) and by a chemical modification of the inanimate surface (self-assembled layers of 3-aminopropyl-triethoxysilane). We suggest that the methodology presented herein may be applicable to the manufacturing of whole-cell sensor arrays for diverse high throughput applications. A nanolitre scale array of genetically engineered sensor bacteria, "tailored" to emit a dose dependent optical signal in the presence of target compounds, has been deposited on a modified glass surface, retaining their biosensing capabilities over prolonged periods.