Oxygen sensor nanoparticles for monitoring bacterial growth and characterization of dose–response functions in microfluidic screenings

• Published in: Mikrochimica acta (1966) Vol. 182; no. 1-2; pp. 385 - 394
• Main Authors: Cao, Jialan, Nagl, Stefan, Kothe, Erika, Köhler, J. Michael
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01-01-2015; Springer
• Subjects: Analytical Chemistry; Bacteria; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Cultivation; Detection; Droplets; Microengineering; Microfluidics; Monitoring; Nanochemistry; Nanostructure; Nanotechnology; Original Paper; Screening; Streptomyces acidiscabies; Oxygen sensor; Droplet-based microfluidics; Optical probe-doped micro and nanoparticles; Micro cultivation; Highly-resolved dose/response function
• ISSN: 0026-3672; 1436-5073
• DOI: 10.1007/s00604-014-1341-3

We are presenting a microfluidic droplet-based system for non-invasive, simultaneous optical monitoring of oxygen during bacterial cultivation in nL-sized droplets using ~350 nm nanobeads made from polystyrene and doped with the NIR-emitting oxygen probe platinum (II) 5, 10, 15, 20-
meso
-tetraphenyltetrabenzoporphyrin (PtTPTBP). Data were readout by a two-channel micro flow-through fluorimeter and a two-channel micro flow-through photometer. The time-resolved miniaturized optical multi endpoint detection was applied to simultaneously sense dissolved oxygen, cellular autofluorescence, and cell density in nL-sized segments. Two bacterial strains were studied that are resistant to heavy metal ions, viz.
Streptomyces acidiscabies
E13 and
Psychrobacillus psychrodurans
UrPLO1. The study has two main features in that it demonstrates (a) the possibility to monitor the changes in oxygen partial pressure during metabolic activity of different bacterial cultures inside droplets, and (b) the efficiency of droplet-based microfluidic techniques along with multi-parameter optical sensing for highly resolved microtoxicological screenings in aquatic systems.
Graphical Abstract
Microfluidic droplet-based system with multi-parameter optical sensing for bacterial cultivation and highly resolved microtoxicological screenings in nanoliter droplets.