Microchimica Acta

, Volume 184, Issue 2, pp 621–626 | Cite as

In-line monitoring of pH and oxygen during enzymatic reactions in off-the-shelf all-glass microreactors using integrated luminescent microsensors

  • Simon A. Pfeiffer
  • Sergey M. Borisov
  • Stefan Nagl
Short Communication


We describe a maskless photopolymerization technique for integration of luminescent sensors for determination of pH values and dissolved oxygen (DO) into commercially available all-glass microfluidic reactors (in sizes as small as 43 ± 3 μm for both DO and pH sensors). The sensor spots are poly(ethyleneglycol acrylate)-based and obtained by photopolymerization of oligomers in the presence of optical probes for oxygen and pH values, respectively. The resulting devices were applied to in-line monitoring of enzymatic conversions of acetylcholine and glucose (by using acetylcholine esterase and glucose oxidase, respectively) on the microscale. The detection limits are 258 μM and 505 μM for acetylcholine and glucose, respectively. The method has a large potential in terms of monitoring enzymatic and other chemical reactions on the microscale in that it does not require special instrumentation apart from a standard widefield fluorescence microscope.

Graphical abstract

Microstructures down to 43 μm in diameter and capable of luminescent sensing of pH and dissolved oxygen were integrated inside all-glass microreactors using oligo(ethylene glycol diacrylate)-based photopolymers doped with luminescent probes. The sensors were then used for in-line monitoring of enzymatic conversions of acetylcholine and glucose.


Maskless photopolymerization Commercial micro flow reactor Microfluidic chip pH sensor Oxygen sensor Chemical sensor Integrated sensor Glucose oxidase Acetylcholine esterase Fluorescence microscopy 



Financial support of this work by the German Research Foundation (DFG, NA 947/1-2 and 2-1) is gratefully acknowledged.

Compliance with ethical standards

The author(s) declare that they have no competing interests.

Supplementary material

604_2016_2021_MOESM1_ESM.docx (118 kb)
ESM 1 (DOCX 117 kb)


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Copyright information

© Springer-Verlag Wien 2016

Authors and Affiliations

  1. 1.Institut für Analytische ChemieUniversität LeipzigLeipzigGermany
  2. 2.Institut für Analytische Chemie und LebensmittelchemieTechnische Universität GrazGrazAustria
  3. 3.Institut für Angewandte Chemie, Fakultät für NaturwissenschaftenBrandenburgische Technische Universität Cottbus-SenftenbergSenftenbergGermany
  4. 4.The Hong Kong University of Science and TechnologyHong KongPeople’s Republic of China

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