This work presents a novel simple and inexpensive technique
for integration of optical oxygen sensors into microfluidic chips made of
glass. The channels of chips are coated with conjugated polymeric nanoparticles
containing a covalently grafted oxygen indicator. The resulting layer of
physically adsorbed nanoparticles shows excellent stability in buffers of
various pH and in presence of a surfactant without noticeable leaching.
The integrated sensors feature ultrafast response (less than
0.2 seconds) and repeatable quenching behavior when exposed to different
concentrations of oxygen present in air or aqueous solutions. They can be
read-out either in lifetime or in ratiometric intensity modalities using
unsophisticated, compact and low-cost fluorescence detection systems such as a
dual RGB/NIR camera or a phase fluorometer.
We also present a new technique for modification of smooth
glass surfaces based on in situ
generation and deposition of dense silica microparticles, which act as an
adsorbent for the oxygen-sensitive nanoparticles. This modification
dramatically improves the loading with the nanoparticles due to increased
surface roughness and maximized contact surface area.
Finally, packed-bed micro reactors with integrated
oxygen-sensing layers and filled with silica beads containing the enzyme
immobilized on its surface are demonstrated to have high potential for
investigation of enzymatic activity.
沒有留言:
張貼留言