Recent advances toward commercialization of a new generation of
low-cost LED- and OLED-based monitors for
dissolved oxygen (DO), and multiple (bio)analytes such as glucose, lactate, alcohol, and cholesterol are described.
The design of the DO monitors, which contain no optical fibers, filters, mirrors, or lens, is significantly simpler and
consequently lower-cost than that of commercial LED-based DO monitors. The multiple (bio)analyte monitors are
based on a DO monitor and the oxidase enzyme specific to each analyte. The potential advantages and
disadvantages of the OLED- vs LED-based monitors is also discussed.
With the goal of developing microfluidic platforms for sensing applications, flash-free micro
patterns were embossed in polypropylene surfaces with ultrasonic heating for a biosensing
lab-on-CD application. The embossed features were designed to act as reservoirs, valves, and reaction
chambers to allow, in combination with a compact sensing platform, the monitoring of analyte levels
using a standard PC-CD player. To generate the compact sensor, as an example, we chose the
photoluminescence (PL)-based detection of lactate and glucose using an OLED-based sensing
platform. Once embossed, the surface energy of the plastic substrate was chemically modified to
make it hydrophilic. Reagents, placed in separate reservoirs, were directed through burst valves
towards a reaction chamber via CD rotation. Lactate or glucose were monitored by measuring the
effect of the related dissolved oxygen level on the PL decay time of an oxygen-sensitive dye,
following analyte oxidation catalyzed by a suitable specific oxidase enzyme. The results demonstrate
the potential of integrating OLEDs as excitation sources in PL-based sensors with microfluidic CD-based
platforms, including for simultaneous multiple analyses.