This paper reports a robust polymer based centrifugal microfluidic analysis system that can provide parallel
detection of multiple allergens in vitro. Many commercial food products (milk, bean, pollen, etc.) may introduce allergy
to people. A low-cost device for rapid detection of allergens is highly desirable. With this as the objective, we have
studied the feasibility of using a rotating disk device incorporating centrifugal microfluidics for performing actuationfree
and multi-analyte detection of different allergen species with minimum sample usage and fast response time.
Degranulation in basophils or mast cells is an indicator to demonstrate allergic reaction. In this connection, we used
acridine orange (AO) to demonstrate degranulation in KU812 human basophils. It was found that the AO was released
from granules when cells were stimulated by ionomycin, thus signifying the release of histamine which accounts for
allergy symptoms <sup>[1-2]</sup>. Within this rotating optical platform, major microfluidic components including sample reservoirs,
reaction chambers, microchannel and flow-control compartments are integrated into a single bio-compatible
polydimethylsiloxane (PDMS) substrate. The flow sequence and reaction time can be controlled precisely. Sequentially
through varying the spinning speed, the disk may perform a variety of steps on sample loading, reaction and detection.
Our work demonstrates the feasibility of using centrifugation as a possible immunoassay system in the future.
This work primarily aims to integrate dissolved oxygen sensing capability with a microfluidic platform containing
arrays of micro bio-reactors or bio-activity indicators. The measurement of oxygen concentration is of significance for a
variety of bio-related applications such as cell culture and gene expression. Optical oxygen sensors based on
luminescence quenching are gaining much interest in light of their low power consumption, quick response and high
analyte sensitivity in comparison to similar oxygen sensing devices. In our microfluidic oxygen sensor device, a thin
layer of oxygen-sensitive luminescent organometallic dye is covalently bonded to a glass slide. Micro flow channels are
formed on the glass slide using patterned PDMS (Polydimethylsiloxane). Dissolved oxygen sensing is then performed by
directing an optical excitation probe beam to the area of interest within the microfluidic channel. The covalent bonding
approach for sensor layer formation offers many distinct advantages over the physical entrapment method including
minimizing dye leaching, ensuring good stability and fabrication simplicity. Experimental results confirm the feasibility
of the device.