Meso-scale fluidic devices with chemical sensors for biological applications

Molecular oxygen and humidity are some of the major environmental quantities being measured for various industrial and commercial applications. This dissertation focuses on the design, fabrication and characterization of optofluidic biosensor systems for oxygen and humidity quantification using color charge-coupled device (CCD) camera as a photodetector and LED panel as an excitation source. Meso-scale fluidic devices with integrated oxygen and humidity sensors for potential applications to hydrotropic and oxytropic studies of small plant roots have been investigated in this study. Meso-scale sensor platform was fabricated using porphyrine complex as the sensitive dye embedded within Ethyl Cellulose (EC) polymer matrix. Green LED light displayed from the light panel helped in exciting the oxygen complex by emitting varied fluorescence emission corresponding to oxygen. This method of optical oxygen imaging helps in wide area distribution over the sensor platform. The root tip response to environmental stimuli by directed growth plays a major role in plant development. With these tropic responses of roots, plants can help themselves during environmental risks such as drought conditions. Different fluidic devices were fabricated with embedded humidity sensors within the device to study the effect of tropic responses. Hydrotropic behavior of corn roots was analyzed along with humidity gradient quantification using color charge-coupled device (CCD) camera for both imaging of the plant root and profiling of humidity distribution. Successfully created and analyzed the humidity gradient which resulted in root orientation because of hydrotropic response indicating the effectiveness of this device for further biological applications --Abstract, page iv