EMBEDDING TAPERED FIBER BIOSENSORS WITHIN MICROFLUIDIC CHANNELS FOR BACTERIAL SENSING
Authors:Adrian Ortiz, Martin Sanchez
Mentor:Ertan Salik, Associate Professor, Physics and Astronomy, California Polytechnic State University - Cal Poly
There is an urgent need for portable, simple, cost-effective, biosensor systems with sufficient sensitivity, specificity, and speed for rapid and timely detection and quantitation of pathogens of economic and public health significance. Current methods employed using polymerase chain reaction take as much as 8 hours to days or weeks, from sampling to result. Recent Shiga toxin producing E. coli (STEC) O157:H7, Salmonella and Listeria outbreaks resulted in thousands of illnesses and several deaths, in addition to costing millions of dollars in associated expenses. We are developing fiber optic biosensors to address this important need.Specifically we fabricateoptical fiber tapers by heating and pulling standard glass optical fibers, and then immobilize antibodies on their surfaces. For bacterial sensing, the sensor can be immersed in a solution where bacteria are present. However, when there are very few (<1000 cells/mL) bacterial cells in a solution, the likelihood of capturing them on the biosensor surface is preventively small. To increase sensitivity, we aim to perform bacterial detection when the sensor is placed within microfluidic channels. Here, we present our preliminary experiments for tapered fiber biosensors embedded in various types of microchannels. We demonstrated that the sensor can endure fast liquid flow, and sensor transmission spectrum can be reliably monitored. We also show results of our tests with salt solutions with varying concentrations for sensors within a microfluidic channel.