UC Riverside

The detection of biomolecules and volatile organic compounds (VOCs) greatly impacts areas such as biomedicine, biomedical diagnostics, industrial process control, air quality, and breath analysis. Concurrently, whispering gallery mode (WGM) resonators present themselves as highly sensitive and specific sensors pertaining to these applications. Polymer-based WGMs offer additional advantages such as biocompatibility, reduced material costs, and straightforward functionalization methods for tailoring towards distinct analytes. One approach to fabricating polymer WGM sensors in a single step is near-field electrospinning (NFES), a variation of far-field electrospinning (FFES) that enables precise deposition control of micron-sized fibers while maintaining the desired high-volume and rapid production. The filamentous M13 bacteriophage has also drawn attention in the field of biosensing as a promising selective bioreceptor due to the high copy numbers of its lengthwise modifiable protein coat allowing for a dense arrangement of high-affinity peptides available for analyte binding. Additionally, M13 has demonstrated a general affinity for certain charged molecules based on electrostatic interactions with its available protein coat.In this work, a modified streptavidin-binding M13 phage was mixed with poly (vinyl alcohol) and electrospun to fabricate hybrid polymer/phage microscale fibers that support WGMs in their circular cross-sections. The resulting devices were evaluated as both biosensors and VOC sensors through preliminary experiments using streptavidin and methanol as model analytes. The impact of incorporating M13 into the polymer fibers on the sensor quality factor was characterized, and an increased response to streptavidin addition with increasing surface concentration was confirmed. Furthermore, the polymer/phage device exhibited a heightened response to methanol exposure compared to the pure polymer device, indicating promising increased affinity for small polar molecules like VOCs.