Christy Haynes

There are a variety of small molecule toxins found in crops that can be extremely carcinogenic to humans, posing dangerous hazards in food production and consumption. Current detection methods for these small molecules are expensive and lack a universal sensing technique to detect a multitude of toxins in complex food matrices. This work exploits commercially available polymers as capture agents for various toxin targets. The capture agents are immobilized on plasmonic substrates known as FONs, or film over nanospheres, based on their end group reactivity while maintaining an affinity for a target. These FONs with short, anchored polymer chains serve as a novel sensing system when paired with surface-enhanced Raman spectroscopy (SERS). SERS is an attractive analytical technique due to its high enhancement factors and its ability to assign specific vibrational modes to certain molecules at very low concentrations. By providing fingerprint spectra for various targets, one can easily detect for these them in relevant complex matrices. While investigating varying polymer chain length, anchoring chemistry, and attachment schemes, this work demonstrates optimization of SERS sensing to achieve limits of detection comparable to current detection methods with a simpler and more flexible signal transduction mechanism. This group plans to use computational studies to model various mycotoxin and monomer vibrational modes to compare to the experimental work. From there, they can make direct molecular hypotheses in regards to hydrogen bonding between polymer and mycotoxin.