Negative Surface Charge Effect on Surface-Enhanced Raman Scattering (SERS) Substrates for Cancer Biomarker Detection

Abstract

Record ID: 244

Student Major: Chemistry 

Project Advisor: Pietro Strobbia

Abstract: Cancer detection is currently done in the form of biopsies. This is a technique that is normally for patients that are showing symptoms of cancer. Although this is a reliable way to detect cancer, current biopsies are invasive, and may be completed too late in the progression of the cancer. An alternative is the switch to liquid biopsies (blood or saliva samples), which are less invasive. Also, they could be done more easily and frequently for patients at risk but not showing any symptoms. By screening, we can have early diagnoses and find more effective treatment.Surface-enhanced Raman scattering (SERS) is a potential candidate to detect cancer in liquid biopsies from Raman-active cancer biomarkers. These biomarkers are present at low concentration in liquid biopsies, but they can be detected with sensitive SERS substrates. Therefore, SERS could be a less invasive alternative to tissue biopsies. In our lab, we are testing this hypothesis by developing SERS substrates with gold nanostars coated with silver for plasmonic enhancement.In this work, we are determining what surface charge on the substrate helps our biomarker give the highest intensity. We tested substrates bare (no surface charge), with 6-mercapto-1-hexanol (neutral), and with 4-mercaptobenzoic acid (negative). For testing purposes, liposomes, an extracellular vesicle (EV), will be used in place of cancerous exosomes, a blood EV biomarker, because liposomes’ Raman profile are well-known. Once the best surface charge is determined, substrates will be tested with exosomes, then clinical samples.