Discipline: Technology and Engineering
Subcategory: Biomedical Engineering
Chelsie Boodoo - Florida International University
Co-Author(s): Yil-Hwan You and Michael J. McShane
Detecting biomarkers in the body through noninvasive techniques is crucial for monitoring progression of chronic conditions. Prior studies have shown that certain analytes such as glucose may be detected by using planar Surface-Enhanced Raman Scattering (SERS) substrates; however, these materials are rigid and usually cause discomfort when implanted. Soft hydrogel materials containing encapsulated SERS sensors offer an alternative which may circumvent problems such as being rejected by the body. In this project, we studied gold and silver nanoparticles that were coated with mixed thiols due to the possibility that their SERS peaks could provide a way to sense analytes. Gold and silver nanoparticles that are coated with 1-decanethiol (DT) and 6-mercapto-1-hexanol (MH) are expected to selectively partition glucose and other small molecules to the surface of the sensor. This coating can be used to sense analytes with SERS. The concentrations of the thiols and the analytes were changed to make the optimal sensor. The size, absorbance and the Raman scattering were also measured to show the properties of the sensors. The nanosensors were encapsulating in microporous alginate hydrogels and the SERS peaks were compared to the peaks of the freely suspended nanosensors. DT/MH was successfully coated on the silver and gold nanoparticles. The sizes of the nanosensors increased as the concentrations of the thiols increased. The absorbance spectra revealed that the nanoparticles did not aggregate. The SERS peaks in regards to glucose shifted relative to the peaks of DT/MH; however, they were not conclusively concentration dependent. Other analytes such as urea and lactate did not show any spectral changes. Gold and silver nanoparticles were successfully coated with mixed thiols and they were characterized as potential SERS sensors. If the nanosensors are successfully embedded in a hydrogel it can be potentially used as an implantable sensor. The ability to continuously sense physiologically relevant biomarkers in the human body can save numerous lives and promote healthier lifestyles.
Funder Acknowledgement(s): NSF REU supplement (Grant 1403002).
Faculty Advisor: Michael J. McShane, firstname.lastname@example.org
Role: I did everything that was required in this project. I synthesized the gold and silver nanoparticles and I coated them with 1-decanethiol and 6-mercapto-1-hexanol. I experimented with the different concentrations of the thiols and the analytes. I observed how the different analytes (glucose, lactate and urea) interacted with the mixed thiols. To see if these analytes could be detect, Raman spectroscopy was used. UV vis and DLS were used to characterize the nanoparticles. I also did data analysis with OriginPro, Excel, MATLAB, Igor, and Crystal Sleuth. I finally tried to encapsulate these nanoparticles within hydrogels.